Semiconductor stack and process thereof

Abstract

The present disclosure relates to vertical stacks including heterogeneous layers and processes and methods of making the same. The present disclosure also describes devices and systems for making and forming such stacks.

Description

Incorporation by reference The PCT application form is filed simultaneously with this specification as part of this application. Each application identified in the PCT application form filed simultaneously for which this application claims the benefit or priority thereof is incorporated herein by reference in its entirety. Technical Field

[0001] The present disclosure relates to vertical stacks including heterolayers and processes and methods for their manufacture. Background Art

[0002] Controlled deposition of heterolayers remains a challenge. In particular, if high temperature processes are employed, interdiffusion of atoms between these layers may result.

[0003] The background description provided here is for the purpose of generally presenting the background of the technology. The work of the currently named inventors within the scope described in this background art section and aspects of the specification that were not determined to be prior art at the time of filing the application are neither expressly nor impliedly admitted to be prior art to the present technology. Summary of the Invention

[0004] The present disclosure relates to vertical stacks comprising heterolayers. In some instances, the stack includes heteroepitaxial layers. In some instances, such heterolayers or heteroepitaxial layers may include alternating first and second layers; alternating first and second semiconductor layers; alternating semiconductor and sacrificial layers; alternating silicon-containing layers (Si layers) and silicon-germanium-containing layers (SiGe layers); or the like.

[0005] Currently, industry standards rely on thermal chemical vapor deposition (CVD) to obtain epitaxial layers. For vertical stacks comprising many heteroepitaxial layers, using high temperatures (e.g., greater than about 600 °C, 650 °C, 700 °C, 800 °C, 900 °C or higher) can increase the deposition rate, but there is a risk of interdiffusion of atoms between the heterolayers. Additionally, using such high temperatures may reduce the height of the stack that can be grown due to an increase in lattice defect formation under such conditions. While using lower temperatures can reduce interdiffusion and reduce lattice defect formation, the growth rate of the epitaxial layers may be too low for the process to be economically viable. Thus, in one instance, the plasma-based epitaxy methods herein can provide sufficient growth rates for the deposited heterolayers while reducing interdiffusion. Additionally, if low temperature, plasma-based epitaxy is employed, a higher limit of the critical thickness (h c ) can allow for thicker stacks and thicker epitaxial layers, as described more fully herein.

[0006] In a first aspect, the present disclosure encompasses a method of forming a heterolayer on a substrate. In certain embodiments, the method includes: (a) forming a first layer (e.g., a first semiconductor layer) by flowing a first precursor into a reaction chamber and toward the substrate in the presence of a high-energy species; and (b) forming a second layer (e.g., a second semiconductor layer) by flowing a second precursor and an optional third precursor into the reaction chamber and toward the substrate in the presence of a high-energy species.

[0007] In some embodiments, the method further includes: (c) repeating operations (a) and (b) until a predetermined number of layers have been deposited on the substrate. In certain embodiments, the predetermined number of layers is deposited at a temperature of less than about 650 °C or less than about 600 °C.

[0008] In some embodiments, the method further includes (e.g., before operation (a)): providing a substrate in a reaction chamber (e.g., an epitaxial chamber), wherein the substrate is optionally pre-cleaned or optionally pre-treated or at least one of them.

[0009] In some embodiments, the substrate is pre-cleaned, thereby providing a pre-cleaned surface. In other embodiments, the substrate is pre-treated, thereby providing a pre-treated surface. In still other embodiments, the substrate is pre-cleaned and pre-treated, thereby providing a pre-cleaned and pre-treated surface.

[0010] In some embodiments, the high-energy species includes at least one of radicals, metastable species, ions, neutral species, plasmas, photons, radiation, excited molecules, excited atoms, or others described herein, and radicals, metastable species, ions, neutral species, excited molecules, or excited atoms in a plasma-generating form.

[0011] In some embodiments, the high-energy species (e.g., at least one of radicals, metastable species, or other high-energy species described herein) reacts with the first precursor to deposit the first layer on the substrate. In other embodiments, the high-energy species (e.g., at least one of radicals, metastable species, or other high-energy species described herein) reacts with the second precursor to deposit the second layer on the substrate. In still other embodiments, the high-energy species reacts with the second precursor and with the third precursor to deposit the second layer on the substrate. A particular type of high-energy species can be used alone, or two (or more) different types can be used together. For example but not limited to, radicals can be used alone, metastable species can be used alone, or both radicals and metastable species can be used together.

[0012] In some embodiments, the second layer includes a sacrificial layer.

[0013] In other embodiments, the method further includes (e.g., before operation (a) or (b)): (a″′) depositing a buffer layer between the substrate and the first layer or between the substrate and the second layer.

[0014] In some embodiments, operations (a) and (b) occur after an initial layer (e.g., an initial semiconductor layer) is deposited on the substrate. The initial layer can include a layer composed of any semiconductor material described herein (e.g., an epitaxial layer). In other embodiments, operations (a) and (b) occur after a buffer layer is deposited on the substrate.

[0015] In some embodiments, the first precursor is different from the second precursor. In further embodiments, operation (b) includes a third precursor, where the first precursor is the same as the third precursor. Alternatively, the first precursor and the third precursor can be different.

[0016] In some embodiments, operation (a) is performed before operation (b). In other embodiments, operation (b) is performed before operation (a).

[0017] In some embodiments, the method further includes (e.g., before or during operation (a) or operation (b)): filtering high-energy species (e.g., at least one of radicals or metastable species) before the high-energy species (e.g., radicals or metastable species) flow from a remote plasma source to the reaction chamber.

[0018] In some embodiments, high-energy species (e.g., at least one of radicals or metastable species) are generated in a remote plasma source disposed upstream of the reaction chamber. In other embodiments, operation (a) includes: generating high-energy species (e.g., at least one of radicals or metastable species) in the remote plasma source and the flow in operation (a) includes introducing the first precursor downstream of the remote plasma source. In still other embodiments, operation (b) includes: generating high-energy species (e.g., at least one of radicals or metastable species) in the remote plasma source, and the flow in operation (b) includes introducing at least one of the second precursor or the optional third precursor downstream of the remote plasma source.

[0019] In some embodiments, high-energy species (e.g., at least one of radicals or metastable species) are generated in-situ in a portion of the reaction chamber.

[0020] In some embodiments, the energetic species (e.g., at least one of a radical or a metastable species) is generated by a plasma. Non-limiting examples of the plasma include capacitively coupled plasma (CCP), inductively coupled plasma (ICP), transformer coupled plasma (TCP), electron cyclotron resonance (ECR) plasma, surface wave plasma (SWP, e.g., plasma generated using a radial line slot antenna (RLSA)), microwave plasma (MWP), plasma generated using ultraviolet (UV) radiation, low energy plasma (LEP), low temperature plasma (LTP) source, and the like.

[0021] In some embodiments, the energetic species (e.g., at least one of a radical or a metastable species) is generated using a source gas that includes a hydrogen-containing gas or a deuterium-containing gas. In certain embodiments, the hydrogen-containing gas or the deuterium-containing gas is mixed with a carrier gas that includes an inert gas (e.g., at least one of argon, helium, or the like, and combinations thereof).

[0022] In some embodiments, the method further includes (e.g., before or during operation (a), and before or during operation (b)): heating the substrate using a radiant heat source. In some embodiments, the substrate is heated from the front side of the substrate. In other embodiments, the substrate is heated using a pedestal on which the substrate is located (e.g., on the front side). In still other embodiments, the substrate is heated from the back side of the substrate.

[0023] In some embodiments, the first layer includes a silicon-containing layer (Si-containing layer), and the second layer includes a silicon and germanium-containing layer (SiGe-containing layer). In other embodiments, the first layer includes a silicon and germanium-containing layer (SiGe-containing layer), and the second layer includes a silicon-containing layer (Si-containing layer). In certain embodiments, the germanium (Ge) concentration within the layer is in the range of about 10 atomic percent (at.%) to 50 at.%. In still other embodiments, the Ge concentration within the layer forms a concentration gradient (e.g., having a concentration gradient extending within the layer, where the gradient has a concentration change in the range of about 10 atomic percent to 50 atomic percent, 15 atomic percent to 50 atomic percent, 20 atomic percent to 50 atomic percent, 10 atomic percent to 20 atomic percent, 10 atomic percent to 30 atomic percent, and 10 atomic percent to 40 atomic percent, and ranges therebetween).

[0024] In some embodiments, the method further comprises: providing an interface layer between the first layer and the second layer. Such an operation may be provided after operation (a), between operation (a) and operation (b), or after operation (b). In some embodiments, the interface layer is an epitaxial layer. One or more interface layers may be present between the first and second layers. The concentration of one or more atoms (e.g., Si, Ge, Group IV atoms, or other atoms described herein) within each interface layer may be the same or different. The concentration of the atoms may be within any useful range, such as from about 10 atomic % to 50 atomic %. In one example, the concentration of a particular atom is different within two or more different interface layers. In another example, the concentration of a first atom in a first interface layer is the same as the concentration of a second atom in a second interface layer, where the first and second atoms are different. In yet another example, the concentration of a first atom in a first interface layer is different from the concentration of a second atom in a second interface layer, where the first and second atoms are different. In still other embodiments, the concentration of the first atom or the second atom within the layer forms a concentration gradient (e.g., having a concentration gradient extending from about 10 atomic % to 50 atomic %, 15 atomic % to 50 atomic %, 20 atomic % to 50 atomic %, 10 atomic % to 20 atomic %, 10 atomic % to 30 atomic %, and 10 atomic % to 40 atomic %, and ranges therebetween).

[0025] In some embodiments, the method further comprises: exposing the substrate to a plasma between operations (a) and (b). Without wishing to be bound by mechanism, such an exposure operation may be performed on the surface of the first layer or on the surface of the second layer to provide a preparatory surface. In some implementations, this may provide a smoothed surface for depositing the next layer.

[0026] In some embodiments, the method further comprises at least one of the following (e.g., before operation (a)): (a′) pre-cleaning the substrate to provide a pre-cleaned surface of the substrate; or (a") performing a surface pretreatment on the substrate to provide a pre-treated surface of the substrate. In some embodiments, the method comprises performing only operation (a′), only operation (a"), or both operations (a′) and (a"). In some embodiments, the pre-cleaned surface comprises an oxide-free surface. In other embodiments, the pre-treated surface comprises a hydrophobic surface or a passivated surface. Further details regarding the pre-cleaning operation and the pretreatment operation are described herein (e.g., as described in paragraphs

[0277] to

[0404] or elsewhere herein).

[0027] In some embodiments, operation (a′) includes delivering a halogen-containing reagent (e.g., any reagent described herein, including a halogen-containing compound, liquid, solution, or gas), a halogen-containing vapor (e.g., a fluorine-containing vapor), or a halogen-containing plasma (e.g., a fluorine-containing plasma). In other embodiments, operation (a′) includes removing an oxide from the surface of the substrate.

[0028] In some embodiments, operation (a″) includes delivering a hydrogen-containing reagent (e.g., any reagent described herein, including a hydrogen-containing compound, liquid, solution, or gas), a deuterium-containing reagent (e.g., any reagent described herein, including a deuterium-containing compound, liquid, solution, or gas), a hydrogen-containing plasma, or a deuterium-containing plasma. In other embodiments, operation (a″) includes forming a hydrogenated surface or a deuterated surface on the substrate. In still other embodiments, operation (a″) is performed in a reaction chamber.

[0029] In some embodiments, the method further includes (e.g., before operation (a) or after operation (c)) at least one of the following: (c′) performing reactor cleaning of the reaction chamber by removing contaminants from the environment or surface within the reaction chamber after removing the substrate from the reaction chamber or before providing the substrate to the reaction chamber; or (c″) performing reactor treatment of the reaction chamber by passivating the environment or surface within the reaction chamber.

[0030] In some embodiments, the method further includes (e.g., before operation (a)) cleaning or treating the reaction chamber. Further details regarding reactor cleaning operations and reactor treatment operations are described herein (e.g., as described in paragraphs

[0477] to

[0491] or elsewhere herein).

[0031] In some embodiments, at least one of operation (a) or operation (b) includes generating a plasma comprising at least one of a radical or a metastable species. In other embodiments, the generating and the flowing in at least one of operation (a) or operation (b) occur in any order or simultaneously. In still other embodiments, the plasma is generated in a remote plasma source disposed upstream of the reaction chamber. Further details regarding plasma-based deposition operations are described herein (e.g., as described in paragraphs

[0405] to

[0436] or elsewhere herein).

[0032] In some embodiments, a plasma is generated using a source gas comprising a hydrogen-containing gas or a deuterium-containing gas. In some embodiments, the hydrogen-containing gas or the deuterium-containing gas is mixed with a carrier gas comprising an inert gas (e.g., any of those described herein).

[0033] In some embodiments, the first layer has a thickness of from about 5 nanometers (nm) to 60 nm. In other embodiments, the second layer has a thickness of from about 5 nm to 25 nm. In still other embodiments, at least one of the first layer or the second layer each independently has a thickness in the range of from about 3 nm to 60 nm and ranges therebetween (e.g., from about 3 nm to 50 nm, 3 nm to 40 m, 3 nm to 30 nm, 3 nm to 25 nm, 3 nm to 20 nm, 4 nm to 60 nm, 4 nm to 50 nm, 4 nm to 40 nm, 4 nm to 30 nm, 4 nm to 25 nm, 4 nm to 20 nm, 5 nm to 60 nm, 5 nm to 50 nm, 5 nm to 40 nm, 5 nm to 30 nm, 5 nm to 25 nm, 5 nm to 20 nm, 6 nm to 60 nm, 6 nm to 50 nm, 6 nm to 40 nm, 6 nm to 30 nm, 6 nm to 25 nm, 6 nm to 20 nm, 7 nm to 60 nm, 7 nm to 50 nm, 7 nm to 40 nm, 7 nm to 30 nm, 7 nm to 25 nm, 7 nm to 20 nm, 8 nm to 60 nm, 8 nm to 50 nm, 8 nm to 40 nm, 8 nm to 30 nm, 8 nm to 25 nm, 8 nm to 20 nm, 9 nm to 60 nm, 9 nm to 50 nm, 9 nm to 40 nm, 9 nm to 30 nm, 9 nm to 25 nm, 9 nm to 20 nm, 10 nm to 60 nm, 10 nm to 50 nm, 10 nm to 40 nm, 10 nm to 30 nm, 10 nm to 25 nm, or 10 nm to 20 nm).

[0034] In a second aspect, the present disclosure encompasses an apparatus for forming a heterolayer on a substrate. In some embodiments, the apparatus includes: a reaction chamber; a substrate support disposed in the reaction chamber and configured to support the substrate; a plasma source; and one or more controllers configured with instructions for performing any of the methods or any of the operations described herein.

[0035] In some embodiments, the one or more controllers are configured with instructions for performing the following operations: (a) forming a first layer (e.g., a first semiconductor layer) by flowing a first precursor into the reaction chamber and toward the substrate in the presence of high-energy species generated by the plasma; (b) forming a second layer (e.g., a second semiconductor layer) by flowing a second precursor and an optional third precursor into the reaction chamber and toward the substrate in the presence of high-energy species generated by the plasma; and (c) repeating (a) and (b) until a predetermined number of layers have been deposited on the substrate. In certain embodiments, the first layer has an etching behavior different from that of the second layer.

[0036] In some embodiments, the high-energy species generated by the plasma include one or more plasma-generated radicals, plasma-generated metastable species, or plasma-generated ions.

[0037] In some embodiments, the operation (a) of forming the first layer includes reacting the high-energy species generated by the plasma with a first precursor to deposit the first layer on the substrate. In other embodiments, the operation (b) of forming the second layer includes reacting the high-energy species generated by the plasma with a second precursor and an optional third precursor to deposit the second layer on the substrate.

[0038] In some embodiments, the one or more controllers are configured with instructions to perform the following operations (e.g., before operation (a)): (a′) providing a substrate in the reaction chamber.

[0039] In some embodiments, the one or more controllers are configured with instructions to perform the following operations: generating a plasma in operation (a) or operation (b) (e.g., optionally in a remote plasma source), wherein the plasma includes at least one of plasma-generated radicals or plasma-generated metastable species. Non-limiting examples of plasma-generated radicals and plasma-generated metastable species include at least one of hydrogen-containing radicals, deuterium-containing radicals, helium-containing metastable species, or argon-containing metastable species, and combinations thereof. In other embodiments, the generating and the flowing in operations (a) and (b) are performed in any order or simultaneously.

[0040] In some embodiments, the plasma source of the apparatus is an in-situ plasma source disposed in the reaction chamber. In other embodiments, the plasma source is a remote plasma source disposed upstream of the reaction chamber. In further embodiments, the remote plasma source is fluidly coupled to the reaction chamber through one or more gas outlets.

[0041] In some embodiments, the one or more controllers are configured with instructions to perform the following operations: generating a plasma in operation (a) or operation (b), wherein the generating includes generating a plasma in a remote plasma source. In further embodiments, the flowing in operation (a) includes introducing a first precursor downstream of the remote plasma source. In other embodiments, the flowing in operation (b) includes introducing at least one of a second precursor or an optional third precursor downstream of the remote plasma source.

[0042] In some embodiments, the apparatus further includes at least one of a water trap or one or more water pumps. In certain embodiments, the water trap or water pump is located in a processing chamber (e.g., a reaction chamber, an epitaxial chamber, or other chambers described herein) or a module (e.g., a transfer module, a processing module, or other modules described herein). In other embodiments, the water trap or water pump is located at a gas outlet of the one or more gas outlets. In any of the embodiments herein, the water trap or water pump is configured to reduce at least one of the water vapor or oxygen content. In some embodiments, the water trap or water pump is configured to maintain the oxygen content in the reaction chamber at less than about 500 ppb. Non-limiting examples of water pumps include cryopumps, turbopumps, drag pumps, getter pumps, roughing pumps, and other pumps described herein.

[0043] In some embodiments, the one or more gas outlets or gas inlets include stainless steel.

[0044] In some embodiments, the apparatus further includes a purifier fluidly coupled to a gas inlet of the processing chamber (e.g., a reaction chamber, an epitaxial chamber, or other chambers described herein) or a module (e.g., a transfer module, a processing module, or other modules described herein). In certain embodiments, the purifier is configured to reduce at least one of the water vapor or oxygen content.

[0045] In some embodiments, the apparatus further includes a gas line that also includes one or more heaters for baking. In certain embodiments, the one or more heaters (e.g., heating elements) are associated with one or more valves upstream of the reaction chamber.

[0046] In some embodiments, the apparatus further includes one or more heaters (e.g., heating elements) for heating a processing chamber (e.g., a reaction chamber, an epitaxial chamber, or other chambers described herein), a module (e.g., a transfer module, a processing module, or other modules described herein), or a component within the processing chamber or module (e.g., the component can be any of those described herein, such as a showerhead). In certain embodiments, the one or more heaters are configured to reduce at least one of the water vapor or oxygen content.

[0047] In some embodiments, the apparatus further includes one or more coolers (e.g., cooling elements) for cooling a processing chamber (e.g., a reaction chamber, an epitaxial chamber, or other chambers described herein), a module (e.g., a transfer module, a processing module, or other modules described herein), or a component within the processing chamber or module (e.g., the component can be any of those described herein, such as a showerhead).

[0048] In some embodiments, the apparatus further includes an ion filter disposed between a plasma source (e.g., a remote plasma source) and the reaction chamber. In other embodiments, the ion filter is integrated into a showerhead disposed in the reaction chamber. In still other embodiments, the ion filter is located downstream of the plasma source.

[0049] In some embodiments, the plasma source of the apparatus includes a capacitively coupled plasma (CCP) source, an inductively coupled plasma (ICP) source, a transformer coupled plasma (TCP) source, an electron cyclotron resonance (ECR) plasma source, a surface wave plasma (SWP) source, a microwave plasma (MWP) source, a radial line slot antenna (RLSA), a low energy plasma (LEP) source, or a low temperature plasma (LTP) source.

[0050] In some embodiments, the CCP source includes a first power source operatively coupled to a first plate of the CCP source and further includes a second power source operatively coupled to a second plate of the CCP source. In certain embodiments, the plasma frequency is in the range of about 400 kHz to 1000 kHz or about 700 MHz to 2.5 GHz.

[0051] In some embodiments, the SWP source (e.g., RLSA) includes a microwave generator. In certain embodiments, the microwave generator is configured to generate a signal in the frequency range of about 700 MHz to 1 GHz. In other embodiments, the microwave generator provides microwaves having a frequency of about 1 GHz to 100 GHz, such as about 2.45 GHz, 8.35 GHz, 5.8 GHz, 1.98 GHz, or the like. In still other embodiments, the SWP source (e.g., RLSA) includes a plurality of sources arranged in an array, wherein the plurality of sources are configured to diffuse the plasma in a uniform manner.

[0052] In some embodiments, the apparatus further includes a radiant heat source configured to heat the front side of the substrate. In certain embodiments, the radiant heat source is an infrared (IR) lamp. In some embodiments, the radiant heat source is configured to provide radiation having a wavelength in the range of about 400 nm to 1000 nm or 500 nm to 1000 nm. In other embodiments, the apparatus further includes a heating element configured to heat the back side of the substrate. In certain embodiments, the heating element (e.g., a light emitting diode (LED)) is integrated into a substrate support (e.g., a pedestal or a chuck) disposed in the reaction chamber and configured to support the substrate. In any of the embodiments herein, the radiant heat source or the heating element is made of a material that is transparent to the spectrum provided by the source or element and resistant to the reactor cleaning or reactor treatment operations described herein.

[0053] In some embodiments, the reaction chamber includes quartz.

[0054] In some embodiments, the reaction chamber, plasma source, or components disposed within the reaction chamber include a coating (e.g., ceramic, metal, oxide, silicate, and other materials described herein). In other embodiments, the component disposed within the reaction chamber is a showerhead.

[0055] In some embodiments, the reaction chamber is an epitaxial chamber.

[0056] In some embodiments, the apparatus is a multi-station processing chamber.

[0057] In some embodiments, the substrate support includes a heated pedestal. In certain embodiments, the substrate support includes a pedestal at a temperature in the range of about 250 °C to 650 °C. In other embodiments, the substrate support includes a pedestal configured to provide a substrate at a temperature in the range of about 250 °C to 650 °C.

[0058] In some embodiments, the one or more controllers are configured with instructions to perform the following operations: forming a first layer at a first temperature in operation (a) and forming a second layer at a second temperature in operation (b). In certain embodiments, the first temperature is different from the second temperature.

[0059] In some embodiments, the pressure inside the reaction chamber during the formation of the first layer or the second layer is less than about 0.5 Torr. In certain embodiments, the pressure is from about 0.1 Torr to 3 Torr. In still other embodiments, the pressure during formation is from about 0.001 Torr to 1000 Torr (e.g., about 0.001 Torr to 700 Torr, 0.001 Torr to 200 Torr, 0.001 Torr to 100 Torr, 0.001 Torr to 60 Torr, 0.001 Torr to 20 Torr, 0.001 Torr to 10 Torr, 0.001 Torr to 5 Torr, 0.001 Torr to 1 Torr, 0.01 Torr to 1000 Torr, 0.01 Torr to 700 Torr, 0.01 Torr to 200 Torr, 0.01 Torr to 100 Torr, 0.01 Torr to 60 Torr, 0.01 Torr to 20 Torr, 0.01 Torr to 10 Torr, 0.01 Torr to 5 Torr, 0.01 Torr to 1 Torr, 0.1 Torr to 1000 Torr, 0.1 Torr to 700 Torr, 0.1 Torr to 200 Torr, 0.1 Torr to 100 Torr, 0.1 Torr to 60 Torr, 0.1 Torr to 20 Torr, 0.1 Torr to 10 Torr, 0.1 Torr to 5 Torr, 0.1 Torr to 1 Torr, 1 Torr to 1000 Torr, 1 Torr to 700 Torr, 1 Torr to 200 Torr, 1 Torr to 100 Torr, 1 Torr to 60 Torr, 1 Torr to 20 Torr, 1 Torr to 10 Torr, 1 Torr to 5 Torr, and the like).

[0060] In a third aspect, the present disclosure encompasses methods of epitaxially depositing a film. In some embodiments, the method includes: pre-cleaning a surface of a substrate, thereby providing a pre-cleaned surface; pre-treating the surface of the substrate, thereby providing a pre-treated surface; epitaxially depositing a layer (e.g., a semiconductor layer) on the pre-cleaned and pre-treated surface in an epitaxy chamber in the presence of a plasma; removing the substrate from the epitaxy chamber; and performing a reactor clean on the epitaxy chamber.

[0061] In some embodiments, pre-cleaning may include removing oxides. In other embodiments, pre-cleaning includes delivering a halogen-containing reagent (e.g., any of those described herein, including a halogen-containing compound, liquid, solution, or gas), a halogen-containing vapor (e.g., a fluorine-containing vapor), or a halogen-containing plasma (e.g., a fluorine-containing plasma).

[0062] In some embodiments, pre-treatment may include providing a hydrophobic surface or a passivated surface. In other embodiments, pre-treatment includes delivering a hydrogen-containing reagent (e.g., any of those described herein, including a hydrogen-containing compound, liquid, solution, or gas), a deuterium-containing reagent (e.g., any of those described herein, including a deuterium-containing compound, liquid, solution, or gas), a hydrogen-containing plasma, or a deuterium-containing plasma. In certain embodiments, pre-treatment is configured to provide a surface comprising Si-H bonds (e.g., as in a hydrogenated surface) or Si-D bonds (e.g., as in a deuterated surface). In other embodiments, pre-treatment is configured to provide a surface comprising both Si-H bonds and Si-D bonds.

[0063] In some embodiments, epitaxial deposition may include depositing at least one of a first layer or a second layer on the pre-cleaned and pre-treated surface in an epitaxy chamber in the presence of a plasma. In certain embodiments, the pre-treatment operation and the epitaxial deposition operation are performed in the epitaxy chamber. In other embodiments, epitaxial deposition includes a remote plasma. In still other embodiments, epitaxial deposition includes an in-situ plasma.

[0064] In some embodiments, the removal is performed under vacuum.

[0065] In some embodiments, performing the reactor clean is performed before providing the substrate to the epitaxy chamber or after removing the substrate from the epitaxy chamber. In certain embodiments, performing the reactor clean includes delivering a halogen-containing reagent (e.g., any of those described herein, including a halogen-containing compound, liquid, solution, or gas), a halogen-containing vapor (e.g., a fluorine-containing vapor or a chlorine-containing vapor), a halogen-containing plasma (e.g., a fluorine-containing plasma or a chlorine-containing plasma), a hydrogen-containing reagent (e.g., any of those described herein, including a hydrogen-containing compound, liquid, solution, or gas), a deuterium-containing reagent (e.g., any of those described herein, including a deuterium-containing compound, liquid, solution, or gas), a hydrogen-containing plasma, or a deuterium-containing plasma to the epitaxy chamber.

[0066] In some embodiments, the method further comprises (e.g., before epitaxial deposition): depositing a buffer layer between the substrate and the first layer or between the substrate and the second layer.

[0067] In some embodiments, pre-cleaning, pre-treatment, epitaxial deposition, and reactor cleaning are each independently performed at a temperature below about 900 °C, 800 °C, 750 °C, 700 °C, 650 °C, 600 °C, 550 °C, or 500 °C; or at a temperature of about 400 °C to 900 °C or at a temperature of about 400 °C to 700 °C.

[0068] In some embodiments, pre-cleaning, pre-treatment, epitaxial deposition, and reactor cleaning are each independently performed in the presence of a plasma.

[0069] In some embodiments, pre-cleaning is performed in a pre-cleaning chamber, and the epitaxial chamber and the pre-cleaning chamber are disposed in a vacuum platform.

[0070] In some embodiments, the method further comprises (e.g., before epitaxial deposition): transferring the substrate from the pre-cleaning chamber to the epitaxial chamber under vacuum. Such transfer can be performed in any useful manner, e.g., by using a transfer module configured to access both the pre-cleaning chamber and the epitaxial chamber.

[0071] In some embodiments, epitaxial deposition provides a plurality of alternating first and second layers. In some embodiments, the plurality of layers includes more than 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, or more pairs, where each pair includes a single first layer and a single second layer. In other embodiments, the plurality of layers includes more than 1, 2, 3, 4, 5, or more quartets, where each quartet includes two first layers and two second layers.

[0072] In some embodiments, the method further comprises (e.g., after epitaxial deposition): further pre-treating the surface of at least one of the first layer or the second layer, thereby providing a pre-treated surface. In other embodiments, the pre-treated surface includes a passivated surface or a hydrophobic surface, as described herein.

[0073] In some embodiments, the method further comprises (e.g., after or during epitaxial deposition): further preparing the surface of at least one of the first layer or the second layer, thereby providing a prepared surface. In other embodiments, the prepared surface includes a smoothed surface, as described herein.

[0074] In some embodiments, the method further includes (e.g., after performing reactor cleaning): performing reactor treatment by passivating the environment or surface within the epitaxy chamber. In other embodiments, the passivated environment or surface has a reduced halogen content compared to the environment or surface that was present within the epitaxy chamber prior to performing reactor treatment. In some embodiments, passivation includes delivering a hydrogen-containing reagent, a deuterium-containing reagent, a hydrogen-containing plasma, or a deuterium-containing plasma to the epitaxy chamber.

[0075] In a fourth aspect, the present disclosure encompasses a method of forming a stack. In some embodiments, the method includes: pre-cleaning a substrate to provide a pre-cleaned surface; pre-treating the pre-cleaned surface of the substrate to provide a pre-cleaned and pre-treated surface; epitaxially depositing a layer (e.g., a semiconductor layer) on the pre-cleaned and pre-treated surface within an epitaxy chamber in the presence of a plasma; removing the substrate from the epitaxy chamber; and performing reactor cleaning on the epitaxy chamber.

[0076] In some embodiments, the layer includes a plurality of alternating first and second layers (e.g., a plurality of alternating first and second semiconductor layers). In certain embodiments, the plurality of alternating first and second layers includes more than 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, or more pairs, where each pair includes a single first layer and a single second layer.

[0077] In some embodiments, pre-cleaning includes exposing the surface of the substrate to a halogen-containing reagent (e.g., any of those described herein, including a halogen-containing compound, liquid, solution, or gas), a halogen-containing vapor (e.g., a fluorine-containing vapor), or a halogen-containing plasma (e.g., a fluorine-containing plasma).

[0078] In some embodiments, pre-treatment includes exposing the surface of the substrate to a hydrogen-containing reagent (e.g., any of those described herein, including a hydrogen-containing compound, liquid, solution, or gas), a deuterium-containing reagent (e.g., any of those described herein, including a deuterium-containing compound, liquid, solution, or gas), a hydrogen-containing plasma, or a deuterium-containing plasma.

[0079] In some embodiments, epitaxial deposition includes a remote plasma.

[0080] In some embodiments, performing reactor cleaning is performed at least one of before providing the substrate to the epitaxy chamber or after removing the substrate from the epitaxy chamber. In certain embodiments, performing reactor cleaning includes a halogen-containing reagent (e.g., any of those described herein, including a halogen-containing compound, liquid, solution, or gas), a halogen-containing vapor, or a halogen-containing plasma.

[0081] In some embodiments, the method includes (e.g., after epitaxial deposition): depositing a hard mask on the surface of the plurality of alternating first and second layers. In certain embodiments, the hard mask is not an epitaxial layer or deposited epitaxially.

[0082] In some embodiments, the method includes (e.g., before epitaxial deposition): depositing a buffer layer between the substrate and the plurality of alternating first and second layers. In certain embodiments, the buffer layer is an epitaxial layer or deposited epitaxially.

[0083] In some embodiments, pre-cleaning, pre-treatment, epitaxial deposition, and reactor cleaning are each independently performed at a temperature below about 900 °C, 800 °C, 750 °C, 700 °C, 650 °C, 600 °C, 550 °C, or 500 °C.

[0084] In some embodiments, pre-cleaning, pre-treatment, epitaxial deposition, and reactor cleaning are each independently performed in the presence of a plasma.

[0085] In a fifth aspect, the present disclosure encompasses a system or apparatus that includes: at least one pre-cleaning chamber; at least one epitaxial chamber; a plasma source; at least one outlet coupled to a vacuum; one or more process gas inlets coupled to one or more sources; and one or more controllers for controlling the operation, wherein the one or more controllers include machine-readable instructions for performing one or more cycles of operation (e.g., any of those described herein) or for performing one or more methods (e.g., any of those described herein).

[0086] In some embodiments, the pre-cleaning chamber or the epitaxial chamber includes a substrate support configured to support a substrate. In some embodiments, the substrate support is a pedestal or a chuck. In further embodiments, the system or apparatus includes a transfer module configured to transfer the substrate from the pre-cleaning chamber to the epitaxial chamber (e.g., under vacuum).

[0087] In some embodiments, the one or more process gas inlets are coupled to one or more fluorine-containing reactant sources. In other embodiments, the one or more process gas inlets are coupled to one or more hydrogen-containing reactant sources or deuterium-containing reactant sources. In other embodiments, the one or more process gas inlets are coupled to one or more first precursor sources. In other embodiments, the one or more process gas inlets are coupled to one or more second precursor sources. In still other embodiments, the one or more process gas inlets are coupled to one or more third precursor sources. In other embodiments, the one or more process gas inlets are coupled to one or more halogen-containing reactant sources.

[0088] In some embodiments, the one or more controllers include machine-readable instructions for performing one or more cycles of the following operations: directing the one or more fluorine-containing reactants to a pre-cleaning chamber; transferring a substrate from the pre-cleaning chamber to an epitaxial chamber under vacuum (e.g., via a transfer module); directing one or more hydrogen-containing or deuterium-containing reactants to the epitaxial chamber; cyclically directing at least one of the one or more first precursors, second precursors, or optional third precursors to the epitaxial chamber; transferring the substrate out of the epitaxial chamber; and directing the one or more halogen-containing reactants to the epitaxial chamber.

[0089] In some embodiments, the one or more controllers further include machine-readable instructions for: generating plasma in a plasma source. In other embodiments, the one or more controllers further include machine-readable instructions for: generating plasma in the plasma source when directing the one or more fluorine-containing reactants to the pre-cleaning chamber. In still other embodiments, the one or more controllers further include machine-readable instructions for: generating plasma in the plasma source when directing the one or more hydrogen-containing, deuterium-containing, first precursor, second precursor, optional third precursor, or halogen-containing reactants to the epitaxial chamber.

[0090] In some embodiments, the one or more process gas inlets are coupled to the plasma source. In a further embodiment, the one or more process gas inlets coupled to the plasma source are also coupled to at least one of the one or more fluorine-containing reactant sources, hydrogen-containing reactant sources, or deuterium-containing reactant sources.

[0091] In some embodiments, the one or more process gas inlets are coupled to the at least one epitaxial chamber. In a further embodiment, the one or more process gas inlets coupled to the at least one epitaxial chamber are also coupled to at least one of the one or more first precursor sources, second precursor sources, optional third precursor sources, or halogen-containing reactant sources.

[0092] In a sixth aspect, the present disclosure encompasses a system or apparatus comprising: at least one pre-cleaning chamber; at least one pre-treatment chamber; at least one epitaxial chamber; a plasma source; at least one outlet coupled to a vacuum; one or more process gas inlets; and one or more controllers for controlling operations, wherein the one or more controllers include machine-readable instructions for performing one or more cycles of operations (e.g., any of those described herein) or for performing one or more methods (e.g., any of those described herein).

[0093] In some embodiments, the pre-cleaning chamber or pre-treatment chamber or epitaxial chamber includes a substrate support configured to support a substrate. In some embodiments, the substrate support is a pedestal or a chuck. In further embodiments, the system or apparatus includes a transfer module configured to transfer the substrate from the pre-treatment chamber to the pre-cleaning chamber (e.g., under vacuum), or a transfer module configured to transfer the substrate from the pre-cleaning chamber to the epitaxial chamber (e.g., under vacuum).

[0094] In some embodiments, the one or more process gas inlets are coupled to one or more fluorine-containing reactant sources. In other embodiments, the one or more process gas inlets are coupled to one or more hydrogen-containing reactant sources or deuterium-containing reactant sources. In other embodiments, the one or more process gas inlets are coupled to one or more first precursor sources. In other embodiments, the one or more process gas inlets are coupled to one or more second precursor sources. In other embodiments, the one or more process gas inlets are coupled to one or more optional third precursor sources. In some embodiments, the one or more process gas inlets are coupled to one or more halogen-containing reactant sources.

[0095] In some embodiments, the one or more controllers include machine-readable instructions for performing one or more cycles of the following operations: directing the one or more fluorine-containing reactants to the pre-cleaning chamber; transferring the substrate from the pre-cleaning chamber to the pre-treatment chamber under vacuum (e.g., via a transfer module); directing the one or more hydrogen-containing reactants or deuterium-containing reactants to the pre-treatment chamber; transferring the substrate from the pre-treatment chamber to the epitaxial chamber under vacuum (e.g., via a transfer module); cyclically directing at least one of the one or more first precursors, second precursors, or optional third precursors to the epitaxial chamber; removing the substrate from the epitaxial chamber (e.g., via a transfer module); and directing the one or more halogen-containing reactants to the epitaxial chamber.

[0096] In some embodiments, the one or more controllers include machine-readable instructions for performing at least one of the following: generating a plasma in a plasma source. In other embodiments, the one or more controllers include machine-readable instructions for: generating a plasma in a plasma source when guiding the one or more fluorine-containing reactants to a pre-cleaning chamber. In other embodiments, the one or more controllers include machine-readable instructions for: generating a plasma in a plasma source when guiding the one or more hydrogen-containing reactants or deuterium-containing reactants to a pre-treatment chamber. In other embodiments, the one or more controllers include machine-readable instructions for: generating a plasma in a plasma source when guiding at least one of the one or more first precursors, second precursors, or optional third precursors to an epitaxial chamber. In still other embodiments, the one or more controllers include machine-readable instructions for: generating a plasma in a plasma source when guiding the one or more halogen-containing reactants to an epitaxial chamber.

[0097] In some embodiments, the one or more process gas inlets are coupled to a plasma source. In other embodiments, the one or more process gas inlets coupled to the plasma source are further coupled to at least one of the one or more fluorine-containing reactant sources, hydrogen-containing reactant sources, or deuterium-containing reactant sources.

[0098] In some embodiments, the one or more process gas inlets are coupled to the at least one epitaxial chamber. In other embodiments, the one or more process gas inlets coupled to the at least one epitaxial chamber are further coupled to at least one of the one or more first precursor sources, second precursor sources, optional third precursor sources, or halogen-containing reactant sources.

[0099] In any embodiment herein, the energetic species include at least one of free radicals, plasma-generated free radicals, metastable species, plasma-generated metastable species, ions, plasma-generated ions, neutral species, plasma-generated neutral species, plasma, photons, radiation, excited molecules, excited atoms, or other species described herein.

[0100] In any embodiment herein, the free radicals include plasma-generated free radicals. In some embodiments, the free radicals or plasma-generated free radicals include at least one of hydrogen-containing free radicals, deuterium-containing free radicals, nitrogen-containing free radicals, or the like.

[0101] In any embodiment herein, the metastable species include plasma-generated metastable species. In some embodiments, the metastable species or plasma-generated metastable species include at least one of helium-containing metastable species, argon-containing metastable species, or the like.

[0102] In any embodiment herein, a high-energy species (e.g., at least one of a radical or a metastable species) is generated by a plasma. Non-limiting examples of plasmas include capacitively coupled plasmas (CCPs), inductively coupled plasmas (ICPs), transformer coupled plasmas (TCPs), electron cyclotron resonance (ECR) plasmas, surface wave plasmas (SWPs), plasmas generated using SWP (e.g., a radial line slot antenna (RLSA)), microwave plasmas (MWPs), plasmas generated using ultraviolet (UV) radiation, low energy plasmas (LEPs), low temperature plasmas (LTPs), and the like. Non-limiting examples of plasma sources include beam sources, line sources, or pixelated sources.

[0103] In any embodiment herein, a source gas is used to generate the plasma. In some embodiments, the source gas includes at least one of a hydrogen-containing gas, a deuterium-containing gas, a nitrogen-containing gas, or an inert gas (e.g., a helium-containing gas, an argon-containing gas, or another inert gas). Other non-limiting source gases are described herein, and mixtures of any source gases may be employed.

[0104] In any embodiment herein, at least the first layer includes a semiconductor layer (e.g., a first semiconductor layer). In other embodiments, at least the second layer includes a semiconductor layer (e.g., a second semiconductor layer). In still other embodiments, the first layer includes a first semiconductor layer and the second layer includes a second semiconductor layer.

[0105] In any embodiment herein, the first layer (e.g., the first semiconductor layer) and the second layer (e.g., the second semiconductor layer) have different etching behaviors. In some embodiments, the ratio of the etching rate of the first layer to the etching rate of the second layer is greater than about 2:1, 5:1, 10:1, 25:1, 20:1, or 100:1. In other embodiments, the ratio of the etching rate of the second layer to the etching rate of the first layer is greater than about 2:1, 5:1, 10:1, 25:1, 20:1, or 100:1.

[0106] In any embodiment herein, the temperature during deposition of the first layer is different from the temperature during deposition of the second layer.

[0107] In any embodiment herein, the layer (e.g., the first semiconductor layer or the second semiconductor layer) includes a sacrificial layer.

[0108] In any embodiment herein, the deposition rate associated with depositing at least one of the first layer or the second layer is at least about 3 nanometers per minute (nm / min). In other embodiments, the deposition rate associated with depositing at least one of the first layer or the second layer is at least about 30 nm / min.

[0109] In any embodiment herein, a high-energy species (e.g., at least one of a radical or a metastable species) is generated in a remote plasma source disposed upstream of a reaction chamber (e.g., an epitaxial chamber).

[0110] In any embodiment herein, a high-energy species (e.g., at least one of a radical or a metastable species) is generated in-situ in a portion of the reaction chamber.

[0111] In any embodiment herein, the first precursor includes a silicon-containing precursor (Si precursor). Examples include silanes, hydrosilanes, or silicides. Non-limiting examples of precursors include silane (SiH4), disilane (Si2H6), trisilane (Si3H8), cyclotrisilane (Si3H6), tetrasilane (Si4H 10 )), cyclotetrasilane (Si4H8), pentasilane (Si5H 12 )), cyclopentasilane (Si5H 10 )), hexasilane (Si6H 14 )), cyclohexasilane (Si6H 12 )), heptasilane (Si7H 16 )), cycloheptasilane (Si7H 14 )), octasilane (Si8H 18 )), monochlorosilane (MCS, SiH3Cl), dichlorosilane (DCS, SiH2Cl2), trichlorosilane (TCS, SiHCl3), 1,2-dichloro-disilane (Si2H4Cl2), 1,2,3-trichlorosilane (Si3H5Cl3), silicon tetrachloride (STC, SiCl4), hexachloro-disilane (HCDS, Si2Cl6), octachloro-trisilane (OCTS, Si3Cl8), and methylgermylsilane (H3Ge-SiH3), and any one of those described herein. Any such precursor may contain one or more hydrogen atoms substituted by deuterium.

[0112] In any embodiment herein, the second precursor includes a germanium-containing precursor (Ge precursor) or a silicon-germanium-containing precursor (SiGe precursor). Examples include germanes, hydrogermanes, germanides, or silicon-germanium-hydrogen precursors. Non-limiting examples of precursors include germane (GeH4), digermane (Ge2H6)), trigermane (Ge3H8), tetragermane (Ge4H 10 )), pentagermane (Ge5H 12 )), dichlorogermane (GeH2Cl2), trichlorogermane (GeHCl3), germanium tetrachloride (GeCl4), and hexachloro-digermane (Ge2Cl6), and any one of those described herein. Any such precursor may contain one or more hydrogen atoms.

[0113] In any embodiment herein, the third precursor comprises a Si precursor. Examples include silanes, silane halides, or silicon halides. Non-limiting examples of precursors include silane (SiH4), disilane (Si2H6), trisilane (Si3H8), cyclotrisilane (Si3H6), tetrasilane (Si4H 10 ), cyclotetrasilane (Si4H8), pentasilane (Si5H 12 ), cyclopentasilane (Si5H 10 ), hexasilane (Si6H 14 ), cyclohexasilane (Si6H 12 ), heptasilane (Si7H 16 ), cycloheptasilane (Si7H 14 ), octasilane (Si8H 18 ), monochlorosilane (MCS, SiH3Cl), dichlorosilane (DCS, SiH2Cl2), trichlorosilane (TCS, SiHCl3), 1,2-dichloro-disilane (Si2H4Cl2), 1,2,3-trichlorosilane (Si3H5Cl3), silicon tetrachloride (STC, SiCl4), hexachlorodisilane (HCDS, Si2Cl6), octachlorotrisilane (OCTS, Si3Cl8), and methylgermylsilane (H3Ge-SiH3), and any of those described herein. Any such precursor may contain one or more hydrogen atoms substituted with deuterium.

[0114] In any embodiment herein, the first layer comprises a silicon-containing layer (Si layer), and the second layer comprises a silicon and germanium-containing layer (SiGe layer). In other embodiments, the first layer comprises a silicon and germanium-containing layer (SiGe layer), and the second layer comprises a silicon-containing layer (Si layer). In a particular embodiment, the germanium concentration within the layer (e.g., within at least one of the first or second layers) is about 10 atomic % to 50 atomic %, and other ranges as described herein.

[0115] In any embodiment herein, the predetermined number of layers is at least 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 or more layers.

[0116] In any embodiment herein, the predetermined number of layers includes a plurality of first layers (e.g., first semiconductor layers) within the stack. In some embodiments, the thickness of at least one first layer may be the same as or different from the thickness of another first layer within the stack.

[0117] In any embodiment herein, the predetermined number of layers includes a plurality of second layers (e.g., second semiconductor layers) within the stack. In some embodiments, the thickness of at least one second layer may be the same as or different from the thickness of another second layer within the stack.

[0118] In any embodiment herein, the predetermined number of layers includes a plurality of alternating first and second layers (e.g., alternating first and second semiconductor layers) within the stack. In some embodiments, the thickness of at least one first layer may be the same as or different from the thickness of another first layer within the stack. In other embodiments, the thickness of at least one second layer may be the same as or different from the thickness of another second layer within the stack.

[0119] In any embodiment herein, the heterolayer forms a strained semiconductor structure. In certain embodiments, at least one of the heterolayer, the first layer, or the second layer is an epitaxial layer. In other embodiments, each of the heterolayer, the first layer, and the second layer is an epitaxial layer.

[0120] In any embodiment herein, the layer has a thickness of about 5 nm to 60 nm. In other embodiments, the layer (e.g., the first semiconductor layer or the second semiconductor layer, such as any of those described herein) has a thickness of about 5 nm to 60 nm, 5 nm to 50 nm, 5 nm to 25 nm, 5 nm to 20 nm, 5 nm to 10 nm, 10 nm to 60 nm, 10 nm to 50 nm, 10 nm to 25 nm, or 10 nm to 20 nm.

[0121] In any embodiment herein, the substrate has at least one of a pre-cleaned surface, a pre-treated surface, or a pre-cleaned and pre-treated surface.

[0122] In any embodiment herein, the reaction chamber includes an epitaxial chamber.

[0123] In any embodiment herein, the reaction chamber is at least one of cleaned or treated.

[0124] In any embodiment herein, the surface of the device or system (e.g., the surface of the reaction chamber, the epitaxial chamber, the energy source, the window of the energy source, the pedestal, the chuck, or a portion of any of these) includes a coating. In certain embodiments, the coating is configured to be resistant to damage or etching caused by the reactor cleaning or reactor treatment operations described herein.

[0125] In any embodiment herein, at least one of pre-cleaning, pre-treatment, epitaxial deposition, and reactor cleaning is independently performed at a temperature below about 900 °C, 800 °C, 750 °C, 700 °C, 650 °C, 600 °C, 550 °C, or 500 °C; or at a temperature of about 400 °C to 900 °C or at a temperature of about 400 °C to 700 °C.

[0126] In any embodiment herein, pre-cleaning, pre-treatment, epitaxial deposition, and reactor cleaning are each independently performed at a temperature below about 900 °C, 800 °C, 750 °C, 700 °C, 650 °C, 600 °C, 550 °C, or 500 °C; or at a temperature of about 400 °C to 900 °C or at a temperature of about 400 °C to 700 °C.

[0127] In any embodiment herein, the method includes epitaxially depositing one or more layers (e.g., semiconductor layers). In some embodiments, epitaxial deposition includes providing a plurality of alternating first and second layers. In certain embodiments, the plurality of layers includes more than 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, or more pairs, where each pair includes a single first layer and a single second layer. In other embodiments, the plurality of layers includes more than 1, 2, 3, 4, 5, or more quadruples, where each quadruple includes two first layers and two second layers. In still other embodiments, the plurality of layers includes more than 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, or more individual layers, where each individual layer can be a first layer or a second layer.

[0128] In any embodiment herein, the method includes atomic layer deposition (ALD), plasma-enhanced ALD (PEALD), chemical vapor deposition (CVD), plasma-enhanced CVD (PECVD), or remote plasma CVD (RPCVD). In certain embodiments, the method includes an operation (e.g., at least one of operation (a) or operation (b)), where the operation includes ALD, PEALD, CVD, PECVD, or RPCVD. In other embodiments, the operation (e.g., at least one of operation (a) or operation (b)) is cyclically repeated. For example, for operation (a) of flowing a first precursor into the reaction chamber, the first precursor flow can be introduced into the chamber for a number of n cycles, with optional purge cycles therebetween.

[0129] In any embodiment herein, the method, apparatus, or system further includes a showerhead. In some instances, the showerhead is disposed within the reaction chamber. In other instances, the showerhead includes a coating (e.g., any of those described herein). In some embodiments, the showerhead is configured to be cooled. In still other embodiments, the showerhead includes a plurality of holes arranged in a non-uniform pattern (e.g., a pattern including an increasing number of holes with increasing radius).

[0130] In any embodiment herein, the method further includes (e.g., after deposition): surface pre-treatment of at least one of the first layer or the second layer.

[0131] In any embodiment herein, the method further includes (e.g., after reactor cleaning): reactor treatment by passivating the environment or surface within the epitaxial chamber. In some embodiments, passivation includes delivering a hydrogen-containing plasma to the epitaxial chamber. Additional embodiments are described herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0132] Figure 1A-1E Schematic diagrams are provided of (A) non-limiting stack 100, (B) non-limiting layer pair 106, (C) non-limiting layer quadruple 107, (D) another non-limiting stack 150, and (E) yet another non-limiting stack 151.

[0133] Figure 2A-2I Flowcharts are provided respectively of (A-G) non-limiting methods 200A - 200G, (H) a schematic diagram of non-limiting system 250, and (I) a schematic diagram of another non-limiting system 290.

[0134] Figure 3A-3E Flowcharts are provided of (A) non-limiting method 300, (B) another non-limiting method 350, (C) a process timing diagram of non-limiting method 360, (D) a process timing diagram of another non-limiting method 390, and (E) a flowchart of another non-limiting method 3000.

[0135] Figure 4A-4C Flowcharts are provided of (A) non-limiting method 400, (B) another non-limiting method 450, and (C) a process timing diagram of non-limiting method 460.

[0136] Figure 5 A schematic diagram of an exemplary processing station 500 for performing the disclosed embodiments is provided.

[0137] Figure 6 A schematic diagram of an exemplary processing tool 600 for performing the disclosed embodiments is provided.

[0138] Figure 7A-7BSchematic diagrams showing exemplary apparatuses 700a, 700b including capacitively coupled plasma (CCP) reactors are shown.

[0139] Figure 8A-8B Schematic diagrams showing exemplary multi-station processing tools 800a, 800b implementing the disclosed embodiments are shown.

[0140] Figure 9 Schematic diagram of another exemplary processing station 900 for implementing the disclosed embodiments.

[0141] Figure 10 Schematic diagram of another exemplary processing tool 1000 for implementing the disclosed embodiments.

[0142] Figure 11 Schematic diagram of another exemplary processing station 1100 for implementing the disclosed embodiments.

[0143] Figure 12 Schematic diagram of an exemplary plasma processing apparatus 1200 having a remote plasma source according to some implementations.

[0144] Figure 13 Schematic diagram of another exemplary processing station 1300 for implementing the disclosed embodiments.

[0145] Figure 14 Schematic diagram of an exemplary plasma processing apparatus 1400 having a remote plasma source according to some implementations. Detailed Description

[0146] Reference is made in detail herein to specific embodiments of the present disclosure. Examples of specific embodiments are shown in the accompanying drawings. Although the present disclosure will be described in conjunction with these specific embodiments, it is to be understood that it is not intended to limit the present disclosure to these specific embodiments. On the contrary, it is intended to cover alternatives, modifications, and equivalents that may be included within the spirit and scope of the present disclosure. In the following description, numerous specific details are set forth to provide a thorough understanding of the present disclosure. The present disclosure may be practiced without some or all of these specific details. In other instances, well-known process operations are not described in detail so as not to unnecessarily obscure the present disclosure.

[0147] The following disclosed implementations describe the deposition of materials on a substrate (e.g., a wafer, a substrate, or other workpiece). The workpiece may have various shapes, sizes, and materials. In this application, the terms "semiconductor wafer", "wafer", "substrate", "wafer substrate", and "partially fabricated integrated circuit" may be used interchangeably. The substrate may have any useful characteristics, such as a diameter greater than about 150 mm, 200 mm, 300 mm, 450 mm, or larger.

[0148] The present disclosure generally relates to the field of vertical stacks, and methods of manufacturing such stacks and apparatuses for implementing such methods. For example, a vertical stack may include heterolayers. A heterolayer may be defined as those layers present in a vertical stack where a first layer is disposed below a second layer. In one example, the first layer and the second layer are composed of different materials. Such heterolayers may be epitaxial or non-epitaxial. As used herein, a "heterolayer" means that the overlying layer is formed of a material different from that of the underlying layer. For example, the difference may include the presence or absence of at least one different atom, bond, or other chemical or material property in the overlying layer compared to the underlying layer. Another difference may include a different amount of at least one different atom, bond, or other chemical or material property in the overlying layer compared to the underlying layer.

[0149] In one embodiment, the first layer comprises or consists of silicon (Si), and the second layer comprises non-silicon atoms or a combination of Si and non-silicon atoms. In another embodiment, the first layer comprises non-silicon atoms or a combination of Si and non-silicon atoms, and the second layer comprises or consists of Si. Non-limiting examples of non-silicon atoms include germanium (Ge), oxygen (O), nitrogen (N), carbon (C), phosphorus (P), boron (B), and combinations thereof. In a particular embodiment, the stack includes a plurality of alternating first and second layers.

[0150] In some non-limiting embodiments, the vertical stack includes a plurality of alternating first and second layers (e.g., a first semiconductor layer and a second semiconductor layer). In a particular embodiment, the vertical stack includes n1 first semiconductor layers and n2 second semiconductor layers, where n1 + n2 > 4 (e.g., having more than 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 or more layers). In some embodiments, the vertical stack includes more than 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or more pairs of layers (e.g., where a pair includes a single first semiconductor layer and a single second semiconductor layer, and such pairs are further described herein). In other embodiments, the vertical stack includes more than 1, 2, 3, 4, 5 or more quadruple layers (e.g., where the pairs in a quadruple include a first semiconductor layer, a second semiconductor layer, another first semiconductor layer, and another second semiconductor layer; and such quadruples are further described herein).

[0151] In certain embodiments of any stack in this disclosure, each layer is typically an epitaxial crystalline layer having any useful thickness, e.g., the thickness of each of the first or second semiconductor layers is about 5 nm to 30 nm. Within the stack, each first semiconductor layer can have the same thickness or different thicknesses. Similarly, each second semiconductor layer can have the same thickness or different thicknesses. In other embodiments, at least one of the first or second semiconductor layers is a non-epitaxial layer. In still other embodiments, at least one of the first or second semiconductor layers is a crystalline layer, semi-crystalline layer, polycrystalline layer, or amorphous layer.

[0152] In some embodiments, a vertical stack includes a first semiconductor layer and a second semiconductor layer, where the first and second semiconductor layers are different. As used herein, "semiconductor layer" refers to a layer formed of a material employed in semiconductor processing. Non-limiting materials can include any of those described herein, including materials having group III atoms, group IV atoms, group V atoms, and combinations thereof (e.g., IV-IV materials, such as materials having a first group IV atom and a second group IV atom different from the first group IV atom). Additional other materials can include group I (e.g., copper (Cu), silver (Ag), or gold (Au)), group II (e.g., zinc (Zn), cadmium (Cd), or mercury (Hg)), group III (e.g., boron (B), aluminum (Al), gallium (Ga), indium (In), or thallium (Tl)), group IV (e.g., carbon (C), silicon (Si), germanium (Ge), tin (Sn), or lead (Pb)), group V (e.g., nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb), or bismuth (Bi)), group VI (e.g., oxygen (O), sulfur (S), selenium (Se), or tellurium (Te)), and group VII atoms (e.g., fluorine (F), chlorine (Cl), bromine (Br), or iodine (I)) and combinations thereof (e.g., I-III-VI materials having at least one group I atom, at least one group III atom, and at least one group VI atom; II-VI materials having at least one group II atom and at least one group VI atom; II-V materials having at least one group II atom and at least one group V atom; I-VII materials having at least one group I atom and at least one group VII atom; III-V materials having at least one group III atom and at least one group V atom; IV-VI materials having at least one group IV atom and at least one group VI atom; V-VI materials having at least one group V atom and at least one group VI atom; oxides, nitrides, carbides, oxynitrides, carbon oxides, carbonitrides, and the like).

[0153] In some embodiments, the layers of the stack contain alloys and elements that are only from Group IV of the Periodic Table. In some examples, one or more layers of the stack mainly comprise one or more Group IV elements and a small amount (e.g., about 1 atomic % or less) of one or more Group III or Group V elements as dopants. In other examples, one or more layers of the stack mainly comprise one or more Group IV elements and a small amount (e.g., about 1 atomic % or less) of one or more Group III and Group V elements as dopants.

[0154] In certain embodiments, the first semiconductor layer has an etching behavior different from that of the second semiconductor layer. In some embodiments, the first semiconductor layer is selectively etched compared to the second semiconductor layer. In other embodiments, the second semiconductor layer is selectively etched compared to the first semiconductor layer. In certain embodiments, the ratio of the etching rate of the first semiconductor layer to the etching rate of the second semiconductor layer is greater than about 2:1, 5:1, 10:1, 25:1, 20:1, or 100:1. In other embodiments, the ratio of the etching rate of the second semiconductor layer to the etching rate of the first semiconductor layer is greater than about 2:1, 5:1, 10:1, 25:1, 20:1, or 100:1. Additional details regarding the etching differences are described herein.

[0155] In some embodiments, the vertical stack includes a plurality of epitaxial layers. As used herein, an "epitaxial layer" refers to a layer formed by epitaxy, as described herein. In some embodiments, each of the first and second semiconductor layers includes an epitaxial layer having any useful thickness or thickness range. In other embodiments, the first semiconductor layer includes an epitaxial layer; and the second semiconductor layer includes an epitaxial layer or a non-epitaxial layer. In some embodiments, at least one of the first or second semiconductor layers includes a crystalline layer, a semi-crystalline layer, or a polycrystalline layer.

[0156] In some embodiments, the vertical stack includes a semiconductor layer (e.g., as the first semiconductor layer) and a sacrificial layer (e.g., as the second semiconductor layer). As used herein, a "sacrificial layer" is a layer that can be removed or etched using semiconductor processing. In one embodiment, the sacrificial layer can be removed using selective etching. Such sacrificial layers can be formed from any of the materials described herein, e.g., semiconductor materials.

[0157] In certain embodiments, the semiconductor layer can serve as the channel layer of a transistor in a memory array. As used herein, a "channel layer" is a layer configured to transport electrical charge carriers, electrons, or holes. An insulating layer can be employed adjacent to the channel (e.g., as described herein, such as in paragraph

[0159] ).

[0158] In some embodiments, the vertical stack includes a plurality of alternating semiconductor layers and sacrificial layers. In some embodiments, the semiconductor layers include epitaxial layers having any useful thickness or thickness range. In one example, the vertical stack may include a plurality of semiconductor layers, and the thickness of each semiconductor layer within the stack may be the same or different. In some embodiments, the sacrificial layers include epitaxial layers or non-epitaxial layers. In some embodiments, the sacrificial layers include crystalline layers, semi-crystalline layers, or polycrystalline layers.

[0159] In some embodiments, the vertical stack includes epitaxially grown alternating semiconductor layers. In other embodiments, after additional processing, one of these layers may become the channel, and the other layer may be sacrificial. During subsequent processing, the sacrificial layer may be removed and replaced with an insulating layer to isolate the channel. Examples of materials for the channel or channel layer may include silicon-containing materials (e.g., in Si layers or SiGe layers). Any channel material may further include one or more dopants, such as phosphorus (P), boron (B), carbon (C), tin (Sn), arsenic (As), and the like. Examples of materials for the insulating layer include insulating materials or dielectric materials, such as silicon nitride, silicon oxide, silicon oxynitride, silicon carbide, silicon oxycarbide, silicon carbonitride, oxynitride, oxycarbide, carbonitride, or doped forms thereof (e.g., silicon carbide doped with at least one of oxygen or nitrogen).

[0160] In certain embodiments, the vertical stack includes alternating layers of silicon-containing layers (Si layers) and silicon and germanium-containing layers (SiGe layers). In some non-limiting embodiments, the vertical stack includes a plurality of alternating Si layers and SiGe layers (e.g., more than 4 layers, more than 2 pairs of layers, or more than 1 quadruple layer). In certain embodiments, each layer is typically an epitaxial crystalline layer having any useful thickness, such as each Si layer or each SiGe layer having a thickness of about 5 - 20 nm. Within the stack, each Si layer may have the same thickness or different thicknesses. Similarly, each SiGe layer may have the same thickness or different thicknesses. In other embodiments, at least one of the Si layers or SiGe layers is a non-epitaxial layer. In still other embodiments, the Si layers or SiGe layers are crystalline layers, semi-crystalline layers, polycrystalline layers, or amorphous layers.

[0161] Figure 1A A non-limiting stack 100 is shown disposed on an optional buffer layer 120, which in turn is disposed on the top surface of a substrate 110. In certain embodiments, the buffer layer is an epitaxial layer or is deposited epitaxially. In other embodiments, there is no buffer layer.

[0162] The stack may include alternating layers of a first layer and a second layer. Here, stack 100 includes a number n1 of first semiconductor layers 130a-n and a number n2 of second semiconductor layers 135a-n, where n1 and n2 are integers. In some embodiments, n1 = n2. In other embodiments, n1 < n2, or n1 > n2. Each layer may have a thickness t, where the respective t of each of the first semiconductor layers 130a-n and the second semiconductor layers 135a-n may be the same or different. The stack may be characterized by having a pair 105 of first and second semiconductor layers, where the stack has a number x of first-second semiconductor pairs. x, n1, and n2 are each independently selected from 1 to 100 (e.g., 2 to 100, 3 to 100, 4 to 100, 5 to 100, 6 to 100, 7 to 100, 8 to 100, 9 to 100, 10 to 100, 1 to 50, 2 to 50, 3 to 50, 4 to 50, 5 to 50, 6 to 50, 7 to 50, 8 to 50, 9 to 50, 10 to 50, and the like).

[0163] In a particular embodiment, x = n1 = n2. For example, the stack may have 10 pairs (x = 10), where each pair includes a single first layer and a single second layer; thus, 10 first layers (n1 = 10) and 10 second layers (n2 = 10) are provided within the stack. In other embodiments, x < n1, n2, for example when the stack has 10 pairs (x = 10); but the stack further has an additional first layer before the first pair (close to the substrate or close to the bottom of the stack) or an additional first layer after the first pair (close to the hard mask or close to the top of the stack). Thus, in some instances, a portion of the stack may be composed of repeating layers (e.g., provided as repeating pairs), while another portion of the stack may include non-repeating layers.

[0164] Optionally, the stack may have a hard mask 140 or a metal layer disposed thereon. In a particular embodiment, the hard mask is not an epitaxial layer or not deposited epitaxially.

[0165] As Figure 1B shown, the stack may include a number n1 of first semiconductor layers 131a-n and a number n2 of second semiconductor layers 136a-n, where n1 and n2 are integers. In some embodiments, n1 = n2. In other embodiments, n1 < n2, or n1 > n2. Each layer may have a thickness, which may be the same or different within the stack. As Figure 1BAs shown, the stack may include a first semiconductor layer 131b having a thickness t1 and a second semiconductor layer 136b having a thickness t2. In some embodiments, t1 < t2, or t1 > t2. In other embodiments, t1 = t2. Even within the stack, the respective t1's associated with each of the first semiconductor layers 131a-n may be different or the same. Similarly, the respective t2's associated with each of the second semiconductor layers 136a-n may be different or the same.

[0166] As Figure 1B shown, the stack may be characterized by having a first and a second semiconductor layer of a pair 106, wherein the stack has a number x of first-second semiconductor pairs, a number n1 of first semiconductor layers 131a-n, and a number n2 of second semiconductor layers 136a-n. x, n1, and n2 are each independently selected from 1 to 100 (e.g., 2 to 100, 3 to 100, 4 to 100, 5 to 100, 6 to 100, 7 to 100, 8 to 100, 9 to 100, 10 to 100, 1 to 50, 2 to 50, 3 to 50, 4 to 50, 5 to 50, 6 to 50, 7 to 50, 8 to 50, 9 to 50, 10 to 50, and the like). In some embodiments, the stack includes more than 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 25, 30, 35, 40, 45, 50, or more pairs. In other embodiments, a portion of the stack may be composed of repeating pairs, and another portion of the stack may include non-repeating layers.

[0167] In addition to pairs, the stack may include triplets, quadruplets, or any other useful repeating group of layers of number y (e.g., where y is 2, 3, 4, 5, 6, or more). In the case of a pair having y = 2 layers (a single first semiconductor layer and a single second semiconductor layer), a quadruplet may have y = 4 layers (a first semiconductor layer, followed by a second semiconductor layer, another first semiconductor layer, and finally another second semiconductor layer).

[0168] As Figure 1CAs shown, the stack features may include first and second semiconductor layers with a quadruple 107, where the stack has a number x of first-second-first-second semiconductor quadruples, a number n1a of first semiconductor layers 132a-n, a number n1b of additional first semiconductor layers 133a-n, a number n2a of second semiconductor layers 137a-n, and a number n2b of additional second semiconductor layers 138a-n. x, n1a, n1b, n2a, and n2b are each independently selected from 1 to 100 (e.g., 2 to 100, 3 to 100, 4 to 100, 5 to 100, 6 to 100, 7 to 100, 8 to 100, 9 to 100, 10 to 100, 1 to 50, 2 to 50, 3 to 50, 4 to 50, 5 to 50, 6 to 50, 7 to 50, 8 to 50, 9 to 50, 10 to 50, and the like). In some embodiments, the stack includes more than 1, 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, or more quadruples. In other embodiments, a portion of the stack may be composed of repeating quadruples, while another portion of the stack may include non-repeating layers.

[0169] The quadruple may include a first semiconductor layer 132b with a thickness t1, a second semiconductor layer 137b with a thickness t2, another first semiconductor layer 133b with a thickness t3, and another second semiconductor layer 138b with a thickness t4. In some embodiments, t1 ≤ t2, t1 ≥ t2, t1 ≤ t3, t1 ≥ t3, t1 ≤ t4, t1 ≥ t4, t2 ≤ t3, t2 ≥ t3, t2 ≤ t4, t2 ≥ t4, t3 ≤ t4, or t3 ≥ t4. In other embodiments, t1 ≤ t3, t1 ≥ t3, t2 ≤ t4, and t2 ≥ t4. In still other embodiments, t1 = t2 = t3 = t4. Even within the stack, the respective t1 or t3 associated with each of the first semiconductor layers 132a-n / 133a-n may be different or the same. Similarly, the respective t2 or t4 associated with each of the second semiconductor layers 137a-n / 138a-n may be different or the same. The quadruple 107 may be repeated to form a stack. In certain embodiments, the thicknesses within the top or bottom of the stack may be the same or different (e.g., considering different etching rates or deposition rates, which may depend on whether the layer is towards the top or bottom of the stack).

[0170] In some embodiments, the stack may include a silicon-containing layer (Si layer) and a silicon-germanium-containing layer (SiGe layer). Figure 1D A non-limiting stack 150 is shown disposed on an optional buffer layer 170, which in turn is disposed on the top surface of a substrate 160. In certain embodiments, the buffer layer is an epitaxial layer or deposited epitaxially.

[0171] Here, the stack 150 includes a number n1 of SiGe layers 180a-n and a number n2 of Si layers 185a-n, where n1 and n2 are integers. In some embodiments, n1 = n2. In other embodiments, n1 < n2, or n1 > n2. Each layer may have a thickness t, where the respective t of each of the SiGe layers 180a-n and the Si layers 185a-n may be the same or different. The stack may be characterized as having a pair 155 of SiGe-Si layers, where the stack has a number x of SiGe-Si pairs. x, n1, and n2 are each independently selected from 1 to 100 (e.g., 2 to 100, 3 to 100, 4 to 100, 5 to 100, 6 to 100, 7 to 100, 8 to 100, 9 to 100, 10 to 100, 1 to 50, 2 to 50, 3 to 50, 4 to 50, 5 to 50, 6 to 50, 7 to 50, 8 to 50, 9 to 50, 10 to 50, and the like).

[0172] Optionally, the stack may have a hard mask 190 or a metal layer disposed thereon. In certain embodiments, the hard mask is not an epitaxial layer or deposited epitaxially. Non-limiting materials for the hard mask (e.g., an ashing-capable hard mask) or the metal layer include silicon (e.g., silicon oxide, silicon nitride, silicon oxynitride, silicon carbon oxide, silicon carbide, etc.), carbon (e.g., amorphous carbon or amorphous carbon-hydrogen), nitrogen, oxygen, aluminum (Al), nitrides (e.g., titanium nitride (TiN), tantalum nitride (TaN), or tungsten nitride (WN)), metals (e.g., cobalt (Co), nickel (Ni), ruthenium (Ru), tin (Sn), indium (In), palladium (Pd), germanium (Ge), titanium (Ti), tungsten (W), chromium (Cr)), copper (Cu), tantalum (Ta), and combinations thereof), metal oxides (e.g., oxides of any of the metals described herein, including titanium oxide, titanium silicon oxide, tungsten oxide, or tantalum oxide), and any other materials described herein. Any of these materials may be provided as a layer adjacent to the hard mask, such as a seed layer, an anti-reflective coating, a liner layer, an adhesion layer, and the like.

[0173] In some embodiments, the order of the layers within the pair or quadruple may be modified. Figure 1EIllustrated is a non-limiting stack 151 having a heterolayer disposed on the top surface of a substrate 161. Here, stack 151 includes an Si layer 186a disposed directly on the top surface of substrate 161. Additionally, stack 151 includes a number n1 of Si layers 186a-n and a number n2 of SiGe layers 181a-n, where n1 and n2 are integers. In some embodiments, n1 = n2. In other embodiments, n1 < n2, or n1 > n2. Each layer may have a thickness t, where the respective t of each of Si layers 186a-n and SiGe layers 181a-n may be the same or different. The stack may be characterized by having a pair 156 of Si-SiGe layers, where the stack has a number x of Si-SiGe pairs. x, n1, and n2 are each independently selected from 1 to 100 (e.g., 2 to 100, 3 to 100, 4 to 100, 5 to 100, 6 to 100, 7 to 100, 8 to 100, 9 to 100, 10 to 100, 1 to 50, 2 to 50, 3 to 50, 4 to 50, 5 to 50, 6 to 50, 7 to 50, 8 to 50, 9 to 50, 10 to 50, and the like). Optionally, the stack may have a hard mask 191 or a metal layer disposed thereon. In certain embodiments, the hard mask is not an epitaxial layer or deposited epitaxially.

[0174] The heterolayer may be provided within the stack in any useful manner. In one example, the heterolayer is deposited to minimize defects within the layer. In some embodiments, the stack may be prepared to minimize interdiffusion of atoms between the heterolayers. Other characteristics of the stack and the layer and methods thereof are described herein.

[0175] Figure 2A Non-limiting schematic diagrams are provided for providing a stack, forming a heterolayer within a stack, or depositing a film. In one embodiment, the method may include a plurality of operations. As shown, a non-limiting method 200 includes a variety of optional and required operations. Figure 2B-2G Methods are shown for performing the select operations in different combinations.

[0176] As Figure 2A shown, method 200A may include an optional operation 205 of performing an ex-situ cleaning of the substrate. Such ex-situ cleaning operation 205 may include a wet process or a dry process, such as any of those described herein with reference to a pre-cleaning operation 210 or a reactor cleaning operation 240. In one embodiment, the ex-situ cleaning operation 205 may remove metals or other contaminants from the surface of the substrate.

[0177] The method may further include an optional operation 210 of pre-cleaning the substrate surface and an optional operation 220 of pre-treating the substrate surface. Such optional operations (e.g., at least one of operations 210 or 220) may be configured to provide a pristine surface on which an epitaxial layer can be deposited. In certain embodiments, the pre-cleaning operation 210 is configured to remove native oxides on the substrate surface, and the operation 220 is configured to provide a pristine surface prior to epitaxial deposition.

[0178] As used herein, in some embodiments, the term "pre-clean" (preclean or precleaning) refers to a process of cleaning the substrate surface. In certain non-limiting embodiments, such pre-cleaning may provide an oxide-free surface on the substrate. In other non-limiting embodiments, such pre-cleaning may be configured to remove native oxides located on the substrate surface.

[0179] As used herein, in some embodiments, the term "pre-treat" (pretreat, pretreating, or pretreatment) refers to a process of treating the substrate surface. In certain non-limiting embodiments, such pre-treatment may remove contaminants (e.g., oxygen, carbon, fluorine, and the like) located on the substrate surface, where such contaminants may be present on the surface after pre-cleaning but prior to deposition. In other non-limiting embodiments, such pre-treatment may provide a passivated surface on the substrate. In still other non-limiting embodiments, such pre-treatment may provide a hydrophobic surface on the substrate. As used herein, a "hydrophobic surface" refers to a surface that repels water or water vapor. In one implementation, a hydrophobic surface is characterized by having at least one of Si-H, Si-D, and Si-F bonds. In another embodiment, a hydrophobic surface is characterized by having substantially all or at least 90% of the surface presenting at least one of Si-H, Si-D, or Si-F bonds. In another embodiment, a hydrophobic surface is characterized by having at least 95% of the surface presenting at least one of Si-H, Si-D, or Si-F bonds. In another embodiment, a hydrophobic surface is characterized by having a static water contact angle θ greater than about 90° for a liquid (water) provided at the test surface, where θ is measured between the surface-liquid interface and the liquid-vapor interface.

[0180] In some embodiments, operation 210 may be configured to pre-clean the substrate surface to remove oxides. Non-limiting pre-clean operations are described herein. In one embodiment, operation 210 may include delivering a halogen-containing reagent, a fluorine-containing vapor, or a fluorine-containing plasma to a reaction chamber containing the substrate. Without wishing to be bound by mechanism, fluorine atoms may react with oxygen atoms provided in the form of silicon oxide on the substrate surface, thereby producing fluorine-containing by-products. Such by-products may then be pyrolyzed, sublimed, evaporated, or otherwise removed from the surface. Operation 210 may include a dry process, a wet process, or a combination of dry and wet processes; non-limiting examples of such processes are further described herein. Such operation 210 may be performed in the absence or presence of a plasma.

[0181] In some embodiments, operation 220 may be configured to pre-treat the substrate surface to provide a pre-treated surface (e.g., a hydrophobic surface). Non-limiting pre-treatment operations are described herein. In one embodiment, operation 220 may include delivering a hydrogen-containing reagent, a deuterium-containing reagent, hydrogen gas, deuterium gas, a hydrogen-containing plasma, or a deuterium-containing plasma to a reaction chamber containing the substrate. In a particular embodiment, the reaction chamber containing the substrate is an epitaxial chamber. In this manner, epitaxial deposition may be performed using the pre-treatment without further moving the substrate. Operation 220 may include a dry process in the absence or presence of a plasma. Non-limiting examples of the pre-treatment process are further described herein.

[0182] Returning again to Figure 2A , method 200A may further include forming a heterostructure layer on the substrate by operation 230 of depositing one or more epitaxial layers. These layers may include one or more first semiconductor layers and one or more second semiconductor layers. In one embodiment, these layers may include semiconductor layers, sacrificial layers, or both. In another embodiment, these layers include alternating semiconductor layers and sacrificial layers. In some embodiments, operation 230 includes depositing on a substrate having a pre-cleaned surface (e.g., an oxide-free surface, which may be obtained after performing operation 210); a pre-treated surface (e.g., a hydrophobic surface or a passivated surface obtained after performing operation 220); and a pre-cleaned and pre-treated surface (e.g., a pristine surface, which may be obtained after performing operations 210 and 220).

[0183] Operation 230 may include any process that can be used to form at least the first semiconductor layer or the second semiconductor layer. Such a process may provide the first semiconductor layer, for example, by flowing a first precursor into a reaction chamber (e.g., an epitaxial chamber) and towards a substrate, and by generating high-energy species (e.g., a plasma including radicals, metastable species, and the like) that can react with the first precursor to deposit a semiconductor layer on the substrate. Examples of the first precursor include any of those described herein, such as those containing Group IV atoms (e.g., a C-containing precursor, an Si-containing precursor, a Ge-containing precursor, or an Sn-containing precursor, such as any of those described herein), Group III atoms (e.g., a B-containing precursor, an Al-containing precursor, a Ga-containing precursor, an In-containing precursor, or a Tl-containing precursor, such as any of those described herein), or Group V atoms (e.g., an N-containing precursor, a P-containing precursor, an As-containing precursor, an Sb-containing precursor, or a Bi-containing precursor, such as any of those described herein) and combinations thereof.

[0184] A further process may include providing the second semiconductor layer, for example, by flowing a second precursor into a reaction chamber (e.g., an epitaxial chamber) and towards the substrate, and by generating high-energy species (e.g., a plasma including radicals, metastable species, and the like) that can react with the second precursor to deposit a second layer on the first layer. Examples of the second precursor include any of those described herein, such as those containing Group IV atoms (e.g., a C-containing precursor, an Si-containing precursor, a Ge-containing precursor, or an Sn-containing precursor, such as any of those described herein), Group III atoms (e.g., a B-containing precursor, an Al-containing precursor, a Ga-containing precursor, an In-containing precursor, or a Tl-containing precursor, such as any of those described herein), or Group V atoms and combinations thereof, where the second precursor is different from the first precursor.

[0185] Any high-energy species may be employed during the deposition. As used herein, "high-energy species" may include any species that is reactive with one or more of the components provided during the deposition process. Such components may include precursors, deposited layers, and the like. Non-limiting examples of high-energy species include radicals, metastable species, ions, neutral species, plasmas, photons, radiation, excited molecules, excited atoms, reactive species, or other species described herein. In one non-limiting embodiment, the metastable species has an energy of about 0.01 - 1 eV. In another non-limiting embodiment, the ions have an energy of about 100 - 1000 eV. In yet another non-limiting embodiment, the high-energy species has an energy of about 0.01 - 1000 eV. In some non-limiting instances, any description herein regarding radicals and metastable species may encompass any high-energy species described herein.

[0186] The delivery of the first and second precursors may be repeated until a predetermined amount of the first and second layers has been deposited on the substrate. Non-limiting examples of the deposition process are described herein.

[0187] Optionally, to deposit the first or second semiconductor layer, two or more precursors may be delivered to the reaction chamber. For example, in the case of a silicon and germanium-containing layer (SiGe layer), a single precursor that provides both Si atoms and Ge atoms (e.g., germylsilane or H3Ge—SiH3) may be used. Alternatively, two precursors may be delivered to the substrate, where the first precursor may include Si atoms (e.g., as in silane, silane halide, or silicon halide precursors), and the second precursor may include Ge atoms (e.g., as in germane, germane halide, or germanium halide precursors). Additional precursors are described herein. Also as described herein, the precursors may be delivered in combination with one or more carrier gases, inert gases, and the like.

[0188] The method may include optional operations that may be performed before or after depositing the heterolayer. As Figure 2A shown, in one embodiment, the method includes an optional operation 225 of depositing a buffer layer on the surface of the substrate before depositing one or more epitaxial layers. In some embodiments, the buffer layer is deposited epitaxially. In other embodiments, the buffer layer is not deposited epitaxially. The buffer layer may be deposited in an epitaxial chamber or in another chamber different from the epitaxial chamber.

[0189] In another embodiment, the method includes an optional operation 235 of depositing a hard mask or a metal layer on the surface of the deposited epitaxial layer (e.g., epitaxial first semiconductor layer, epitaxial second semiconductor layer, or epitaxial sacrificial layer). In certain embodiments, operation 235 is not performed epitaxially.

[0190] Once the desired number of heterolayers have been deposited, the stack may be removed from the reaction chamber. As Figure 2A further shown, method 200A may further include an operation 240 of performing a reactor clean. Operation 240 may be performed at any time after operation 230 or before operation 230. In this way, the reaction chamber may be cleaned before depositing the first and second semiconductor layers. In one embodiment, operation 240 includes removing contaminants from the environment or surface within the reaction chamber. In one example, performing a reactor clean includes delivering a halogen-containing vapor, a halogen-containing plasma, a fluorine-containing vapor, a fluorine-containing plasma, a chlorine-containing vapor, or a chlorine-containing plasma to the reaction chamber. Non-limiting examples of reactor clean processes are described herein.

[0191] Further operations may be performed to ensure an effective environment for epitaxial deposition. In one example, after performing operation 240 of cleaning the reactor, an optional operation 250 of performing reactor conditioning may be performed. In some embodiments, operation 250 includes passivating the environment or surface within the reaction chamber. In one example, passivation may include absorbing or trapping halogen atoms or may be performed in any operation herein (e.g., Figure 2AOther contaminants introduced during the pre-cleaning operation 210 / 210B / 210D / 210F / 210G, pre-treatment operation 220 / 220D / 220E / 220F / 220G, deposition operation 230, or reactor cleaning operation 240 in -G. Non-limiting examples of reactor processing techniques are described herein.

[0192] Any combination of optional operations may be performed. As Figure 2B shown, method 200B may further require an operation 210B to pre-clean the substrate surface, thus providing a pre-cleaned surface. In one non-limiting example, operation 210B includes removing oxides from the surface of the substrate. Such a pre-cleaning operation 210B may be performed with or without operation 205 (for in-situ cleaning of the substrate). For example, if the pre-cleaning operation 210B achieves the same purpose as the in-situ operation 205, the in-situ operation 205 may not be performed. In another example, if the pre-cleaning operation 210B provides the same surface as when the in-situ operation 205 is performed, the in-situ operation 205 may not be performed.

[0193] As Figure 2C shown, method 200C may further require an operation 205C to perform in-situ cleaning on the substrate surface, thus removing various contaminants from the substrate surface. Such an in-situ cleaning operation 205C may be performed with or without operation 210 (for in-situ pre-cleaning of the substrate). For example, if the in-situ cleaning operation 205C achieves the same purpose as the in-situ operation 210, the in-situ operation 210 may not be performed. In another example, if the in-situ cleaning operation 205C provides the same surface as when the in-situ operation 210 is performed, the in-situ operation 210 may not be performed.

[0194] After in-situ cleaning or in-situ pre-cleaning, a pre-treatment operation may be performed. As Figure 2D seen, method 200D may further require an operation 210D to pre-clean the substrate surface, thus providing a pre-cleaned surface (e.g., thus removing oxides from the substrate surface to provide an oxide-free surface); followed by an operation 220D to pre-treat the substrate surface, thus providing a pre-treated surface (e.g., a hydrophobic surface or a passivated surface).

[0195] As Figure 2E shown, method 200E may further require an operation 205E to perform in-situ cleaning on the substrate surface, thus removing contaminants from the substrate surface; followed by an operation 220E to pre-treat the substrate surface, thus providing a pre-treated surface (e.g., a hydrophobic surface or a passivated surface).

[0196] In still other examples, both in-situ cleaning and in-situ pre-cleaning are performed. As Figure 2FAs shown, method 200F may further require an operation 205F to clean the substrate surface ex-situ, thereby removing contaminants from the substrate surface; followed by an operation 210F to pre-clean the substrate surface, thereby providing a pre-cleaned substrate surface; and then followed by an operation 220F to pre-treat the substrate surface, thereby providing a pre-treated substrate surface.

[0197] After performing various cleaning, pre-cleaning, and pre-treatment operations on the substrate, the process may include an operation to clean and process the reactor. As Figure 2G shown, method 200G may include an operation 205G to clean the substrate surface ex-situ, thereby removing contaminants from the substrate surface; followed by an operation 210G to pre-clean the substrate surface, thereby providing a pre-cleaned surface; and then followed by an operation 220G to pre-treat the substrate surface, thereby providing a pre-treated surface. The deposition operation 230 may be performed together with an optional operation 225 to provide a buffer layer (before operation 230) and an optional operation 235 to deposit a hard mask (after operation 230). In a particular embodiment, the hard mask is not an epitaxial layer, or operation 235 is not performed epitaxially.

[0198] Further operations may be performed to process the reactor chamber after deposition or to ensure an effective environment for subsequent epitaxial deposition. In one example, as Figure 2G shown, method 200G may further include an operation 240 to clean the reactor chamber, thereby removing contaminants from any environment within the chamber; followed by an operation 250G to perform reactor treatment, thereby passivating the environment within the reactor chamber. In one example, passivation may include absorbing or trapping halogen atoms or other contaminants that may be introduced during any operation herein (e.g., Figure 2A -G's pre-cleaning operations 210 / 210B / 210D / 210F / 210G, pre-treatment operations 220 / 220D / 220E / 220F / 220G, deposition operation 230, or reactor cleaning operation 240). Non-limiting examples of reactor treatment processes are described herein.

[0199] Figure 2H A non-limiting schematic diagram of system 250 is provided, which may be configured to perform any method or operation described herein. As shown, the non-limiting high-vacuum platform 260 may be configured to optionally include a pre-cleaning chamber 270 and include an epitaxial chamber 280. The ex-situ cleaning operation 251 may be performed outside the platform to clean the substrate. Such a substrate may be transferred to the pre-cleaning chamber 270 (if present), or directly transferred to the epitaxial chamber 280.

[0200] As shown in the figure, the pre-cleaning chamber 270 can be configured to perform a pre-cleaning operation, for example, by coupling one or more inlets (e.g., process gas inlet 262 if the reagent is in vapor form) to a reagent 252 for performing the pre-cleaning operation. Non-limiting reagents for pre-cleaning a substrate can include, for example, one or more fluorine-containing reactants or other reagents described herein. As used herein, the terms "reactant" and "reagent" can be used interchangeably. After pre-cleaning, the substrate can then be transferred to the epitaxial chamber 280. To maintain the substrate surface, such transfer can be performed under vacuum.

[0201] In the epitaxial chamber, a pre-treatment operation can be performed to provide a passivated surface to the substrate. For example, the epitaxial chamber 280 can be configured to have one or more inlets (e.g., process gas inlet 263, which is in turn fluidly coupled to gas inlet 269) coupled to a reagent 253 for performing the pre-treatment operation. Non-limiting reagents for pre-treating a substrate can include, for example, hydrogen, hydrogen-containing plasma, or other reagents described herein.

[0202] After pre-treatment, the substrate remains in the epitaxial chamber 280. One or more precursors can be delivered to the substrate in the presence of a plasma, which in turn can provide radicals or metastable species that react with the precursors to deposit a semiconductor layer or a sacrificial layer on the substrate. For example, the epitaxial chamber 280 can be configured to have one or more inlets (e.g., process gas inlet 264, which is in turn fluidly coupled to gas inlet 269) coupled to a reagent 254 for performing the deposition operation. Non-limiting reagents for deposition can include, for example, any precursor (e.g., Si-containing, Ge-containing, or Si- and Ge-containing precursors) or other reagents described herein.

[0203] The buffer layer can be deposited in the epitaxial chamber 280 or in another chamber different from the epitaxial chamber. For example, the buffer layer can be deposited in another chamber disposed within the high-vacuum platform 260 or in another chamber located outside the platform.

[0204] To provide a plasma, the epitaxial chamber 280 or one or more inlets coupled to the epitaxial chamber 280 can in turn be coupled to a plasma source (e.g., a remote plasma source). As used herein, a "remote plasma source" refers to plasma generation that occurs away from the substrate, as further described herein. In some non-limiting examples, the remote plasma source is located outside the epitaxial chamber 280 but is fluidly connected to the epitaxial chamber (e.g., through one or more gas inlets). In other non-limiting instances, the remote plasma source is located upstream of the epitaxial chamber where the substrate is located. As used herein, the terms "upstream" and "downstream" relate to relative position terms, where upstream refers to a position before a given point and downstream refers to a position after a given point.

[0205] After deposition, the substrate and the resulting film can be removed from the epitaxial chamber 280. Further operations can include cleaning and treating the epitaxial chamber. As Figure 2H shown, the epitaxial chamber 280 can be configured to have one or more inlets (e.g., process gas inlets 265, 266, which are in turn fluidly coupled to the gas inlet 269) coupled to a reagent 255 for performing reactor cleaning operations or coupled to a reagent 256 for performing reactor treating operations. Non-limiting reagents for cleaning and treating the reactor can include, for example, hydrogen gas, hydrogen-containing plasma, halogen-containing gas, halogen-containing plasma, silane gas, germane gas, or other reagents described herein. Any inlet herein (e.g., gas inlets 262 - 266, 269) can be directly or indirectly connected to a chamber (e.g., chambers 270, 280), and such inlets can include one or more valves (e.g., valve 268) to control the introduction of process gases (e.g., reagents 252 - 256) into the chamber (e.g., chambers 270, 280).

[0206] In certain embodiments, the pre-cleaning operation and the pre-treatment operation of the substrate are performed in separate chambers. Figure 2I A non-limiting schematic of the system 290 is provided. As shown, the non-limiting high-vacuum platform 265 can be configured to optionally include a pre-cleaning chamber 270, optionally include a pre-treatment chamber 275, and include an epitaxial chamber 280.

[0207] As shown, the pre-cleaning chamber 270 can be configured to perform a pre-cleaning operation, for example, by coupling one or more inlets (e.g., process gas inlet 262 if the reagent is in vapor form) to a reagent 252 for performing the pre-cleaning operation. After pre-cleaning, the substrate can then be transferred to the pre-treatment chamber 275, which can be configured to have one or more inlets (e.g., process gas inlet 263) coupled to a reagent 253 for performing the pre-treatment operation. To maintain the substrate surface, such transfer from the pre-cleaning chamber 270 to the pre-treatment chamber 275 can be performed under vacuum.

[0208] Next, the pre-cleaned and pre-treated substrate can be transferred from the pre-treatment chamber 275 to the epitaxial chamber 280, which can be performed under vacuum. The epitaxial chamber 280 can be configured to have one or more inlets (e.g., process gas inlets 264, 265, 266, which are in turn fluidly coupled to the gas inlet 269) coupled to the reagent 254 for performing deposition operations or coupled to the reagent 255 for performing reactor cleaning operations or coupled to the reagent 256 for performing reactor treatment operations. With an integrated platform, the transfer between chambers can be performed under vacuum. Any inlet herein (e.g., gas inlets 262 - 266, 269) can be directly or indirectly connected to a chamber (e.g., chambers 270, 275, 280), and such inlets can include one or more valves (e.g., valve 268) to control the introduction of process gases (e.g., reagents 252 - 256) into the chamber (e.g., chambers 270, 275, 280).

[0209] Figure 3A A non-limiting schematic diagram for providing a stack is provided. In one embodiment, method 300 includes a plurality of operations. In operation 301, a substrate is provided in a processing chamber such as a reactor. In some implementations, the reactor can be a reactor configured to perform plasma-based deposition operations. In operation 302, the substrate is exposed to a first precursor. It should be noted that during the time the substrate is exposed to the first precursor, the substrate can be additionally exposed to radicals or metastable species (e.g., any of those described herein) or other reaction-promoting stimuli that interact with the precursor to deposit a layer (e.g., a semiconductor layer or a sacrificial layer) on the substrate. As used herein, "reaction-promoting stimulus" is any type of chemical, energy, or other stimulus that can interact with a precursor to deposit material on a surface. In some implementations, a plasma (e.g., a remote plasma or an in-situ plasma in the processing chamber), a hot filament, or other sources (e.g., any of those described herein) can be used to generate radicals, metastable species, and the like. In some embodiments, the precursor can flow to the substrate without being activated in a remote plasma source.

[0210] As a result of operation 302, a first semiconductor layer (e.g., an epitaxial semiconductor layer) is deposited on the substrate. Optionally, in operation 302a, the processing chamber is purged. In operation 303, the substrate is exposed to a second precursor and a third precursor. Generally, the second precursor in operation 303 is different from the first precursor employed in operation 302, thus providing a different layer (or heterolayer) with a different composition. However, the third precursor used in operation 303 can be the same as or different from the first precursor used in operation 302.

[0211] Similar to what was described above regarding operation 302, during the time the substrate is exposed to the second precursor and the third precursor in operation 303, the substrate may be additionally exposed to free radicals, metastable species, and the like (e.g., hydrogen-containing free radicals such as hydrogen radicals (H*); nitrogen-containing free radicals such as nitrogen radicals (N*); argon metastable species such as argon metastable species (Ar*); helium metastable species such as helium metastable species (He*) or the like), which interact with the precursors to deposit a second semiconductor layer on the substrate. In some embodiments, the free radicals, metastable species, and the like may be selected such that they do not interact with silicon. For example, in one embodiment, the reactive plasma may substantially not contain components that react with silicon. In one example, the reactive plasma may contain only hydrogen (e.g., H* or H2), deuterium (e.g., D* or D2), deuterated hydrogen (HD), inert gases (e.g., He, Ar, He*, Ar*, etc.), or any combination thereof. In another example, the reactive plasma does not contain nitrogen-containing species, halogen-containing species, or oxygen-containing species. The free radicals or metastable species may be generated using a plasma (e.g., remote plasma or in-situ plasma) or any other suitable technique (e.g., a hot filament as described above). In some embodiments, the second precursor and the third precursor flow to the substrate without being activated in a remote plasma source. The result of operation 303 is that a second semiconductor layer (e.g., an epitaxial semiconductor layer) is deposited on the substrate. Optionally, in operation 303a, the chamber is purged. In some embodiments, as a supplement or alternative to purging the chamber, a plasma may be generated, for example, from hydrogen. This can eliminate sources of other elements (e.g., Ge) remaining in the chamber such that another layer (e.g., a Si-containing layer) is not contaminated by the residual elements. In some implementations, this can create a clear interface between the layers.

[0212] In operation 305, it is determined whether a film of sufficient thickness has been deposited. This determination may be made based on whether the total thickness of the layer exceeds a predetermined threshold, whether more than a predetermined amount of alternating first and second semiconductor layers has been deposited, or any suitable combination thereof. If it is determined in operation 305 that the film has not been deposited to a sufficient thickness (''no'' at 305), the process may loop back to operation 302 and the substrate is exposed to the first precursor. In some implementations, blocks 302 - 305 are repeated n times. Conversely, if it is determined in operation 305 that the film has been deposited to a sufficient thickness (''yes'' at 305), the process ends.

[0213] In certain embodiments, the method may provide for rapid switching between operations. For example, the apparatus or system implementing the method may be configured to rapidly switch between various operations during deposition. Employing Figure 3AThe non-limiting method 300 therein can provide rapid switching between stages or operations within a deposition cycle, such as rapid switching between an exposure operation 302, a purge operation 302a, a further exposure operation 303, and a further purge operation 303a, and subsequent repeated cycles n times. The rapid switching can occur between any of the operations described herein, such as Figure 3B between various operations 320 / 325 / 330 / 335 in Figure 3C between various operations as described by stages 370A / 375A / 380A / 385A in the first deposition cycle 361A and stages 370B / 375B / 380B / 385B in the second deposition cycle in Figure 3D between various operations as described by stages 371A / 395A / 381A / 396A in the first deposition cycle 391A and stages 371B / 395B / 381B / 396B in the second deposition cycle 391B in Figure 3E between various operations 3020 / 3022 / 3024 / 3030 / 3032 / 3034 in Figure 4A between various operations 402 / 402a / 403 / 403a in Figure 4B between various operations 420 / 425 / 430 / 435 in, and such as Figure 4C between various operations as described by stages 470A / 475A / 480A / 485A in the first deposition cycle 461A and stages 470B / 475B / 480B / 485B in the second deposition cycle 461B in. Methods, systems, and apparatuses (e.g., as in paragraphs

[0524] -

[0525] herein) can be implemented as described herein to facilitate rapid switching.

[0214] This process can be implemented using specific precursors. In Figure 3BIn the example shown, a silicon-containing precursor is used to deposit a Si layer, and a silicon-containing precursor and a germanium-containing precursor are used to deposit a SiGe layer. At 310, a substrate is provided in a processing chamber of a reactor, for example. In some implementations, the reactor can be a reactor configured to perform plasma-based deposition operations. At 320, the substrate is exposed to the silicon-containing precursor. It should be noted that during the time the substrate is exposed to the silicon-containing precursor, the substrate can be additionally exposed to radicals (e.g., hydrogen-containing radicals, nitrogen-containing radicals, or the like), metastable species (e.g., argon-containing metastable species, helium-containing metastable species, or the like), or other reaction-promoting stimuli that interact with the precursor to deposit a Si layer on the substrate. It should be noted that in some embodiments, the reactive plasma can substantially not contain components that react with silicon. In one example, the reactive plasma can contain only hydrogen (e.g., H* or H2), deuterium (e.g., D* or D2), deuterated hydrogen (HD), an inert gas (e.g., He, Ar, He*, Ar*, etc.), or any combination thereof. In another example, the reactive plasma does not contain nitrogen-containing species, halogen-containing species, or oxygen-containing species. In some implementations, the radicals, metastable species, etc. can be generated using a plasma, which can be a remote plasma (e.g., upstream of the processing chamber where the substrate is located) or generated in situ in the processing chamber where the substrate is located. In other implementations, the radicals, metastable species, and the like can be generated using other techniques. For example, in some implementations, the radicals, metastable species, and the like can be generated using a hot filament (e.g., a tungsten filament), where the high temperature of the filament is used to generate radicals, metastable species, and the like from a gas (e.g., a hydrogen-containing gas) flowing around the filament. In some embodiments, the silicon-containing precursor can flow to the substrate without being activated in a remote plasma source. As a result of 303, a Si layer (e.g., an epitaxial Si layer) is deposited on the substrate. Optionally, at 325, the chamber is purged. In some embodiments, as a supplement or alternative to purging the chamber, a plasma can be generated from, for example, hydrogen. This can eliminate sources of other elements (e.g., Ge) remaining in the chamber so that another layer (e.g., a Si-containing layer) is not contaminated by the residual elements. In some implementations, this can form a clear interface between the layers.

[0215] At 330, the substrate is exposed to a silicon precursor and a germanium precursor. The silicon precursor used at 330 may be the same as or different from the silicon precursor used at 320. Similar to what was described above regarding block 320, during the time the substrate is exposed to the silicon precursor and the germanium precursor, the substrate may additionally be exposed to free radicals (e.g., hydrogen-containing free radicals, nitrogen-containing free radicals, or the like) or metastable species (e.g., argon-containing metastable species, helium-containing metastable species, or the like), which interact with the precursors to deposit a SiGe layer on the substrate. It should be noted that in some embodiments, the reactive plasma may substantially not contain components that react with silicon or with germanium or with both silicon and germanium. In one example, the reactive plasma may contain only hydrogen (e.g., H* or H2), deuterium (e.g., D* or D2), deuterated hydrogen (HD), an inert gas (e.g., He, Ar, He*, Ar*, etc.), or any combination thereof. In another example, the reactive plasma does not contain nitrogen-containing species, halogen-containing species, or oxygen-containing species. The free radicals or metastable species can be generated using a plasma (e.g., a remote plasma or an in-situ plasma) or any other suitable technique (e.g., a hot filament as described above). In some embodiments, the silicon precursor and the germanium precursor flow to the substrate without being activated in a remote plasma source. As a result of 330, a SiGe layer (e.g., an epitaxial SiGe layer) is deposited on the substrate. Optionally, at 335, the chamber is purged. In some embodiments, as a supplement or alternative to purging the chamber, a plasma may be generated, for example, from hydrogen. This can form a clear interface between the layers.

[0216] At 340, it is determined whether a film of sufficient thickness has been deposited. This determination can be made based on whether the total thickness of the layer exceeds a predetermined threshold, whether more than a predetermined amount of alternating Si and SiGe layers have been deposited, or any suitable combination thereof. If at 340 it is determined that the film has not been deposited to a sufficient thickness ("no" at 340), then the process can loop back to operation 320 and the substrate is exposed to the silicon precursor. In some implementations, blocks 320 - 340 are repeated n times. Conversely, if at 340 it is determined that the film has been deposited to a sufficient thickness ("yes" at 340), then the process ends.

[0217] Figure 3CProvide a non - limiting process timing diagram 360 for depositing alternating Si and SiGe layers using plasma. During the first deposition cycle 361A, the Si exposure stage 370A includes exposing the substrate to a silicon - containing precursor. The silicon - containing precursor can be provided in combination with a carrier gas. During the Si exposure stage 370A, a plasma is ignited using a source gas. During the Si exposure stage 370A, a Si layer is deposited on the substrate. During the purge stage 375A, the flow of the silicon - containing precursor to the processing chamber is stopped. Additionally, the plasma is turned off, and the flow of the source gas used to generate the plasma is also stopped. The carrier gas can continue to flow to the processing chamber. During the SiGe exposure stage 380A, the substrate is exposed to a silicon - containing precursor and a germanium - containing precursor. During the SiGe exposure stage 380A, a plasma is ignited using a source gas. During the SiGe exposure stage 380A, a SiGe layer is deposited, for example, on the Si layer.

[0218] The first deposition cycle 361A ends at the plasma turn - on of the purge stage 385A. It should be noted that in some implementations, there may be no interruption between steps. In some such implementations, the silicon - containing precursor and the germanium - containing precursor can flow into the chamber (e.g., “turned on”) or be transferred (e.g., “turned off”). Then, a second deposition cycle 361B is performed, which includes a second Si exposure stage 370B, a subsequent purge stage 375B, a second SiGe exposure stage 380B, and a subsequent purge stage 385B. After the second deposition cycle 361B, two sets of alternating Si and SiGe layers have been deposited.

[0219] Figure 3D Provide a non - limiting process timing diagram 390 for depositing alternating Si and SiGe layers using plasma. Here, instead of purging the chamber, a plasma is generated to eliminate sources of other non - Si elements (e.g., Ge) remaining in the chamber to ensure that the Si layer is not contaminated by the remaining elements. For example, during the first deposition cycle 391A, the Si exposure stage 371A includes exposing the substrate to a silicon - containing precursor. The silicon - containing precursor can be provided in combination with a carrier gas. During the Si exposure stage 371A, a plasma is ignited using a first source gas (source gas 1). During the Si exposure stage 371A, a Si layer is deposited on the substrate. During the purge stage 395A, the flow of the silicon - containing precursor to the processing chamber is stopped. Additionally, the plasma is turned off, and the flow of the first source gas used to generate the plasma is also stopped. The carrier gas can optionally continue to flow to the processing chamber.

[0220] During the SiGe exposure stage 381A, the substrate is exposed to a silicon precursor and a germanium precursor. During the SiGe exposure stage 381A, a plasma is ignited using a first source gas, and then, for example, a SiGe layer is deposited on the Si layer. It should be noted that in some implementations, there may be no interruption between steps. In some such implementations, the silicon precursor and the germanium precursor may flow into the chamber (e.g., "turned on") or be transferred (e.g., "turned off").

[0221] The first deposition cycle 391A ends with a removal stage 396A that uses a plasma (instead of or in addition to a purge stage) to remove any source of a second element (e.g., Ge) remaining in the chamber. For example, the removal stage 396A can be configured to eliminate any Ge source in the chamber so that it does not contaminate the pure Si layer. During the removal stage 396A, the plasma is turned on and the flow of a second source gas (source gas 2) is initiated to generate the plasma. Of course, if the first and second source gases are the same (e.g., source gas 1 = source gas 2 = H2), then only one source gas may be used throughout the first deposition cycle 391A.

[0222] Then a second deposition cycle 391B is performed, which includes a second Si exposure stage 371B, a second purge stage 395B, a second SiGe exposure stage 381B, and a second removal stage 396B. After the second deposition cycle 391B, two sets of alternating Si and SiGe layers have been deposited.

[0223] Other operations may be performed between or within the deposition cycles. In one example, the substrate may be exposed to a plasma (e.g., any of those described herein), thereby providing a preparatory surface between the first and second semiconductor layers.

[0224] Such a preparatory surface may be provided during deposition. In Figure 3EIn the example shown, a first semiconductor layer is deposited using a first precursor, and a second semiconductor layer is deposited using a second precursor and an optional third precursor. At 3010, a substrate is provided in a processing chamber, such as a reactor. In some implementations, the reactor may be configured to perform a plasma-based deposition operation. At 3020, the substrate is exposed to the first precursor. It should be noted that during the time the substrate is exposed to the first precursor, the substrate may additionally be exposed to radicals (e.g., hydrogen-containing radicals, nitrogen-containing radicals, or the like), metastable species (e.g., argon-containing metastable species, helium-containing metastable species, or the like), or other reaction-promoting stimuli that interact with the precursor to deposit the first semiconductor layer on the substrate. It should be noted that in some embodiments, the reactive plasma may substantially not contain components that react with silicon or with germanium or with both silicon and germanium. In one example, the reactive plasma may contain only hydrogen (e.g., H* or H2), deuterium (e.g., D* or D2), deuterated hydrogen (HD), an inert gas (e.g., He, Ar, He*, Ar*, etc.), or any combination thereof. In another example, the reactive plasma does not contain nitrogen-containing species, halogen-containing species, or oxygen-containing species. In some implementations, the radicals, metastable species, and the like may be generated using a plasma, which may be a remote plasma (e.g., upstream of the processing chamber where the substrate is located) or generated in-situ in the processing chamber where the substrate is located. In other implementations, the radicals, metastable species, and the like may be generated using other techniques (e.g., any of those described herein, such as a hot filament). In some embodiments, the first precursor may flow to the substrate without being activated in a remote plasma source. The result of 3020 is that a first semiconductor layer (e.g., an epitaxial semiconductor layer) is deposited on the substrate.

[0225] Optionally, at 3022, the chamber is purged. In some embodiments, as a supplement or alternative to purging the chamber, a plasma may be generated, as shown in optional operation 3024. Purging or generating a plasma may remove sources of other elements (e.g., Ge) remaining in the chamber such that the next layer to be deposited (e.g., the second semiconductor layer) is not contaminated by the remaining elements. In some implementations, this may form a clear interface between the first semiconductor layer and the second semiconductor layer.

[0226] In optional operation 3024, a plasma is generated to provide a preparatory surface for the deposited first semiconductor layer. In one embodiment, the plasma may be generated by, for example, hydrogen, argon, helium, or other radicals, metastable species, or ions described herein. In some implementations, this may provide a smoothed surface for depositing the next layer (e.g., depositing the second semiconductor layer).

[0227] At 3030, the substrate is exposed to a second precursor and an optional third precursor. The second precursor used at 3030 may be the same as or different from the first precursor used at 3020. Similar to what was described above regarding block 3020, during the time the substrate is exposed to the second precursor and the optional third precursor, the substrate may additionally be exposed to free radicals (e.g., hydrogen-containing free radicals, nitrogen-containing free radicals, or the like) or metastable species (e.g., argon-containing metastable species, helium-containing metastable species, or the like), which interact with the precursors to deposit a second semiconductor layer on the substrate. In some embodiments, the free radicals, metastable species, and the like may be selected to be those that do not interact with the atoms deposited in the first or second semiconductor layer. For example, in some embodiments, the reactive plasma may substantially not contain components that react with silicon or with germanium or with both silicon and germanium. In one example, the reactive plasma may contain only hydrogen (e.g., H* or H2), deuterium (e.g., D* or D2), deuterated hydrogen (HD), inert gases (e.g., He, Ar, He*, Ar*, etc.), or any combination thereof. In another example, the reactive plasma does not contain nitrogen-containing species, halogen-containing species, or oxygen-containing species. The free radicals, metastable species, and the like may be generated using a plasma (e.g., a remote plasma or an in-situ plasma) or any other suitable technique (e.g., a hot filament as described above). In some embodiments, the second precursor and the optional third precursor flow to the substrate without being activated in a remote plasma source. As a result of 3030, a second semiconductor layer (e.g., an epitaxial semiconductor layer) is deposited on the substrate.

[0228] Optionally, at 3032, the chamber is purged. In some embodiments, as a supplement to or an alternative to purging the chamber, a plasma may be generated, for example, from hydrogen. This may eliminate sources of other elements (e.g., Ge) remaining in the chamber such that the next layer to be deposited (e.g., another first semiconductor layer) is not contaminated by the remaining elements. In some implementations, this may create a clean interface between the first and second semiconductor layers.

[0229] Optionally, at 3034, a plasma is generated to provide a preparatory surface for the deposited second semiconductor layer. In one embodiment, the plasma may be generated from, for example, hydrogen, argon, helium, or other free radicals, metastable species, or ions described herein. In some implementations, this may provide a smoothed surface for depositing the next layer (e.g., depositing another first semiconductor layer).

[0230] At 3050, it is determined whether a film of sufficient thickness has been deposited. This determination can be made based on whether the total thickness of the layer exceeds a predetermined threshold, whether more than a predetermined amount of alternating first and second semiconductor layers have been deposited, or any suitable combination thereof. If at 3050 it is determined that the film has not been deposited to a sufficient thickness ("No" at 3050), the process can loop back to operation 3020 and expose the substrate to the first precursor. In some implementations, blocks 3020 - 3050 are repeated n times. Conversely, if at 3050 it is determined that the film has been deposited to a sufficient thickness ("Yes" at 3050), the process ends.

[0231] Figure 4A-4C A non - limiting method is provided for depositing a first semiconductor layer using a single precursor and a second semiconductor layer using a single different precursor. In Figure 4A the example shown, method 400 includes using a first precursor to deposit a first semiconductor layer and a second precursor to deposit a second semiconductor layer. At 401, a substrate is provided in a processing chamber, such as a reactor (e.g., which is optionally configured to perform plasma - based deposition operations). At 402, the substrate is exposed to the first precursor. It should be noted that during the time the substrate is exposed to the first precursor, the substrate can additionally be exposed to high - energy species (e.g., radicals, metastable species, and the like), which interact with the precursor to deposit a semiconductor layer on the substrate. In some implementations, the high - energy species (e.g., radicals, metastable species, and the like) can be generated using a plasma or using other techniques (e.g., any of those described herein). The result of 402 is that a first semiconductor layer (e.g., an epitaxial semiconductor layer) is deposited on the substrate. Optionally, at 402a, the processing chamber is purged.

[0232] At 403, the substrate is exposed to a second precursor different from the first precursor. Similar to what was described above for operation 402, during the time the substrate is exposed to the second precursor, the substrate can additionally be exposed to radicals, metastable species, and the like, which interact with the precursor to deposit a second semiconductor layer on the substrate (e.g., and on the top surface of the first semiconductor substrate). The radicals, metastable species, and the like can be generated using a plasma (e.g., a remote plasma or an in - situ plasma) or any other suitable technique (e.g., a hot filament, as described above). The result of 403 is that a second semiconductor layer (e.g., an epitaxial second layer) is deposited on the substrate. Optionally, at 403a, the chamber is purged.

[0233] At 404, it is determined whether a film of sufficient thickness has been deposited. This determination can be made based on whether the total thickness of the layer exceeds a predetermined threshold, whether more than a predetermined amount of alternating first and second semiconductor layers have been deposited, or any suitable combination thereof. If at 404 it is determined that the film has not been deposited to a sufficient thickness ("No" at 404), the process can loop back to 402 and the substrate is exposed to the first precursor. In some implementations, blocks 402 - 404 are repeated n times. Conversely, if at 404 it is determined that the film has been deposited to a sufficient thickness ("Yes" at 404), the process ends.

[0234] Figure 4B A non - limiting schematic illustration for providing a stack having alternating Si and SiGe layers is provided. In Figure 4B the example shown, a SiGe layer is deposited using a single precursor (Si - and - Ge - containing precursor) that includes both silicon atoms and germanium atoms, which is different from that described using two different precursors (Si - containing precursor and Ge - containing precursor) as Figure 3B shown and described above in connection with Figure 3B In 410, a substrate is provided in a processing chamber such as a reactor. In some implementations, the reactor can be a reactor configured to perform plasma - based deposition operations.

[0235] In 420, the substrate is exposed to a Si - containing precursor. It should be noted that during the time the substrate is exposed to the Si - containing precursor, the substrate can additionally be exposed to energetic species (e.g., any of those described herein), radicals (e.g., hydrogen - containing radicals, nitrogen - containing radicals, or the like), or metastable species (e.g., argon - containing metastable species, helium - containing metastable species, or the like), which interact with the precursor to deposit a Si layer on the substrate. In some implementations, the energetic species, radicals, metastable species, or the like can be generated using a plasma, which can be a remote plasma (e.g., upstream of the processing chamber where the substrate is located) or generated in - situ in the processing chamber where the substrate is located. It should be noted that in some embodiments, the reactive plasma can substantially not contain components that react with silicon or with germanium or with both silicon and germanium. In one example, the reactive plasma can contain only hydrogen (e.g., H* or H2), deuterium (e.g., D* or D2), deuterated hydrogen (HD), inert gases (e.g., He, Ar, He*, Ar*, etc.), or any combination thereof. In another example, the reactive plasma does not contain nitrogen - containing species, halogen - containing species, or oxygen - containing species. In other implementations, the energetic species, radicals, metastable species, or the like can be generated using other techniques. For example, in some implementations, the energetic species, radicals, metastable species, or the like can be generated using a hot filament (e.g., a tungsten filament), where the high temperature of the filament is used to generate energetic species, radicals, metastable species, and the like from a gas (e.g., hydrogen - containing gas) flowing around the filament. The result of 420 is that a Si layer (e.g., an epitaxial Si layer) is deposited on the substrate.

[0236] Optionally, at 425, clean the processing chamber.

[0237] At 430, expose the substrate to silicon- and germanium-containing precursors. Similar to what was described above regarding block 420, during the time the substrate is exposed to the silicon- and germanium-containing precursors, the substrate can additionally be exposed to free radicals (e.g., hydrogen-containing free radicals, nitrogen-containing free radicals, or the like) or metastable species (e.g., argon-containing metastable species, helium-containing metastable species, or the like), which interact with the precursors to deposit a SiGe layer on the substrate. Free radicals, metastable species, and the like can be generated using a plasma (e.g., remote plasma or in-situ plasma) or any other suitable technique (e.g., a hot filament as described above). It should be noted that in some embodiments, the reactive plasma can substantially not contain components that react with silicon or with germanium or with both silicon and germanium. In one example, the reactive plasma can contain only hydrogen (e.g., H* or H2), deuterium (e.g., D* or D2), deuterated hydrogen (HD), inert gases (e.g., He, Ar, He*, Ar*, etc.), or any combination thereof. In another example, the reactive plasma does not contain nitrogen-containing species, halogen-containing species, or oxygen-containing species. As a result of 430, a SiGe layer (e.g., an epitaxial SiGe layer) is deposited on the substrate.

[0238] Optionally, at 435, clean the chamber.

[0239] At 440, determine whether a film of sufficient thickness has been deposited. This determination can be made based on whether the total thickness of the layer exceeds a predetermined threshold, whether more than a predetermined amount of alternating Si and SiGe layers have been deposited, or any suitable combination thereof. If at 440 it is determined that the film has not been deposited to a sufficient thickness (''No'' at 440), the process can loop back to 420 and expose the substrate to the silicon-containing precursor. In some implementations, blocks 420 - 440 are repeated n times. Conversely, if at 440 it is determined that the film has been deposited to a sufficient thickness (''Yes'' at 440), the process ends.

[0240] Figure 4C Provide corresponding to Figure 4BNon-limiting process timing diagram 460 of the method shown in FIG. During the first deposition cycle 461A, the Si exposure stage 470A includes exposing the substrate to a silicon-containing precursor. The silicon-containing precursor can be provided in combination with a carrier gas. During the Si exposure stage 470A, the plasma is turned on using a source gas. During the Si exposure stage 470A, a Si layer is deposited on the substrate. During the purge stage 475A, the flow of the silicon-containing precursor to the processing chamber is stopped. Additionally, the plasma is turned off, and the flow of the source gas used to generate the plasma is also stopped. The carrier gas can continue to flow to the processing chamber. During the SiGe exposure stage 480A, the substrate is exposed to a silicon- and germanium-containing precursor. During the SiGe exposure stage 480A, the plasma is turned on using a source gas. During the SiGe exposure stage 480A, a SiGe layer is deposited, for example, on the Si layer. The first deposition cycle 461A ends at the purge stage 485A. Then, a second deposition cycle 461B is carried out, which includes a second Si exposure stage 470B, a subsequent purge stage 475B, a second SiGe exposure stage 480B, and a subsequent purge stage 485B. After the second deposition cycle 461B, two sets of alternating Si and SiGe layers have been deposited. Growth of the epitaxial layer

[0241] The structures herein (e.g., films, stacks, and the like) can include one or more layers, which can have any useful properties. For example, the vertical stacks herein can include at least one Si layer and at least one SiGe layer. Each layer can be characterized by having one or more different structural features.

[0242] In some non-limiting embodiments, the layer is characterized as an epitaxial layer. As used herein, the terms "single crystal", "crystalline", and "epitaxial" are used to describe a predominantly large crystal structure, which may have a tolerable amount of defects. The crystallinity of a layer generally ranges along a continuum from amorphous to polycrystalline to single crystal, so the crystal structure is generally still considered single crystal or epitaxial despite having a low density of defects. The term "epitaxial" refers to a type of growth or deposition in which the newly deposited overlying crystalline layer is formed with one or more well-defined orientations compared to the underlying crystalline substrate or underlying crystalline layer. "Homogeneous epitaxy" refers to epitaxy in which the overlying layer has the same material as the underlying layer. "Homogeneous epitaxial layer" refers to a layer formed by homogeneous epitaxy as described herein. "Heteroepitaxy" refers to epitaxy in which the overlying layer has a different material from the underlying layer. "Heteroepitaxial layer" refers to a layer formed by heteroepitaxy as described herein.

[0243] A further feature of the epitaxial layer may be that it is strained. Generally, different materials will have different lattice constants. Typically, at the interface between materials with different lattice parameters, misfit dislocations (or defects) can be observed. However, under certain conditions, elastic strain can accommodate any misfit dislocations that may exist at the interface between the underlying layer and the overlying layer. For example, under pseudomorphic (or non - typical form) growth conditions, the newly deposited overlying layer can adopt the lateral lattice constant of the underlying layer, rather than the inherent lattice constant of the bulk film formed by the material.

[0244] Thus, in one non - limiting example, the layer feature may be that it is a strained layer, where the lattice structure within the strained layer is different from the inherent lattice constant of the material. Such lattice strain can be imposed by epitaxially depositing the material over another structure with a different lattice structure, such that the deposited layer has the lattice structure of the underlying structure. The acceptable degree of lattice strain within the deposited layer may be related to a variety of factors, including the thickness of the deposited layer, the degree of lattice mismatch between the deposited material and the underlying structure, and other factors. As used herein, "lattice mismatch" refers to the lattice mismatch in comparison between two structures. In some non - limiting embodiments, lattice strain within a heterolayer is generally a desirable property of an active device layer because it tends to increase the mobility of electrical carriers and thus increase device speed.

[0245] Such epitaxial layers can be optimized to reduce defects within the crystal structure. In one non - limiting example, relaxation of the strained layer may be accompanied by defect propagation, which may in turn impede device operation. Thus, the deposited epitaxial layer can be exposed to conditions that minimize relaxation of the deposited layer.

[0246] In one non - limiting example, each layer within the stack contains an epitaxial layer. In some embodiments, a structure having such layers can be considered a strained semiconductor structure.

[0247] In another non - limiting example, the thickness of the layer is controlled to minimize defects. For example, when the thickness of the strained layer increases beyond a "critical thickness" or h c c, defects appear within the crystal structure of the strained layer. When growth extends beyond this critical thickness, the increased strain may no longer be accommodated by the lattice mismatch and thus misfit dislocations are generated. The critical thickness depends on various factors, including the growth rate, growth temperature, composition of the layer (e.g., Si concentration, Ge concentration, or both Si and Ge concentrations), the amount of defects within the underlying layer, and the like.

[0248] As used herein, the term "silicon germanium" and "Si 1-x Ge x " and "SiGe" may refer to an alloy of silicon and germanium, where the ratio of germanium to silicon may be in the range of 1≥x>0. Non-limiting values of x include from about 0.01 to 0.6, from about 0.05 to 0.6, or from about 0.1 to 0.5. When deposited onto a single crystal Si substrate or layer, a larger amount of germanium generally increases the strain. Generally, the higher the Ge content within the layer (even a pure Ge layer), the greater the lattice mismatch with the underlying Si layer. For example, compared to a pure Si layer, the lattice constant of a pure Ge layer is 4.18% higher. When the thickness of the layer increases beyond its critical thickness h c , the layer will relax to its inherent lattice constant. Generally, such relaxation will result in misfit dislocations and other defects at or within the film interface. The critical thickness depends on the temperature (the higher the temperature, the lower the critical thickness) and the lattice mismatch caused by the germanium content (the higher the Ge concentration within the layer, the lower the critical thickness). For example, when a SiGe layer containing about 10 atomic percent (at.%) germanium is deposited at about 700 °C, it has a critical thickness of about for a balanced (steady state) strained film on Si <100>, and about for a metastable strained film. If strain needs to be maintained, the thickness is kept below the critical thickness, and generally a capping layer is applied to the strained heteroepitaxial layer during subsequent processing steps to maintain the (metastable) strain of the SiGe layer.

[0249] In certain instances, the stack includes a Si layer and a SiGe layer, and then the SiGe layer is etched away through further processing. Considering this processing, when the Ge concentration within the SiGe layer decreases, the selective etching of the SiGe layer (compared to the Si layer) becomes more difficult. Thus, in some instances, the SiGe layer includes an effective Ge concentration between about 2 atomic percent and 30 atomic percent. To achieve such a SiGe layer with a thickness below h c , two methods can be employed. First, a lower Ge content can be used, but there is a risk of reducing the etching selectivity. Second, a lower deposition temperature can be used, because a lower temperature provides a higher h c . For example, for a SiGe layer with a Ge content less than 27 atomic percent, the lattice mismatch is less than 1%; for a SiGe layer with a Ge content of about 15 - 27 atomic percent, h c is about 10 - 100 nm. In a particular embodiment, the stack includes a Si layer with a thickness of about 10 to 100 nm; or a SiGe layer with a thickness of about 5 to 50 nm.

[0250] Multiple strategies can be implemented to grow a low-strain epitaxial layer. For example, such conditions can promote growth of the layer at a low enough strain to prevent defects within the epitaxial layer (including Si or SiGe). Low-strain growth can include growth in a pseudomorphic mode, which can be characterized by the absence of corrugations and elastic strain tolerated by the lattice mismatch within the film. Such a mode can be used for layers and thin films with a small degree of misfit dislocations (e.g., having a thickness less than h c . In some embodiments, the defect can be characterized by having less than about 10 2 dislocations per cm 7 .

[0251] Other strategies can be implemented to grow a uniform epitaxial layer. For example, such conditions can include conditions for providing a layer with a uniform thickness (e.g., having a variation of less than about 2%). One example can include rotating the wafer during deposition, where susceptor rotation can reduce or eliminate azimuthal non-uniformity. Another example can include optimizing the showerhead hole (or aperture) pattern to achieve uniformity of fluid flux across the wafer surface. For example, the showerhead can include a plurality of holes arranged in a non-uniform pattern (e.g., including a pattern where the number of holes increases with radius). Yet another method can be to utilize multi-zone susceptor heating to ensure thermal uniformity of the wafer. In another instance, such conditions can include conditions for providing a film with a uniform Ge concentration within the layer. Further methods, devices, systems, conditions, reagents, methods, and processes are described in U.S. Patent No. 11,127,567, filed on May 4, 2020, and titled "Systems and methods for suppressing parasitic plasma and reducing within-wafer non-uniformity"; U.S. Patent Application No. 11,111,581, filed on May 13, 2019, and titled "Suppression of parasitic deposition in a substrate processing system by suppressing precursor flow and plasma outside of substrate region"; U.S. Patent Application No. 10,984,987, filed on October 10, 2018, and titled "Showerhead faceplate having flow apertures configured for hollow cathode discharge suppression"; U.S. Patent No. 10,358,722, filed on December 14, 2015, and titled "Showerhead assembly"; the entire contents of which are incorporated herein by reference.

[0252] This document describes other operations to facilitate the growth of heterolayers. In one embodiment, a pre-cleaning operation can be utilized to provide a clean substrate, for example, by removing oxides, carbon, metals, or other substances. Non-limiting substrates can include single-crystal substrates, silicon substrates, silicon-on-insulator (SOI) substrates, and the like. In another embodiment, a pre-treatment operation can be utilized to passivate the surface for growing the heterolayer. Other optional operations can include coplanarization (e.g., chemical mechanical polishing (CMP)), degassing of the chamber for accommodating the substrate, and the like.

[0253] Another operation can include a deposition operation to provide different heterolayers (e.g., by using low-temperature conditions). In certain embodiments, the deposition can include using a plasma (e.g., remote plasma, capacitively coupled plasma (CCP), inductively coupled plasma (ICP), transformer-coupled plasma (TCP), microwave plasma (MWP), low-energy plasma (LEP), low-temperature plasma (LTP), etc.) in the presence of various reactants (e.g., hydrogen-containing, deuterium-containing, ammonia-containing, deuterated ammonia-containing, or argon-containing reactants). During deposition, the plasma species can be transported through an ion filter before being delivered to the substrate. Optionally, such an ion filter can be used inside the showerhead.

[0254] During the deposition operation, low-temperature epitaxy can be employed (with or without plasma). In one example, the low-temperature epitaxy is performed at a temperature below about 700 °C or below about 650 °C or below about 600 °C. In certain embodiments, the epitaxy is performed at a temperature of about 350 °C to 550 °C, about 350 °C to 600 °C, about 350 °C to 650 °C, about 200 °C to 600 °C, about 200 °C to 650 °C, about 450 °C to 600 °C, or about 450 °C to 650 °C. Thermal control during deposition can include using any useful heater source, such as radiative heating using IR lamps, using LEDs, using front-side or back-side heating, using a wafer holder to achieve thermal uniformity and as a heat sink, and the like.

[0255] In other embodiments, the epitaxy is performed at a lower pressure. In a particular embodiment, the epitaxy is performed at a pressure of about 20 Torr or less.

[0256] Yet another operation can include a reactor cleaning operation, which can be used to clean the chamber or passivate the inner surface of the chamber configured to accommodate the substrate (e.g., during the pre-cleaning, pre-treatment, or deposition operations). Cleaning of the chamber can include using various reactants or plasmas to remove contaminants from the inner surface of the chamber. Passivation of the chamber can include using various reactants or plasmas to remove residual fluorine (or other halogens) from the chamber. Properties and characteristics of the stack

[0257] The vertical stack may include alternating first and second layers. The first layer may include a first material, and the second layer may include a second material different from the first material. Within the vertical stack, there may be multiple layers. In one example, the number of layers in the stack includes 10 layers, 20 layers, 30 layers or more.

[0258] The stack may have any useful height, such as about 1 μm to 10 μm or higher. Each layer within the stack may have any useful thickness (or height), and the thickness of each layer may be the same as or different from other layers. For example, each layer within the stack may have a thickness in the range of about 5 nm to 30 nm, but the first and second layers within the stack may have repeating or non-repeating thicknesses within this range to avoid defects or minimize strain. In some embodiments, the semiconductor layer has a thickness of about 20 nm to 40 nm. In other embodiments, the sacrificial layer has a thickness of about 8 nm to 12 nm.

[0259] In one example, the first layer includes a semiconductor layer. The semiconductor layer may include any useful material, such as Group IV materials, such as silicon (Si), germanium (Ge), tin (Sn), carbon (C), and their alloys or combinations; III-V materials, such as gallium arsenide (GaAs), indium phosphide (InP), indium arsenide (InAs), indium antimonide (InSb), gallium phosphide (GaP), aluminum phosphide (AlP), gallium nitride (GaN), aluminum nitride (AlN), aluminum gallium nitride (AlGaN), indium aluminum arsenide (InAlAs), indium gallium antimonide (InGaSb) and the like; and other hole mobility or electron mobility materials.

[0260] In another example, the second layer includes a sacrificial layer. The sacrificial layer may include any useful material, such as Group IV materials, such as Si, Ge or Sn; IV-IV materials, such as silicon germanium (SiGe), tin germanium (SnGe) and the like.

[0261] The selection of materials for the first and second layers may depend on the etch selectivity between the first and second materials. For example, using a stack including alternating Si layers and SiGe layers, etch conditions may be selected to remove the Si layer or the SiGe layer. In one non-limiting embodiment, a hydrogen plasma under certain conditions may be used to etch Si over SiGe. In other non-limiting embodiments, hydrogen chloride vapor may be used to etch SiGe over Si. Other etchant chemistries and conditions (such as any of those described herein) may be optimized to selectively etch the Si or SiGe layer.

[0262] The interface between the first and second layers can have any useful features. In some embodiments, an interface layer is present between the first and second semiconductor layers. Such an interface layer can be configured to reduce or prevent atomic diffusion between the first and second layers. The interface layer can include any of the materials described herein, such as group-IV materials, IV-IV materials (e.g., SiGe or other materials containing two different group-IV atoms), or doped forms thereof (e.g., having one or more group-III or group-IV or group-V atoms). In some embodiments, a doped interface layer is employed, and the concentration of dopant atoms (e.g., one or more group-III or group-IV or group-V atoms) can vary within the doped interface layer. In one embodiment, the concentration of dopant atoms increases near the first or second layer.

[0263] In other embodiments, a transition region exists between the first and second layers, where the atomic concentration can vary within this transition region. In another embodiment, the first and second layers together form a graded film. Within the transition region, the concentration of Si 1-x Ge x can vary from x = 0 to x = 0.5 and ranges therebetween. In other embodiments, the transition region has a thickness of less than about 2 nm, less than about 1 nm, or less than about 0.5 nm.

[0264] In one embodiment, the interface between the first and second layers can be processed. In one example, the substrate can be exposed to a plasma (e.g., any of those described herein), thereby providing a preparatory surface between the first and second semiconductor layers. This preparatory surface can provide a smoothed surface for depositing the next layer.

[0265] As described herein, the stack can include heterolayers, which in turn can include alternating first and second layers. The content of a particular atom within the stack can be understood as the in-layer concentration within a particular layer or as the effective concentration (or average concentration) within the entire stack. For the in-layer concentration, the average concentration of a particular atom within each layer or at least one layer can be determined. For the effective stack concentration, the concentration range of a particular atom within all layers of the stack can be determined, and the average concentration within this range can be determined.

[0266] The in-layer concentration and the effective stack concentration can be determined within a Si-SiGe stack, which can include alternating Si layers and SiGe layers. In one embodiment, within each SiGe layer or at least one SiGe layer, the in-layer concentration of Ge can be from about 5 atomic % to 40 atomic %. In other embodiments, the in-layer concentration is about 10 atomic % to 30 atomic %; 15 atomic % to 25 atomic %; or 15 atomic % to 40 atomic %.

[0267] The effective stacked concentration of Ge within these alternating layers will account for the Ge present in the SiGe layer and within multiple SiGe layers. In one embodiment, the effective stacked concentration of Ge can be from about 1.25 atomic % to 15 atomic %. In other embodiments, the effective stacked concentration of Ge is from about 1.25 atomic % to 10 atomic %, from about 2 atomic % to 10 atomic %, or from about 4 atomic % to 8 atomic %. If an interface layer is present (e.g., between a Si layer and a SiGe layer), the effective stacked concentration may be reduced when the interface layer does not include Ge. The interlayer concentration and the effective stacked concentration can be averaged or normalized values and need not account for concentration gradients or concentration distributions within the layer or stack.

[0268] In certain non - limiting embodiments, the stack can be formed from precursors, reagents, reactants, carrier gases, and inert gases, where halogens are avoided during deposition. Halogens or halogen - containing reactants can be employed during other operations that occur before or after deposition (e.g., other operations can include a pre - clean operation to remove oxides from the substrate, a pre - treatment operation to passivate the substrate surface, a reactor clean operation to clean the surfaces within the reactor chamber, or a reactor pre - treatment operation to remove halogens from the reactor chamber).

[0269] The stack can include further structural features that can be provided after depositing the vertical stack. For example, the vertical stack can include a capping layer to protect the deposited stack. In another example, the vertical stack can include a hard mask to facilitate further patterning or processing of the deposited stack.

[0270] In some embodiments, a first oxygen concentration measured from the substrate is comparable to a second oxygen concentration of at least one of the first semiconductor layer or the second semiconductor layer. In other embodiments, a first oxygen concentration measured from the substrate is substantially similar to a second oxygen concentration of at least one of the first semiconductor layer or the second semiconductor layer. In one instance, the first oxygen concentration value is from about 80% to 120%, 90% to 110%, or 95% - 105% of the second oxygen concentration value. If the second oxygen concentration is greater than the first oxygen concentration, a pre - clean operation (e.g., any of those described herein) can be used to treat the surface (e.g., of the substrate, the first semiconductor layer, or the second semiconductor layer). Selective etching of the sacrificial layer

[0271] After depositing the stack, further processes can be employed to remove certain layers. In one instance, selective etching conditions can be used to etch away the sacrificial layer while retaining the semiconductor layer. Such etching conditions can include dry processes, wet processes, or a combination of wet and dry processes to selectively remove the sacrificial layer after depositing the stack.

[0272] In one example, vapor HCl is used to selectively etch away the SiGe layer relative to the Si layer. In particular, the etch selectivity depends on the concentration of Ge in the SiGe layer and the etch temperature. Generally, the etch selectivity increases as the Ge concentration increases and the etch selectivity decreases as the etch temperature increases. Thus, in some examples, the Ge concentration in the SiGe layer can be selected to enhance the selective etching of SiGe within the stack. Non-limiting concentrations of Ge within the SiGe layer can include about 2% to 60%, about 2% to 50%, about 2% to 40%, about 2% to 30%, about 2% to 20%, about 3% to 60%, about 3% to 50%, about 3% to 40%, about 3% to 30%, about 3% to 20%, about 4% to 60%, about 4% to 50%, about 4% to 40%, about 4% to 30%, about 4% to 20%, about 5% to 60%, about 5% to 50%, about 5% to 40%, about 5% to 30%, about 5% to 20%, about 6% to 60%, about 6% to 50%, about 6% to 40%, about 6% to 30%, about 6% to 20%, about 8% to 60%, about 8% to 50%, about 8% to 40%, about 8% to 30%, about 8% to 20%, about 9% to 60%, about 9% to 50%, about 9% to 40%, about 9% to 30%, about 9% to 20%, about 10% to 60%, about 10% to 50%, about 10% to 40%, about 10% to 30%, about 10% to 20%, about 15%, about 25%, about 30% or less than about 20%, where the percentage values refer to atomic percentages.

[0273] Although a higher Ge concentration can enhance the selective etching, it may lead to an increase in the diffusion of Ge within the stack. Thus, in one example, to minimize the diffusion of Ge during deposition, a lower deposition temperature can be used to maintain uniformity from the top to the bottom within the stack.

[0274] In some embodiments, SiGe is selectively etched relative to Si. In one example, the etch rate of SiGe is higher than the etch rate of Si. In a particular embodiment, the ratio of the SiGe etch rate to the Si etch rate is greater than about 2:1, 5:1, 10:1, 25:1, 20:1 or 100:1. Such ratios can represent the etch selectivity of SiGe relative to Si.

[0275] In addition to acidic vapors, other etchant chemistries can be used. In one example, etching can include using a solution composed of hydrogen peroxide and acetic acid (CH3CO2H); a solution composed of an acid (such as HF), hydrogen peroxide, and acetic acid; a solution containing an etchant (such as an acid, such as HF or HCl) and at least one oxidizer (such as H2O2, HNO3, or peracetic acid (CH3CO3H)); plasma conditions containing a fluorocarbon source (such as CF4 or C4F8), which can optionally include nitrogen (N2), helium (He), or a combination of N2 and He; plasma conditions containing a fluorine source (such as F2 or NF3), which can optionally include nitrogen (N2), helium (He), or a combination of N2 and He; dry process conditions using an acid (such as HCl) and hydrogen (H2); and the like.

[0276] Within a vertical stack, a semiconductor layer (such as a sacrificial layer) can be removed, and the resulting void can be filled with an insulator or dielectric. Non-limiting insulator or dielectric materials can include silicon nitride, silicon oxide, silicon oxynitride, silicon carbide, silicon oxycarbide, silicon carbonitride, oxynitride, oxycarbide, carbonitride, or doped forms thereof (such as silicon carbide doped with oxygen, nitrogen, or both oxygen and nitrogen). As used herein, it should be understood that silicon oxide materials, silicon nitride materials, etc. include stoichiometric and non-stoichiometric forms of such materials, and such materials can have other elements incorporated therein, as described herein. Further, since the remaining semiconductor layer within the stack can serve as a channel or channel layer, an insulator or dielectric material can be used to isolate the channel. Pre-cleaning operation

[0277] Defects within the deposited layer (such as stacking defects, microtwins, inversion boundaries, and the like) can be minimized by appropriate pre-cleaning and pre-treatment of the substrate. In one example, defect control can be facilitated by using a pristine, oxide-free surface. Providing such a surface can include one or more pre-cleaning operations to remove oxides, carbon, metals, or other contaminants from the surface of the substrate.

[0278] The pre-cleaning operation can include any suitable cleaning process, such as a plasma-based oxide etching process, a dry etching process, a wet etching process, a sputter etching process, and combinations thereof.

[0279] The pre-clean operation may include a wet process, a dry process, or a combination of wet and dry processes to clean the substrate prior to deposition. For example, the pre-clean operation may include only a dry process, a combination of a wet process followed by a dry process, or a combination of a dry process followed by a wet process. In one example, the pre-clean operation includes using a halogen-containing reagent or other reagent in vapor form (e.g., a halogen vapor or halogen gas). In another example, the pre-clean operation includes using a halogen-containing reagent or other reagent in liquid form. In fact, any reagent herein can be provided in vapor form or liquid form.

[0280] In yet another example, the pre-clean operation includes using a reducing gas or a reducing gas plasma. Examples of reducing gas plasmas may include hydrogen plasmas. In a further example, the pre-clean operation includes using a hydride (e.g., any of those described herein). Examples of hydrides include silane (e.g., SiH4, Si2H6, or others described herein), germane (e.g., GeH4 or others described herein), and the like. Such hydrides may have the ability to remove trace oxides.

[0281] Such halogen-containing reagents may include fluorine-containing reagents such as hydrofluoric acid (HF), nitrogen trifluoride (NF3), chlorine trifluoride (ClF3), diatomic fluorine (F2), atomic fluorine (F*), ammonium fluoride (NH4F), ammonium bifluoride (NH4F:HF), and fluorinated hydrocarbons, which may be in liquid or gas form. In use, fluorine reacts with silicon oxide (SiO2) to provide silicon- and fluorine-containing substances that can desorb from the substrate surface. In one example, wet HF (e.g., aqueous HF or buffered HF) or diluted HF immersion is employed during the pre-clean operation. In another example, HF vapor is employed. In any example, a plasma may be used during the pre-clean process, as will be described below. Further reagents and conditions may be included as described in U.S. Patent Publication No. 2010 / 0184301 entitled "Methods for preventing precipitation of etch byproducts during an etch process and / or subsequent rinse process" and U.S. Patent No. 8,058,179 entitled "Atomic layer removal process with higher etch amount", the entire contents of each of which are incorporated herein by reference.

[0282] In some non-limiting examples, the halogen-containing reagent can be introduced directly into the chamber, rather than formed from ammonia and hydrogen fluoride or other reactants, such as ammonia (NH3), hydrogen fluoride (HF), hydrogen (H2), nitrogen trifluoride (NF3), nitrogen (N2), and water vapor (H2O). In certain embodiments, atomic hydrogen, atomic fluorine, atomic nitrogen, or a combination thereof can be generated in-situ and introduced into the chamber. For example, remotely generated nitrogen plasma can be introduced into the chamber.

[0283] Other additional halogen-containing reagents can include chlorine-containing reagents, such as hydrochloric acid (HCl), chlorine trifluoride (ClF3), diatomic chlorine (Cl2), monatomic chlorine, and chlorine-substituted hydrocarbons, which can be in liquid or gaseous form. In certain embodiments, the chlorine-containing reagent can be used in combination with a fluorine-containing reagent (e.g., HCl and HF).

[0284] The halogen-containing reagent can be used in combination with a hydrogen-containing reagent, which can be in liquid or gaseous form. Examples of such reagents include atomic hydrogen, molecular hydrogen, ammonia, hydrocarbons, and partially halogenated hydrocarbons (e.g., having at least one hydrogen atom in the hydrocarbon not substituted by a halogen atom).

[0285] Here, any hydrogen-containing reagent can be adjusted or replaced to provide a deuterium-containing reagent, which can be in liquid or gaseous form. Without wishing to be bound by mechanism, one benefit of deuterium is that the Si-D bond is more stable than the Si-H bond. Thus, in some instances, if a deuterium-containing reagent (including deuterium-containing gases, such as HD or D2) is used during a pre-cleaning operation, the presence of such Si-D bonds can provide a more stable surface.

[0286] The halogen-containing reagent can be used in combination with a solvent (in liquid or vapor form) and optionally an additive. The solvent can include polar solvents, such as water, isopropyl alcohol (IPA), ethanol, or methanol. The additive can include a base, such as pyridine. In a non-limiting embodiment, the pre-cleaning operation includes using a fluorine-containing reagent (e.g., HF), a solvent (e.g., IPA), and a heterocycle (e.g., pyridine).

[0287] Halogen-containing reagents can be used in combination with bases. Examples of bases include amino-containing reagents such as ammonia (NH3); hydrazine (N2H4); aliphatic amines such as primary amines (e.g., methylamine and ethylamine), secondary amines (e.g., dimethylamine and diethylamine), and tertiary amines (e.g., trimethylamine and triethylamine); aromatic amines such as aniline and methylaniline; alicyclic amines such as cyclohexylamine and dicyclohexylamine; heterocyclic amines such as pyrrole, pyrrolidine, pyrrolidone, pyridine, morpholine, pyrazine, piperidine, N-hydroxyethylpiperidine, oxazole, and thiazole.

[0288] The halogen-containing reagent can be a fluorine-containing reagent (e.g., HF) used with an amino-containing reagent (e.g., ammonia (NH3)). In some embodiments, when the fluorine-containing reagent is combined with the amino-containing reagent, a salt of the amino-containing reagent can be formed, such as an ammonium salt (e.g., NH4 + salt) or an ammonium fluoride salt (e.g., NH4 + F-). In other embodiments, the fluorine-containing reagent (e.g., HF) is used with two nitrogen-containing reagents (e.g., NF3 and NH3). In certain embodiments, the reagents can be used in a dry process using vapor. Further reagents and conditions can include those described in U.S. Patent Publication No. 2010 / 0184301 entitled "Methods for preventing precipitation of etch byproducts during an etch process and / or subsequent rinse process" and U.S. Patent No. 8,058,179 entitled "Atomic layer removal process with higher etch amount", the entire contents of each of which are incorporated herein by reference.

[0289] The halogen-containing reagent can be used with a carrier gas. Non-limiting carrier gases include hydrogen (H2), helium (He), argon (Ar), nitrogen (N2), and the like. In addition to the carrier gas, other gases or vapors can be present, such as water vapor or alcohol vapor. In one example, the halogen-containing reagent can be provided with the carrier gas and other optional gases at any useful temperature (e.g., about 30 °C to 60 °C) and any useful pressure (e.g., about 100 Torr to 300 Torr).

[0290] The pre-cleaning operation can be carried out at any useful temperature. In one embodiment, the temperature is higher than about 50 °C.

[0291] The pre-cleaning operation can include multiple steps, where at least one step uses a halogen-containing reagent and at least one step does not use such a reagent. The order of the steps can be any useful order, for example, an initial step without a halogen-containing reagent and subsequent steps using such a reagent; or an initial step including a halogen-containing reagent and subsequent steps without such a reagent.

[0292] The multi-step process can include any of the pre-cleaning conditions described herein (e.g., two, three, four or more) and in any available order. In one example, one of the conditions can include using a mixture of an oxidizing agent and an amino- or ammonium-containing reagent. For example, such a mixture can include a peroxide (e.g., hydrogen peroxide, H2O2) and an ammonium-containing reagent (e.g., ammonium hydroxide, NH4OH), which can be used to remove silicon, oxides, quartz, particles, and chemical impurities. Other conditions can include using a mixture of a halogen-containing reagent and an oxidizing agent. In one example, the mixture can include a chlorine-containing reagent (e.g., HCl) and a peroxide (e.g., H2O2) to remove metal or ionic or base contaminants. Any of these mixtures can include a solvent (e.g., a polar solvent, such as water or alcohol). Another condition can include using a dilute immersion solution including a halogen-containing acid (e.g., HF or HCl, which can be diluted with a solvent such as water) or a vapor treatment including a halogen-containing acid (e.g., HF or HCl).

[0293] In addition, any of the pre-cleaning conditions herein can be cycled and repeated. In one example, the cycle can include etching the substrate (e.g., thus producing Si- and halogen-containing substances as by-products) and an operation to remove such by-products. The operation of etching the substrate can be the same or different between cycles. In addition, the cycle can be repeated any number of times. In one example, the cycle is carried out once, twice, three times or more. In another example, each cycle removes about 10% to 40% of the total thickness of the substrate. In yet another example, each cycle removes about or less.

[0294] The pre-clean operation may include using a plasma (e.g., remote plasma, pulsed plasma, ICP, CCP, MWP, LEP, LTP, and the like) with a halogen-containing reagent, such as a chlorine-containing reagent or a fluorine-containing reagent. Exemplary chemicals may include, for example, chlorine- or fluorine-based plasma etchants, such as fluorinated hydrocarbons (e.g., CF4 or CHF3), chlorinated hydrocarbons (e.g., CCl4 or CHCl3), HF, HCl, NF3, sulfur hexafluoride (SF6), silicon tetrafluoride (SiF4), diatomic fluorine (F2), atomic fluorine, diatomic chlorine (Cl2), atomic chlorine, and the like; or, for example, nitrogen-based plasma etchants, such as NH3, NF3, and the like. In some embodiments, the halogen-containing reagent is used in combination with a hydrogen-containing reagent in the presence of a plasma (e.g., to provide hydrogen radicals, H*). In other embodiments, the halogen-containing reagent (e.g., NF3) is used in combination with an amino-containing reagent (e.g., NH3) in the presence of a plasma. In still other embodiments, any of the chemicals herein may be used in the presence of a plasma. The plasma may be used with a carrier gas or an inert gas, such as any of those described herein (e.g., H2, He, Ar, N2, and the like).

[0295] In one example, a fluorine-containing reagent (e.g., NF3) is used with hydrogen radicals to produce an intermediate species (e.g., NH x F y ), which reacts with silicon oxide to produce a byproduct (e.g., (NH4)2SiF6) that can be pyrolyzed (e.g., at about 100 °C or higher temperature) or sublimed (e.g., at about 100 °C or higher temperature). The pyrolysis products (e.g., HF or SiF4) can in turn be evaporated using a further baking step. In other examples, a fluorine-containing reagent (e.g., NF3) is used with helium to produce a plasma. Further reagents and conditions may include those described in U.S. Patent Publication No. 2010 / 0184301, entitled "Methods for preventing precipitation of etch byproducts during an etch process and / or subsequent rinse process" and U.S. Patent No. 8,058,179, entitled "Atomic layer removal process with higher etch amount", the entire contents of each of which are incorporated herein by reference.

[0296] The plasma may be employed independently of the halogen-containing reactant to remove carbon, oxygen, or other contaminants from the substrate. For example, the pre-clean operation may include first exposing the substrate to the halogen-containing reactant and then exposing the substrate to the plasma.

[0297] Any plasma mode or configuration can be employed, such as any plasma mode or configuration described herein, including electron cyclotron resonance (ECR) hydrogen plasma, RF plasma, or remote plasma. In some embodiments, the plasma is used at a temperature in the range of about 20 °C to 500 °C; a pressure in the range of about 5 mTorr to 200 mTorr; or an RF power in the range of about 50 W to 1000 W, and any combination of these conditions. Other temperature and pressure ranges are described herein. Any useful plasma removal and ashing conditions can be implemented. In one example, an Ar-based plasma etch can be employed (e.g., at a pressure of about 5 mTorr to 20 mTorr, a source power of about 1000 W, and a bias power of 200 W).

[0298] In addition to the plasma, other energy sources can be used alone or in combination with halogen-containing reagents. For example, ultraviolet light (UV), deep ultraviolet light (DUV), or extreme ultraviolet light (EUV) radiation can be employed to generate, for example, free radicals, metastable species, and the like. In one example, ultraviolet light and ozone can be used to remove organic contaminants. In another example, ultraviolet light and a halogen-containing reagent (such as chlorine gas, Cl2) are used to remove metal contaminants. In yet another example, the etch can include using UV with NF3 and H2, which can optionally be followed by an Ar-based etch.

[0299] Etching processes, including plasma-based etching processes, typically produce by-products (e.g., vaporized by-products) that can then be removed. The by-products can be removed by sublimation (e.g., raising the substrate temperature to about 300 °C or higher). The by-products can optionally be pyrolyzed (e.g., raising the substrate temperature to about 100 °C or higher), and then the pyrolyzed by-products can be removed. Plasma etching processes result in the substrate surface having silicon-hydrogen (Si-H) bonds.

[0300] After the pre-cleaning operation, further operations can be performed to provide an oxide-free substrate. For example, a baking step or an annealing step can be carried out to reduce the water vapor or sublimated reactive by-products on the substrate surface, thus providing a contaminant-free surface. In another example, raising the temperature of the cleaned substrate can inhibit surface oxidation, especially in the presence of a non-oxidizing environment (e.g., in an environment with N2 or Ar).

[0301] The non-limiting baking step can include using a temperature higher than about 800 °C, such as about 800 °C to 950 °C; or a temperature higher than about 100 °C. Optionally, the baking step can be carried out in the presence of H2 gas. In some examples, the pre-cleaning operation includes immersing the substrate in diluted HF, followed by baking or annealing.

[0302] Another non-limiting baking step may include suppressing oxide formation at a temperature of about 350 °C at a pressure less than 1 Torr, followed by heating to a temperature of about 350 °C to 530 °C in the presence of a precursor (e.g., an Si-containing precursor). Without wishing to be bound by theory, such processes may promote Si-Si bond formation rather than Si-O bond formation, where O may be provided by residual water vapor (H2O) or oxygen (O2) present in the environment.

[0303] Any useful process may be employed to remove oxides, contaminants, or other undesired components from the substrate surface without significantly damaging the substrate. The substrate may include a single crystal surface or a non-single crystal surface (e.g., a polycrystalline or amorphous surface). Non-limiting single crystal surfaces may include bare crystal substrates or deposited single crystal layers typically made of materials such as silicon, germanium, silicon germanium, or silicon carbide. Polycrystalline or amorphous surfaces may include dielectric materials such as oxides or nitrides, particularly silicon oxides or silicon nitrides, and amorphous silicon surfaces. Examples of vapor-based pre-cleaning operations

[0304] In various embodiments herein, a mixture of vapor phase reactants is used to pre-clean (or etch) a semiconductor substrate, comprising: (1) a halogen source, such as hydrogen fluoride; (2) an organic solvent, water, or a combination thereof; (3) an additive; and (4) a carrier gas. In other embodiments, the mixture of vapor phase reactants comprises (1) a halogen source, such as hydrogen fluoride; (3) an additive; and (4) a carrier gas. In still other embodiments, the mixture of vapor phase reactants comprises (1) a halogen source, such as hydrogen fluoride; (2) an organic solvent, water, or a combination thereof; and (3) an additive. As used herein, the terms "vapor phase" and "gas phase" may be used interchangeably in this disclosure.

[0305] The additive may have specific properties or a specific composition, as further described below. In some non-limiting embodiments, the additive acts as a catalyst, which is generally used for the purpose of accelerating the reaction rate or improving the reaction selectivity. Examples of additives include heterocyclic compounds, heteroaromatic compounds, halogen-substituted heteroaromatic compounds, heterocyclic aliphatic compounds, amines, fluoroamines, amino acids, organophosphorus compounds, oxidants, difluoride sources, ammonia, aldehydes, carbenes, or organic acids, and other additives described herein.

[0306] The substrate may be etched at low pressure using thermal energy, such as in a vacuum reaction chamber. In such examples, the substrate is not exposed to plasma during the etching reaction. The substrate may be etched in a selective manner such that one or more materials are targeted for removal while other materials are etched to a lesser extent. One advantage of the disclosed technology is its high selectivity during etching. Another advantage of the disclosed technology is its extremely precise etching control.

[0307] The vapor-phase materials delivered to the reaction chamber can be collectively referred to as a gas mixture. The non-inert materials (e.g., reactants other than the carrier gas) delivered to the reaction chamber can be collectively referred to as a reactant mixture. The gas mixture includes the reactant mixture and the carrier gas. In some examples, the reactant mixture or the gas mixture can have a specific composition. For example, hydrogen fluoride or other halogen sources can be provided in the reactant mixture at a concentration between about 20-100% (by volume) or between about 20-99% (by volume). In these or other examples, hydrogen fluoride or other halogen sources can be provided in the gas mixture at a concentration between about 0.5-20% (by volume). Organic solvents or water can be provided in the reactant mixture at a concentration between about 10-100% (by volume) or between about 10-99% (by volume). In these or other examples, organic solvents or water can be provided in the gas mixture at a concentration between about 0-10% (by volume). Additives can be provided in the reactant mixture at a concentration between about 0.2-5% (by volume). In these or other examples, additives can be provided in the gas mixture at a concentration between about 0-0.2% or between about 0.0001-0.2% (by volume). The carrier gas can be provided in the gas mixture at a concentration between about 0-99% (by volume).

[0308] In some embodiments, the additive is mixed with an organic solvent or water such that the additive accounts for between about 0.1-5% (by weight) of the additive / organic solvent or water mixture. Regardless of the mixing order, the reactant mixture can be characterized in that the additive is about 0.1-5% (by weight) of the total amount of the additive and the organic solvent or water.

[0309] In the same or alternative embodiments, the reactant mixture can be characterized by the ratio of halogen source:additive (by volume). As further described below, in some embodiments, selectivity can be adjusted by the volume ratio of halogen source:additive, and selectivity increases as the amount of additive added increases (and thus the ratio decreases). In some embodiments, the ratio of halogen source:additive is less than or equal to 10. In some embodiments, the ratio of halogen source:additive is greater than 10.

[0310] According to various embodiments, the reactant mixture can include a halogen source, an alcohol (a non-limiting organic solvent), and an amine (a non-limiting additive), wherein the amine accounts for between 0.1-5% (by weight) of the total amount of the alcohol and the amine. In some embodiments, the volume ratio of halogen source:amine is not greater than 10. In other embodiments, the volume ratio of halogen source:amine is 10 or higher. In some embodiments, the amine is pyridine. In some embodiments, the alcohol is isopropyl alcohol. In some embodiments, the halogen source is HF. In some instances and under certain conditions, the alcohol and the amine combine to form an adduct or reaction product within the reactant mixture.

[0311] As described above, according to various implementations, etching can be selective for one material on a substrate relative to another material. In other implementations, etching can be non-selective with respect to multiple materials on the substrate.

[0312] In some embodiments, an oxide is etched selectively relative to one or more of a nitride and an epitaxial material (such as Si and SiGe). The etch selectivity of the reactant mixture for silicon oxide can be adjusted by the dosage in the mixture. For example, a reactant mixture having a halogen source: additive ratio of no more than 10 (e.g., HF:pyridine) is used to achieve a very high (at least 50:1) etch selectivity of silicon oxide relative to silicon nitride. The etch selectivity decreases as the ratio increases, such that non-selectivity is observed in the example without an additive. A similar effect can be observed for the etch selectivity of silicon oxide relative to Si and SiGe.

[0313] In some embodiments, a low-k material is etched selectively relative to a barrier material. For example, a carbon-doped silicon oxide material can be etched selectively relative to a barrier material such as a titanium nitride layer.

[0314] The temperature can be controlled using several techniques that can be combined as needed, such as by controlling the temperature of the substrate support, the showerhead, the reaction chamber walls, the process gas, etc. In one example, the substrate support, the showerhead, the reaction chamber walls, the process gas, and the like can be configured to be cooled (e.g., by using cooling elements, which can include using a coolant, a cooling gas, a cooler, a cooling zone having a heat transfer liquid flowing through pipes disposed within the zone), and the like). In another example, when a cyclic etching technique is used, the temperature can cycle between two or more different settings. In some embodiments, the temperature during a modification period for modifying the surface can be between about 100 - 500 °C, while the temperature during a vapor etching period can be between about 20 - 200 °C. In various implementations, the substrate is not exposed to plasma. In such embodiments, the reactions occurring during the modification period and the reactions occurring during the vapor etching are both thermally driven.

[0315] The etching operation can be performed in a self-limiting manner. For example, the gas mixture provided during vapor etching can selectively etch the modified material formed during the modification period. Once the modified material is consumed, the etch rate can be significantly reduced or even stopped due to the selective nature of the etching process. Thus, in certain embodiments, the etching process can be considered self-limiting. Further, as described above, the etching process can selectively target the material to be removed, while substantially not removing other materials present on the substrate.

[0316] The methods described herein can be performed on any suitable device. The following description provides an example of a suitable device. The devices described herein allow for rapid and precise control of the temperature of a substrate during semiconductor processing, including etching using thermal energy rather than plasma energy or in addition to plasma energy to drive modification and removal operations. In certain embodiments, etching that relies primarily on chemical reactions that incorporate thermal energy rather than plasma to drive chemical reactions in modification and removal operations can be considered "thermal etching". This etching is not limited to ALE (atomic layer etching); it can be applied to any etching technique.

[0317] In certain embodiments, thermal etching processes (such as those employing one or more thermal cycles) have relatively rapid heating and cooling and relatively precise temperature control. In some examples, these characteristics can be utilized to provide good throughput or reduce non-uniformity and wafer defects.

[0318] Many conventional etching devices do not have the ability to adjust and control the temperature of a substrate at a sufficient rate. For example, while some etching devices may be able to heat a substrate to multiple temperatures, they can only do so slowly, or they may not be able to reach the desired temperature range, or they may not be able to maintain the substrate temperature within the desired time and temperature range. Similarly, typical etching devices often cannot cool a substrate quickly enough to achieve high throughput or cool the substrate to the desired temperature range. For some applications, it is desirable to minimize the temperature ramp time, for example to less than about 120 seconds in some embodiments, but many conventional etching devices cannot heat, cool, or heat and cool a substrate in less than this time; some devices may take several minutes to cool or heat a substrate, thereby reducing throughput.

[0319] In various embodiments, the devices described herein are designed or configured to rapidly heat and cool a wafer and precisely control the temperature of the wafer. In some embodiments, the wafer is rapidly heated and its temperature is precisely controlled in part using visible light or infrared light emitted from light emitting diodes (LEDs) in a pedestal located beneath the wafer. The visible light can have a wavelength that encompasses and ranges between 400 nanometers (nm) and 800 nm. The infrared light can have a wavelength that encompasses and ranges between 700 nm and 1000 nm. In certain embodiments, the LEDs can be configured to provide light having a wavelength of about 400 nm to 1000 nm or 500 nm to 1000 nm.

[0320] The susceptor may include various features for implementing wafer temperature control, such as a transmissive window having a lens for advantageously directing or focusing the emitted light, a reflective material also for advantageously directing or focusing the emitted light, and a temperature control element for assisting in the temperature control of the LED, susceptor, and chamber. In another embodiment, the LED is formed of a material that is transmissive to visible light and resistant to damage or etching caused by the reactor cleaning or reactor processing operations described herein.

[0321] For example, heater LEDs can be used to emit visible light or infrared radiation onto the backside of the substrate, thereby heating the substrate. Visible light having a wavelength of about 400 nm to 800 nm can rapidly and effectively heat a silicon wafer from ambient temperature (e.g., about 20 °C) to about 600 °C because silicon absorbs light in this range. In contrast, radiative heating (including infrared radiation) may not be able to effectively heat silicon to temperatures up to about 400 °C because silicon tends to be transparent to infrared radiation at temperatures below about 400 °C. Additionally, radiative heaters that directly heat the top side of the wafer (as in many conventional semiconductor processes) may cause damage or other adverse effects to the top side film. Conventional "hot plate" heaters that rely on solid-to-solid heat transfer between the substrate and the heating plate (e.g., a susceptor having heating coils) have relatively slow heating and cooling rates and provide non-uniform heating, which may be caused by substrate warping and inconsistent contact with the heating plate. For example, it may take several minutes to heat a conventional susceptor to a desired temperature, from a first to a second higher temperature, and to cool the susceptor to a lower temperature.

[0322] The plurality of LEDs of the heater can be arranged, electrically connected, and electrically controlled in various ways. Each LED can be configured to emit visible blue light or visible white light. In certain embodiments, white light (produced using a wavelength range in the visible portion of the electromagnetic (EM) spectrum) is used. In some semiconductor processing operations, white light can reduce or prevent unwanted thin film interference. For example, the backside film of some substrates reflects light of different wavelengths in different amounts, resulting in non-uniform and potentially inefficient heating. Using white light can reduce this unwanted reflection variation by averaging the thin film interference over the broad visible spectrum provided by the white light. In some instances, depending on the material on the backside of the substrate, using visible non-white light (e.g., blue light having a wavelength of 450 nm) may be advantageous, for example, to provide a single or narrow band wavelength that can provide more effective, more powerful, and direct heating for some substrates that may absorb the narrow band wavelength better than white light.

[0323] Various types of LEDs can be employed. Examples include chip-on-board (COB) LEDs or surface-mounted diodes (SMD) LEDs. For SMD LEDs, the LED chips can be fused to a printed circuit board (PCB) that can have multiple electrical contacts to control the individual diodes on the chip. For example, a single SMD chip is typically limited to having three diodes (e.g., red, blue, or green), which can be individually controllable, for example, to produce different colors. The SMD LED chip size ranges can be, for example, 2.8x2.5 mm, 3.0x3.0 mm, 3.5x2.8 mm, 5.0x5.0 mm, and 5.6x3.0 mm. For COB LEDs, each chip can have more than three diodes (e.g., nine, twelve, ten, hundreds, or more) printed on the same PCB. Regardless of the number of diodes, COB LED chips typically have a circuit and two contacts, thus providing a simple design and efficient monochromatic applications. The ability and performance of the LED to heat the substrate can be measured by the thermal watts emitted by each LED; the heat of these watts can directly contribute to heating the substrate.

[0324] The apparatus can also thermally isolate or thermally "float" the wafer within the processing chamber such that only a minimal thermal mass is heated, ideally only the substrate itself, which enables faster heating and cooling. As used herein, the terms "thermally isolate" or "thermally float" mean to substantially isolate an object to ensure rapid heat transfer to the object. The wafer can be rapidly cooled using a cooling gas and transferring radiant heat to a heat sink (e.g., a top plate (or other gas distribution element) above the wafer or both). In some instances, the apparatus further includes temperature control elements within the processing chamber walls, the pedestal, and the top plate (or other gas distribution element) to enable further temperature control of the wafer and processing conditions within the chamber, such as preventing unwanted condensation of process gases and vapors.

[0325] In some embodiments, pre-cleaning includes providing a gas mixture (e.g., any of those described herein) in the reaction chamber and exposing the substrate to the gas mixture, and the pressure in the reaction chamber is between about 0.2 - 10 Torr. In certain embodiments, the gas mixture is in the vapor phase. In some instances, pre-cleaning further includes providing thermal energy to the reaction chamber to drive a reaction that etches the target material from part or all of the substrate, where the substrate is not exposed to plasma during etching. In other embodiments, pre-cleaning further includes exposing the substrate to plasma during etching. Further conditions and reagents are described in International Publication No. WO 2021 / 202411 named "Selective precision etching of semiconductor materials", the entire content of which is incorporated herein by reference. Halogen source

[0326] The halogen source can be any halogen-containing (e.g., containing X, where X is fluorine (F), chlorine (Cl), bromine (Br), or iodine (I)) compound that exists in the vapor phase at the processing temperature. Examples include hydrogen fluoride (HF), hydrogen chloride (HCl), hydrogen bromide (HBr), fluorine (F2), chlorine (Cl2), bromine (Br2), chlorine trifluoride (ClF3), nitrogen trifluoride (NF3), nitrogen trichloride (NCl3), and nitrogen tribromide (NBr3). In some implementations, the halogen source is an organic halide, examples of which include fluoroform (CHF3), chloroform (CHCl3), bromoform (CHBr3), carbon tetrafluoride (CF4), carbon tetrachloride (CCl4), carbon tetrabromide (CBr4), perfluorobutene (C4F8), and perchlorobutene (C4Cl8). In some implementations, the halogen source is a silicon halide, examples of which include silicon tetrafluoride (SiF4), silicon tetrachloride (SiCl4), silicon tetrabromide (SiBr4), and compounds including SiX6 (e.g., H2SiX6). In some implementations, the halogen source is a metal halide, examples of which include molybdenum hexafluoride (MoF6), molybdenum hexachloride (MoCl6), molybdenum hexabromide (MoBr6), tungsten hexafluoride (WF6), tungsten hexachloride (WCl6), tungsten hexabromide (WBr6), titanium tetrafluoride (TiF4), titanium tetrachloride (TiCl4), titanium tetrabromide (TiBr4), zirconium fluoride (ZrF4), zirconium chloride (ZrCl4), and zirconium bromide (ZrBr4). Metal halides can be used in some embodiments to selectively etch metal oxides.

[0327] In the following description, various examples include HF as the halogen source. However, any suitable halogen source can be used. The volume and mass percentages described for HF can be used for other halogen sources. In some embodiments, two or more halogen sources can be used. Organic solvent

[0328] In certain implementations, the organic solvent can be an alcohol. The alcohol can be an alcohol having the formula X-C(R) n (OH)-Y, where: n is 1; Each X and Y can independently be selected from hydrogen, -[C(R 1 )2] m -C(R 2 )3 or OH, where each R 1 and R 2 are independently selected from hydrogen, hydroxyl, aliphatic, haloaliphatic, haloheteroaliphatic, heteroaliphatic, aromatic, aliphatic-aromatic, heteroaliphatic-aromatic, or any combination thereof, and where m is an integer from 0 to 10; and Each R is independently selected from hydrogen, hydroxyl, aliphatic, haloaliphatic, haloheteroaliphatic, heteroaliphatic, aromatic, aliphatic-aromatic, heteroaliphatic-aromatic, or any combination thereof.

[0329] In some embodiments, each R, R 1 and R 2 are independently selected from alkyl, alkenyl, alkynyl, heteroalkyl, heteroalkenyl, heteroalkynyl, haloalkyl, haloalkenyl, haloalkynyl, halohaloalkyl, halohaloalkenyl, halohaloalkynyl, aryl, heterocyclic, heteroaryl, alkyl-aryl, alkenyl-aryl, alkynyl-aryl, alkyl-heterocyclic, alkenyl-heterocyclic, alkynyl-heterocyclic, alkyl-heteroaryl, alkenyl-heteroaryl, alkynyl-heteroaryl, heteroalkyl-aryl, heteroalkenyl-aryl, heteroalkynyl-aryl, heteroalkyl-heterocyclic, heteroalkenyl-heterocyclic, heteroalkynyl-heterocyclic, heteroalkyl-heteroaryl, heteroalkenyl-heteroaryl, heteroalkynyl-heteroaryl or any combination thereof. In certain disclosed embodiments, the alcohol may be further substituted with one or more substituents such as alkoxy, amide, amine, thioether, thiol, acyloxy, silyl, cycloaliphatic, aryl, aldehyde, ketone, ester, carboxylic acid, acyl, acyl halide, cyano, halogen, sulfonate, nitro, nitroso, quaternary amine, pyridyl (or pyridyl in which the nitrogen atom is functionalized with aliphatic or aryl), haloalkyl or any combination thereof.

[0330] In other embodiments, when at least one of X or Y = -[C(R 1 )2] m -C(R 2 )3 or R is hydrogen and m is 1, the alcohol may be a C3 alcohol. For example, if at least one R 1 and one R 2 are absent, the C3 alcohol may be a C3 enol (e.g., allyl alcohol). In another example, R together with one R 2 may form a ring (e.g., cycloaliphatic), then the C3 alcohol may be cyclopropanol or 2-cyclopropenol.

[0331] In still other embodiments, when at least one of X or Y = -[C(R 1 )2] m -C(R 2 )3 or R is hydrogen and m is 2, the alcohol may be a C4 alcohol. For example, if at least one R 1 and one R 2 are absent, the C4 alcohol may be a C4 enol (e.g., 2-buten-1-ol or 3-buten-1-ol). In another example, R together with one R 2Together they can form a ring (e.g., cycloaliphatic), then the C4 alcohol can be a C4-cyclic alcohol (e.g., cyclobutanol or cyclopropylmethanol). In another example, if neither X nor Y is OH, the C4 alcohol can be a C4-branched alcohol (e.g., 2-butanol, isobutanol, or tert-butanol).

[0332] The alcohol can be a diol having two OH groups. The OH groups can be located anywhere within the compound, provided that only two OH groups are provided for the diol. In one example, R = OH, and neither X nor Y contains an OH group. In another example, X includes an OH group, and neither R nor Y includes an OH group. In some examples, when X = OH, Y = -[C(R 1 )2] m -C(R 2 )3, R ≠ OH, R1 ≠ OH, and R 2 ≠ OH, then the alcohol can be a diol. In some examples, when X = OH, Y = -[C(R 1 )2] m -C(R 2 )3, R ≠ H, R 1 ≠ OH, and R 2 ≠ OH, then the alcohol can be a diol. In still other examples, when X and R do not include OH, Y = -[C(R 1 )2] m -C(R 2 )3 and at least one R 1 = OH or one R 2 = OH, then the alcohol can be a diol. In other examples, when X does not include OH, Y = -[C(R 1 )2] m -C(R 2 )3, R 1 ≠ OH, R 1 ≠ OH, and R = OH, the alcohol can be a diol. Exemplary diols include but are not limited to 1,4-butanediol, 1,3-propanediol, and the like.

[0333] The alcohol can be a triol having three OH groups. The OH groups can be located anywhere within the compound, provided that only three OH groups are provided for the triol. In one example, R and X include OH, and Y does not include an OH group. In other examples, when X = Y = OH and R ≠ OH, the alcohol can be a triol. In still other examples, when X = R = OH and Y does not include OH, the alcohol can be a triol. In some examples, when X and R do not include OH, Y is -[C(R 1 )2] m -C(R 2 )3 and one R 1 and at least one R 2When R is OH, the alcohol can be a triol. In other instances, when R = OH, Y does not include OH, and X = -[C(R 1 )2] m -C(R 2 )3 and at least one R 1 = OH or one R 2 = OH, the alcohol can be a triol. Exemplary triols include, but are not limited to, glycerol, propanetriol, 1,1,2-ethanetriol, 1,1,1-ethanetriol, and the like.

[0334] In certain embodiments, when R is cycloaliphatic, heterocyclic, heteroaryl, alkyl-heterocyclic, alkenyl-heterocyclic, alkynyl-heterocyclic, heteroalkyl-heterocyclic, heteroalkenyl-heterocyclic, or heteroalkynyl-heterocyclic, the alcohol can be a heterocyclic alcohol (e.g., an optionally substituted heterocyclic group substituted with one or more hydroxyl groups, such as furfuryl alcohol). In other embodiments, when at least one of X or Y is -[C(R 1 )2] m -C(R 2 )3 and one R 1 and at least one R 2 is cycloheteroaliphatic, heterocyclic, heteroaryl, alkyl-heterocyclic, alkenyl-heterocyclic, alkynyl-heterocyclic, heteroalkyl-heterocyclic, heteroalkenyl-heterocyclic, or heteroalkynyl-heterocyclic, the alcohol can be a heterocyclic alcohol.

[0335] In various embodiments, the alcohol can have 1 - 10 carbon atoms. The alcohol can be a primary alcohol, secondary alcohol, or tertiary alcohol. In some examples, the alcohol can be selected from the group consisting of methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, tert-butanol, 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, 1-decanol, and combinations thereof.

[0336] In these or other examples, the organic solvent can include laboratory-type solvents such as acetonitrile, dichloromethane, carbon tetrachloride, or combinations thereof.

[0337] In some embodiments, the organic solvent can be a ketone. The organic solvent can also be a ketone having the formula X-[C(O)] n -Y, wherein: n is an integer from 1 to 2; each X and Y can independently be selected from -C(R 1 )3, -R 2 or -[C(R 3 )2] m -C(O)-R 4 , wherein each R 1 , R 2 , R 3 and R 4may be independently selected from hydrogen, hydroxyl, aliphatic, haloaliphatic, haloheteroaliphatic, heteroaliphatic, aromatic, aliphatic-aromatic, heteroaliphatic-aromatic, or any combination thereof; wherein R 3 and R 4 together with the atoms to which they are attached may optionally form cycloaliphatic or cycloheteroaliphatic, and wherein X and Y together with the atoms to which they are attached may optionally form cycloaliphatic or cycloheteroaliphatic; and m is an integer from 0 to 10.

[0338] In some embodiments, each R 1 , R 2 , R 3 and R 4 is independently selected from alkyl, alkenyl, alkynyl, heteroalkyl, heteroalkenyl, heteroalkynyl, haloalkyl, haloalkenyl, haloalkynyl, halohaloalkyl, halohaloalkenyl, halohaloalkynyl, aryl, heterocyclic, heteroaryl, alkyl-aryl, alkenyl-aryl, alkynyl-aryl, alkyl-heterocyclic, alkenyl-heterocyclic, alkynyl-heterocyclic, alkyl-heteroaryl, alkenyl-heteroaryl, alkynyl-heteroaryl, heteroalkyl-aryl, heteroalkenyl-aryl, heteroalkynyl-aryl, heteroalkyl-heterocyclic, heteroalkenyl-heterocyclic, heteroalkynyl-heterocyclic, heteroalkyl-heteroaryl, heteroalkenyl-heteroaryl, heteroalkynyl-heteroaryl or any combination thereof. In certain disclosed embodiments, the organic solvent may be further substituted with one or more substituents such as aldehyde (-C(O)H), oxo (=O), alkoxy, amide, amine, hydroxyl, thioether, thiol, acyloxy, silyl, cycloaliphatic, aryl, aldehyde, ketone, ester, carboxylic acid, acyl, acyl halide, cyano, halogen, sulfonate, nitro, nitroso, quaternary amine, pyridyl (or pyridyl in which the nitrogen atom is functionalized with aliphatic or aryl), haloalkyl or any combination thereof. An exemplary ketone is acetone.

[0339] In some embodiments, when X and Y together with the atoms to which they are attached form cycloaliphatic or cycloheteroaliphatic, the organic solvent may be a cyclic ketone. Examples of cyclic ketones include cyclohexanone, cyclopentanone and the like.

[0340] In other embodiments, when at least one of X or Y = -[C(R 3 )2] m -C(O)-R 4 the organic solvent may be a diketone. Exemplary diketones include diacetyl, 2,3-pentanedione, 2,3-hexanedione, 3,4-hexanedione, acetylacetone, acetonylacetone and the like, and halogenated forms thereof such as hexafluoroacetylacetone.

[0341] In further embodiments, when at least one of X or Y = -[C(R 3 )2]m -C(O)-R 4 When X and Y together with the atoms to which they are attached form a cycloaliphatic or cycloheteroaliphatic group, the organic solvent can be a cyclic diketone. Exemplary cyclic diketones include dimedone, 1,3 - cyclohexanedione, and the like.

[0342] In some instances, when X = -CH3, the organic solvent can have Y = -C(R 1 )3, where at least one R 1 is C 2-10 hydroxy, aliphatic, haloaliphatic, halocycloheteroaliphatic, cycloheteroaliphatic, aromatic, aliphatic - aromatic, cycloheteroaliphatic - aromatic, or any combination thereof. Exemplary materials can include methyl propyl ketone, methyl butyl ketone, hydroxyacetone, and the like.

[0343] In other instances, when X = -CH3, the organic solvent can have Y = -R 2 , where at least one R 1 is C 2-10 hydroxy, C 3-10 aliphatic, haloaliphatic, halocycloheteroaliphatic, cycloheteroaliphatic, aromatic, aliphatic - aromatic, cycloheteroaliphatic - aromatic, or any combination thereof. Exemplary materials can include methyl vinyl ketone, methyl propyl ketone, methyl butyl ketone, and the like.

[0344] In still other instances, when at least one of X or Y = aromatic, or aliphatic - aromatic, or cycloheteroaliphatic - aromatic, the organic solvent can be an aromatic ketone. Exemplary materials include acetophenone, benzophenone, benzyl acetone, 1,3 - diphenylacetone, cyclopentyl phenyl ketone, and the like.

[0345] In certain instances where the organic solvent includes a ketone, the ketone can be selected from acetone and acetophenone. One or more additional ketones or other organic solvents as described herein can also be provided.

[0346] In some embodiments, the organic solvent can be an alkane. In certain embodiments, the alkane can be an acyclic branched or unbranched hydrocarbon having the general formula C n H 2n+2 . Exemplary acyclic alkanes include but are not limited to pentane, hexane, octane, and combinations thereof. In certain other embodiments, the alkane can be a cycloalkane. Exemplary cycloalkanes include but are not limited to cyclopentane, cyclohexane, and combinations thereof.

[0347] In some embodiments, the organic solvent can be an aromatic solvent. As used herein, "aromatic" means a cyclic conjugated group or moiety having 5 to 15 (unless otherwise specified) ring atoms in a single ring (e.g., phenyl) or multiple fused rings, where at least one ring is aromatic (e.g., naphthyl, indolyl, or pyrazolopyridinyl); that is, at least one ring and optionally multiple fused rings have a continuous and delocalized π - electron system. Generally, the number of out - of - plane π - electrons corresponds to the Hückel rule (4n + 2). The point of attachment to the parent structure is typically through the aromatic portion of the fused - ring system. In some instances, the aromatic solvent can be selected from toluene and benzene.

[0348] In some embodiments, the organic solvent can be an ether having the formula X - O - Y or X - O - [C(R)2] n - O - Y, where: n is an integer from 1 to 4; Each X and Y can independently be selected from - [C(R 1 )2] m1 - C(R 2 )3 or - R 3 or - [C(R 4 )2] p - O - [C(R 5 )2] m2 - C(R6)3, where each R 1 、R 2 、R 3 、R 4 、R 5 、R 6 and R can independently be selected from hydrogen, hydroxyl, aliphatic, haloaliphatic, haloheteroaliphatic, heteroaliphatic, aromatic, aliphatic - aromatic, heteroaliphatic - aromatic, or any combination thereof, and where m1 is an integer from 0 to 10, m2 is an integer from 0 to 10, and p is an integer from 1 to 10; where X and Y together with the atoms to which they are attached can optionally form a cyclic heteroaliphatic group.

[0349] In some embodiments, each R, R 1 、R 2 、R 3 、R 4 、R 5 and R 6Independently selected from alkyl, alkenyl, alkynyl, heteroalkyl, heteroalkenyl, heteroalkynyl, haloalkyl, haloalkenyl, haloalkynyl, halohaloalkyl, halohaloalkenyl, halohaloalkynyl, aryl, heterocyclic group, heteroaryl, alkyl-aryl, alkenyl-aryl, alkynyl-aryl, alkyl-heterocyclic group, alkenyl-heterocyclic group, alkynyl-heterocyclic group, alkyl-heteroaryl, alkenyl-heteroaryl, alkynyl-heteroaryl, heteroalkyl-aryl, heteroalkenyl-aryl, heteroalkynyl-aryl, heteroalkyl-heterocyclic group, heteroalkenyl-heterocyclic group, heteroalkynyl-heterocyclic group, heteroalkyl-heteroaryl, heteroalkenyl-heteroaryl, heteroalkynyl-heteroaryl or any combination thereof. In certain disclosed embodiments, the ether may be further substituted with one or more substituents such as alkoxy, amide, amine, thioether, thiol, acyloxy, silyl, cycloaliphatic, aryl, aldehyde, ketone, ester, carboxylic acid, acyl, acyl halide, cyano, halogen, sulfonate, nitro, nitroso, quaternary amine, pyridyl (or pyridyl in which the nitrogen atom is functionalized with an aliphatic or aryl group), haloalkyl or any combination thereof.

[0350] In some embodiments, when X and Y together with the atoms to which they are attached form a cycloheteroaliphatic group, the organic solvent is a cyclic ether such as acetal, dioxane, dioxolane, etc. For example, when forming a ring, X and Y may each independently be a covalent bond or a polyvalent (e.g., divalent) form of an aliphatic group, alkyl, alkenyl, alkynyl, heteroaliphatic group, heteroalkyl, heteroalkenyl or heteroalkynyl. In some embodiments, when n = 1 and each R = H, X and Y together form a five-, six-, seven-, eight-, nine- or ten-membered ring. Exemplary ethers include but are not limited to 1,3-dioxolane or its derivatives. In other embodiments, when n = 2 and R = H, X and Y form a six-, seven-, eight-, nine- or ten-membered ring. Exemplary ethers include but are not limited to 1,4-dioxane or its derivatives. In still other embodiments, when n = 1 or n = 2, then R is aliphatic, haloaliphatic, halohaloaliphatic, heteroaliphatic, aromatic, aliphatic-aromatic, heteroaliphatic-aromatic or any combination thereof. Exemplary cyclic ethers include tetrahydrofuran, 2-methyltetrahydrofuran, 2-methyl-1,3-dioxolane and the like.

[0351] In other embodiments, when at least one of X or Y = aromatic, the organic solvent may be an aromatic ether. Exemplary aromatic ethers include anisole, diphenyl ether and the like.

[0352] In some embodiments, when at least one of X or Y = cycloaliphatic, the organic solvent may be a cycloalkyl ether. Exemplary cycloalkyl ethers include cyclopentyl methyl ether, cyclohexyl methyl ether and the like.

[0353] In other embodiments, when at least one of X or Y = -[C(R 4 )2-O] p -C(R 6 )3, the organic solvent can be a glycol-based ether. Exemplary glycol-based ethers include diethylene glycol diethyl ether, dipropylene glycol dimethyl ether, poly(ethylene glycol) dimethyl ether, etc., including methyl, ethyl, propyl, and butyl monoethers and diethers of ethylene glycol and the like.

[0354] In some examples, the organic solvent is a nitrile having the formula R-C≡N, where R is aliphatic, halogenated aliphatic, halogenated heteroaliphatic, heteroaliphatic, aromatic, aliphatic-aromatic, or heteroaliphatic-aromatic.

[0355] In certain embodiments, R may optionally be substituted with a hydroxyl group (e.g., in one example, R can be CH3-CH(OH)-CH2-, and the organic solvent will be CH3-CH(OH)-CH2-CN).

[0356] An example of the nitrile is acetonitrile, as described above.

[0357] In some embodiments, the organic solvent can include two or more of the organic solvents or types of organic solvents described herein. In some embodiments, water can be provided to replace the organic solvent, or water can be provided in addition to the organic solvent. Additive

[0358] In some embodiments, additives are used for the purpose of accelerating the reaction rate and enhancing the reaction selectivity. The additives can be selected from several different types of additives. For example, in some examples, the additives can be heterocyclic compounds, heteroaromatic compounds, halogen-substituted heteroaromatic compounds, heterocyclic aliphatic compounds, amines, fluoroamines, amino acids, organophosphorus compounds, oxidants, difluoride sources, ammonia, aldehydes, carbenes, or organic acids. In some examples, more than one additive can be used. In some embodiments, the additive can be a boron-containing Lewis acid or a Lewis adduct. Boron trifluoride (BF3) is an example of a Lewis acid that forms the acid-base adduct BF4-. In some examples, the additive may belong to two or more of the categories listed above.

[0359] In some embodiments, the additive is a heterocyclic aromatic compound. The term "aromatic" is defined as above. A heterocyclic aromatic compound is an aromatic compound that includes a 5-, 6-, or 7-membered ring (unless otherwise specified), which contains one, two, three, or four non-carbon heteroatoms (e.g., independently selected from the group consisting of nitrogen, oxygen, phosphorus, sulfur, or halogen). Exemplary heterocyclic aromatic compounds that can be used include, but are not limited to, picoline, pyridine, pyrrole, imidazole, thiophene, N-methylimidazole, N-methylpyrrolidone, benzimidazole, 2,2-bipyridine, dipicolinic acid, 2,6-dimethylpyridine, 4-N,N-dimethylaminopyridine, and azulene. In some instances, the heterocyclic aromatic compound can be methylated. In some instances, the heterocyclic aromatic compound can follow the Hückel 4n + 2 rule. In some instances, the additive is a halogen-substituted aromatic compound. A halogen-substituted aromatic compound is an aromatic compound that includes at least one halogen bonded to the aromatic ring. As used herein, halogen (halogen or halo) refers to F, Cl, Br, or I. Exemplary halogen-substituted aromatic compounds include, but are not limited to, 4-bromopyridine, chlorobenzene, 4-chlorotoluene, fluorobenzene, etc.

[0360] In some embodiments, the additive is a heterocyclic aliphatic compound. As used herein, "aliphatic" means a hydrocarbon group having at least one carbon atom to 50 carbon atoms (C 1-50 )), for example, one to 25 carbon atoms (C 1-25 ), or one to ten carbon atoms (C 1-10 ), and includes alkanes (or alkyls), alkenes (or alkenyls), alkynes (or alkynyls), including their cyclic forms, and further includes straight-chain and branched arrangements, as well as all stereoisomers and positional isomers. A heterocyclic aliphatic compound is an aliphatic compound that includes a 5-, 6-, or 7-membered ring (unless otherwise specified), which contains one, two, three, or four non-carbon heteroatoms (e.g., independently selected from the group consisting of nitrogen, oxygen, phosphorus, sulfur, or halogen). Exemplary heterocyclic aliphatic compounds include pyrrolidine, piperidine, etc.

[0361] In some embodiments, the additive is an amine having the formula NR 1 R 2 R 3 where: R 1 、R 2 and R 3 are each independently selected from hydrogen, hydroxy, aliphatic, haloaliphatic, halometaaliphatic, metaaliphatic, aromatic, aliphatic-aromatic, metaaliphatic-aromatic, or any combination thereof; where R 1 and R2 optionally form a cycloheteroaliphatic group together with the atoms to which they are attached; and wherein R 1 , R 2 and R 3 optionally form a cycloheteroaliphatic group together with the atoms to which they are attached.

[0362] In some embodiments, R 1 , R 2 and R 3 are each independently selected from alkyl, alkenyl, alkynyl, heteroalkyl, heteroalkenyl, heteroalkynyl, haloalkyl, haloalkenyl, haloalkynyl, halohaloalkyl, halohaloalkenyl, halohaloalkynyl, aryl, heterocyclic group, heteroaryl, alkyl-aryl, alkenyl-aryl, alkynyl-aryl, alkyl-heterocyclic group, alkenyl-heterocyclic group, alkynyl-heterocyclic group, alkyl-heteroaryl, alkenyl-heteroaryl, alkynyl-heteroaryl, heteroalkyl-aryl, heteroalkenyl-aryl, heteroalkynyl-aryl, heteroalkyl-heterocyclic group, heteroalkenyl-heterocyclic group, heteroalkynyl-heterocyclic group, heteroalkyl-heteroaryl, heteroalkenyl-heteroaryl, heteroalkynyl-heteroaryl or any combination thereof. In certain disclosed embodiments, the amine may be further substituted with one or more substituents such as alkoxy, amide, amine, hydroxy, thioether, thiol, acyloxy, silyl, cycloaliphatic, aryl, aldehyde, ketone, ester, carboxylic acid, acyl, acyl halide, cyano, halogen, sulfonate, nitro, nitroso, quaternary amine, pyridyl (or pyridyl in which the nitrogen atom is functionalized with an aliphatic or aryl group), haloalkylated or any combination thereof.

[0363] In some embodiments, when at least one of R 1 , R 2 and R 3 is aliphatic, haloaliphatic, halohaloaliphatic or heteroaliphatic, the additive is an alkylamine. The alkylamine may include dialkylamine, trialkylamine and their derivatives. Exemplary alkylamines include methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, isopropylamine, 1,2-ethylenediamine, dimethylisopropylamine, N-ethyldiisopropylamine, trimethylamine, dimethylamine, methylamine, triethylamine, tert-butylamine and the like.

[0364] In other embodiments, when at least one of R 1 , R 2 and R 3 includes a hydroxy group, the additive is an alkanolamine. In one example, R 1 , R 2 and R 3At least one of them is an aliphatic group substituted by one or more hydroxyl groups. Exemplary alkanolamines include 2-(dimethylamino)ethanol, 2-(diethylamino)ethanol, 2-(dipropylamino)ethanol, 2-(dibutylamino)ethanol, N-ethyldiethanolamine, N-tert-butyldiethanolamine, and the like.

[0365] In some embodiments, when R 1 and R 2 together with the atoms to which they are attached form a cycloheteroaliphatic, the additive can be a cyclic amine. Exemplary cyclic amines include piperidine, N-alkylpiperidines (e.g., N-methylpiperidine, N-propylpiperidine, etc.), pyrrolidine, N-alkylpyrrolidines (e.g., N-methylpyrrolidine, N-propylpyrrolidine, etc.), morpholine, N-alkylmorpholines (e.g., N-methylmorpholine, N-propylmorpholine, etc.), piperazine, N-alkylpiperazines, N,N-dialkylpiperazines (e.g., 1,4-dimethylpiperazine), and the like.

[0366] In other embodiments, when R 1 , R 2 and R 3 at least one of them includes an aromatic group, the additive is an aromatic amine. In some embodiments, R 1 , R 2 and R 3 at least one of them is aromatic, aliphatic-aromatic, or heteroaliphatic-aromatic. In other embodiments, R 1 and R 2 include an aromatic group. In still other embodiments, R 1 and R 2 and optionally R 3 together with the atoms to which they are attached form an aromatic cycloheteroaliphatic. Exemplary aromatic amines include aniline, aniline derivatives, histamine, pyrrole, pyridine, imidazole, pyrimidine, and their derivatives.

[0367] In some embodiments, the additive can include amines selected from the group consisting of methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, isopropylamine, 1,2-ethylenediamine, aniline (and aniline derivatives such as N,N-dimethylaniline), N-ethyldiisopropylamine, tert-butylamine, and combinations thereof.

[0368] In some embodiments, the additive can include fluoroamines. Fluoroamines are amines having one or more fluorinated substituents. Exemplary fluoroamines that can be used include, but are not limited to, 4-trifluoromethylaniline.

[0369] In some embodiments, the additive can be a nitrogenous analog of carbonic acid having the formula R 1 N-C(NR 2 )-NR 3。Exemplary additives may include, but are not limited to, guanidine or its derivatives.

[0370] In some embodiments, the additive may be a relatively low molecular weight amine, e.g., having a molecular weight of less than 200 g / mol or 100 g / mol in certain embodiments. Higher molecular weight amines may be used in some embodiments, including those having long chains or heterocyclic compounds with aromatic rings.

[0371] In some embodiments, the additive may include amino acids. The amino acid may have the formula R-CH(NR′2)-COOH, where: each R and R′ is independently a hydroxyl group, aliphatic, halogenated aliphatic, halogenated heteroaliphatic, heteroaliphatic, aromatic, aliphatic-aromatic, heteroaliphatic-aromatic, or any combination thereof.

[0372] Exemplary amino acids that may be used include, but are not limited to, histidine, alanine, and their derivatives.

[0373] In some embodiments, the additive may include organic phosphorus compounds. The organic phosphorus compounds may be phosphate ester, phosphate amide, phosphonic acid, phosphinic acid, phosphonate, phosphinate, phosphine oxide, phosphine imide, or phosphonium salts. Exemplary organic phosphorus compounds include phosphoric acid and trialkyl phosphates. In some instances, the organic phosphorus compound is phosphazene. Phosphazene is an organic phosphorus compound containing phosphorus(V) with a double bond between P and N. The phosphazene may have the formula RN=P(NR2)3 (where R and R2 are each independently selected from a hydroxyl group, aliphatic, halogenated aliphatic, halogenated heteroaliphatic, heteroaliphatic, aromatic, aliphatic-aromatic, heteroaliphatic-aromatic, or any combination thereof). In some instances, the phosphazene has the formula [X2PN] n (where X is a halogen root, alkoxide, or amide). Other types of phosphazenes may be used as needed.

[0374] In some embodiments, the additive includes an oxidizing agent. As used herein, an oxidizing agent is a material capable of oxidizing another substance (e.g., accepting electrons from it). Exemplary oxidizing agents that may be used include, but are not limited to, hydrogen peroxide, sodium hypochlorite, tetramethylammonium hydroxide, and combinations thereof.

[0375] In some embodiments, the additive includes a difluoride source. The difluoride source is a material that contains or generates difluoride (HF2- ) materials. Exemplary difluoride sources that can be used include, but are not limited to, ammonium fluoride, aqueous HF, gaseous HF, buffered oxide etch mixtures (e.g., mixtures of HF with a buffer such as ammonium fluoride), and pyridine hydrofluoride. In some embodiments, the difluoride source (or one or more other additives listed herein) can react before or after being delivered to the reaction chamber to form HF2 - .

[0376] In certain embodiments, the additive can act as a proton acceptor and facilitate the formation of HF2 - . In some such instances, HF2 - can actively etch one or more materials on the substrate, such as oxide materials or another material.

[0377] In some embodiments, the additive includes an aldehyde having the formula X-[C(O)]-H, where: X is independently selected from hydrogen, -R 1 , -C(R 2 )3 or -[C(R 3 )2] m -C(O)H, where each R 1 , R 2 and R 3 is independently selected from hydrogen, aliphatic, haloaliphatic, haloheteroaliphatic, heteroaliphatic, aromatic, aliphatic-aromatic, heteroa liphatic-aromatic, or any combination thereof, and m is an integer from 0 to 10.

[0378] In some embodiments, R 1 , R 2 and R 3 are each independently an alkyl, alkenyl, alkynyl, heteroalkyl, heteroalkenyl, heteroalkynyl, haloalkyl, haloalkenyl, haloalkynyl, haloheteroalkyl, haloheteroalkenyl, haloheteroalkynyl, aryl, heterocyclic, heteroaryl, alkyl-aryl, alkenyl-aryl, alkynyl-aryl, alkyl-heterocyclic, alkenyl-heterocyclic, alkynyl-heterocyclic, alkyl-heteroaryl, alkenyl-heteroaryl, alkynyl-heteroaryl, heteroalkyl-aryl, heteroalkenyl-aryl, heteroalkynyl-aryl, heteroalkyl-heterocyclic, heteroalkenyl-heterocyclic, heteroalkynyl-heterocyclic, heteroalkyl-heteroaryl, heteroalkenyl-heteroaryl, heteroalkynyl-heteroaryl, or any combination thereof. In certain disclosed embodiments, the aldehyde or ketone can be further substituted with one or more substituents such as aldehyde (-C(O)H), oxo (=O), alkoxy, amide, amine, hydroxyl, thioether, thiol, acyloxy, silyl, cycloaliphatic, aryl, aldehyde, ketone, ester, carboxylic acid, acyl, acyl halide, cyano, halogen, sulfonate, nitro, nitroso, quaternary amine, pyridyl (or pyridyl in which the nitrogen atom is functionalized with an aliphatic or aryl group), haloalkyl, or any combination thereof.

[0379] In some embodiments, when X = aromatic, the additive can be an aromatic aldehyde. Exemplary aromatic aldehydes include benzaldehyde, 1-naphthaldehyde, phthalaldehyde, and the like.

[0380] In other embodiments, when X = aliphatic, the additive can be an aliphatic aldehyde. Exemplary aliphatic aldehydes include acetaldehyde, propionaldehyde, butyraldehyde, isovaleraldehyde, and the like.

[0381] In still other embodiments, when X = -[C(R 3 )2] m -C(O)H and m is from 0 to 10 or when X is an aliphatic or heteroaliphatic substituted with -C(O)H, the additive can be a dialdehyde. Exemplary dialdehydes include glyoxal, phthalaldehyde, glutaraldehyde, malonaldehyde, succinaldehyde, and the like.

[0382] In some instances, the aldehyde used as an additive can be selected from the group consisting of acrolein, acetaldehyde, formaldehyde, benzaldehyde, propionaldehyde, butyraldehyde, cinnamaldehyde, vanillin, and tolualdehyde. In these or other examples, the aldehyde used as an additive can be selected from the aldehydes discussed in this section and the aldehydes discussed in the organic solvents section.

[0383] In some embodiments, the additive includes carbenes. The carbene can have the formula X-(C:)-Y, where: X and Y can each independently be selected from H, halogen, -[C(R 1 )2] m -C(R 2 )3, -C(O)-R 1 or -C(=NR 1 )-R 2 , -NR 1 R 2 , -OR 2 , -SR 2 or -C(R 2 )3, where R 1 and R 2 are each independently selected from hydrogen, hydroxy, aliphatic, haloaliphatic, haloheteroaliphatic, heteroaliphatic, aromatic, aliphatic-aromatic, heteroaliphatic-aromatic, or any combination thereof, where m is an integer from 0 to 10; where R 1 and R 2 together with the atoms to which they are attached can optionally form a cyclic heteroaliphatic group; and where X and Y together with the atoms to which they are attached can optionally form a cycloaliphatic or cyclic heteroaliphatic group.

[0384] In addition, the additive can be one having the formula R 1 -C+ (R)-R 2 of the carbocation, where R, R 1 and R 2 are each independently selected from hydrogen, aliphatic, haloaliphatic, haloheteroaliphatic, heteroaliphatic, aromatic, aliphatic-aromatic, heteroaliphatic-aromatic, or any combination thereof.

[0385] In some embodiments, each R, R 1 and R 2 are independently selected from alkyl, alkenyl, alkynyl, heteroalkyl, heteroalkenyl, heteroalkynyl, haloalkyl, haloalkenyl, haloalkynyl, halohaloalkyl, halohaloalkenyl, halohaloalkynyl, aryl, heterocyclic, heteroaryl, alkyl-aryl, alkenyl-aryl, alkynyl-aryl, alkyl-heterocyclic, alkenyl-heterocyclic, alkynyl-heterocyclic, alkyl-heteroaryl, alkenyl-heteroaryl, alkynyl-heteroaryl, heteroalkyl-aryl, heteroalkenyl-aryl, heteroalkynyl-aryl, heteroalkyl-heterocyclic, heteroalkenyl-heterocyclic, heteroalkynyl-heterocyclic, heteroalkyl-heteroaryl, heteroalkenyl-heteroaryl, heteroalkynyl-heteroaryl, or any combination thereof. In certain disclosed embodiments, the carbene may be further substituted with one or more substituents, such as alkoxy, amide, amine, hydroxy, thioether, thiol, acyloxy, silyl, cycloaliphatic, aryl, aldehyde, ketone, ester, carboxylic acid, acyl, acyl halide, cyano, halogen, sulfonate, nitro, nitroso, quaternary amine, pyridyl (or pyridyl in which the nitrogen atom is functionalized with an aliphatic or aryl group), haloalkyl, or any combination thereof. In any embodiment of the carbene, R 1 and R 2 may each be independently selected.

[0386] In some embodiments, when at least one of X or Y is a halogen, the additive may be a halo carbene. Exemplary non-limiting halo carbenes include dihalo carbenes, such as dichloro carbene, difluoro carbene, and the like.

[0387] In some embodiments, when X = Y = -NR 1 R 2 , the additive may be a diamino carbene. In one example, R 1 and R 2 are each independently aliphatic. Exemplary diamino carbenes include bis(diisopropylamino) carbene and the like.

[0388] In other embodiments, when at least one of X or Y = -NR 1 R 2 and the R 1 within X or Y and R 2When both of them and the nitrogen atoms to which they are attached form a cycloheteroaliphatic group, the additive can be a cyclic diaminocarbene. Exemplary cyclic diaminocarbenes include bis(N-piperidyl)carbene, bis(N-pyrrolidyl)carbene and the like.

[0389] In one example, when X = Y = -NR 1 R 2 and the R 1 group from X and the R 2 group from Y, together with the nitrogen atoms to which they are attached, form a cycloheteroaliphatic group, the additive is an N-heterocyclic carbene. Exemplary N-heterocyclic carbenes include imidazol-2-ylidene (e.g., 1,3-dimesitylimidazol-2-ylidene, 1,3-dimesityl-4,5-dichloroimidazol-2-ylidene, 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene, 1,3-di-tert-butylimidazol-2-ylidene, etc.), imidazolidin-2-ylidene (e.g., 1,3-bis(2,6-diisopropylphenyl)imidazolidin-2-ylidene), triazol-5-ylidene (e.g., 1,3,4-triphenyl-4,5-dihydro-1H-1,2,4-triazol-5-ylidene) and the like.

[0390] In some embodiments, when X = -NR 1 R 2 and Y = -SR 2 and the R 1 group from X and the R 2 group from Y, together with the nitrogen atoms to which they are attached, form a cycloheteroaliphatic group, the additive is a cyclic thioalkylaminocarbene. Exemplary cyclic thioalkylaminocarbenes include thiazol-2-ylidene (e.g., 3-(2,6-diisopropylphenyl)thiazol-2-ylidene and the like).

[0391] In some embodiments, when X = -NR 1 R 2 and Y = -C(R 2 )3 and the R 1 group from X and the R 2When the group together with the atoms to which it is attached forms a cycloheteroaliphatic group, the additive is an exemplary cyclic alkyl carbene. Exemplary cyclic alkyl carbenes include pyrrolidine-2-carbenes (e.g., 1,3,3,5,5-pentamethyl-pyrrolidine-2-carbenes, etc.) and piperidine-2-carbenes (e.g., 1,3,3,6,6-pentamethyl-piperidine-2-carbenes and the like).

[0392] Further exemplary carbenes and their derivatives include compounds having a thiazole-2-ylidene moiety, a dihydroimidazol-2-ylidene moiety, an imidazol-2-ylidene moiety, a triazol-5-ylidene moiety, or a cyclopropenylidene moiety. Other carbenes and carbene analogs include aminothiocarbenes, aminooxycarbenes, diamino carbenes, heteroamino carbenes, 1,3-dithiolium carbenes, mesoionic carbenes (such as imidazolin-4-ylidene compounds, 1,2,3-triazol-4-ylidene compounds, pyrazolin-4-ylidene compounds, tetrazol-5-ylidene compounds, isoxazol-4-ylidene compounds, thiazol-5-ylidene compounds, etc.), cycloalkylamino carbenes, boranylidene compounds, silylene compounds, stannylene compounds, nitrene compounds, phosphinidene compounds, foiled carbene compounds, etc. Further exemplary carbenes include dimethylimidazol-2-ylidene, 1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene, (phosphino)(trifluoromethyl)carbene, bis(diisopropylamino)carbene, bis(diisopropylamino)cyclopropenylidene, 1,3-dimesityl-4,5-dichloroimidazol-2-ylidene, 1,3-diadamantylimidazol-2-ylidene, 1,3,4,5-tetramethylimidazol-2-ylidene, 1,3-dimesitylimidazol-2-ylidene, 1,3-dimesitylimidazol-2-ylidene, 1,3,5-triphenyltriazol-5-ylidene, bis(diisopropylamino)cyclopropenylidene, bis(9-anthryl)carbene, norborneN-7-ylidene, dihydroimidazol-2-ylidene, methylidenecarbene, etc.

[0393] In some embodiments, the additive includes an organic acid. The organic acid may have the formula R-CO2H, where R is selected from hydrogen, aliphatic, haloaliphatic, haloheteroaliphatic, heteroaliphatic, aromatic, aliphatic-aromatic, heteroaliphatic-aromatic, or any combination thereof. In certain embodiments, R is an alkyl, alkenyl, alkynyl, heteroalkyl, heteroalkenyl, heteroalkynyl, haloalkyl, haloalkenyl, haloalkynyl, haloheteroalkyl, haloheteroalkenyl, haloheteroalkynyl, aryl, heteroaryl, alkyl-aryl, alkenyl-aryl, alkynyl-heteroaryl, alkyl-heteroaryl, alkenyl-heteroaryl, alkynyl-heteroaryl, heteroalkyl-aryl, heteroalkenyl-aryl, heteroalkynyl-aryl, heteroalkyl-heteroaryl, heteroalkenyl-heteroaryl, heteroalkynyl-heteroaryl, or any combination thereof. In certain disclosed embodiments, R may be further substituted with one or more substituents, such as an alkoxy, amide, amine, thioether, hydroxyl, thiol, acyloxy, silyl, cycloaliphatic, aryl, aldehyde, ketone, ester, carboxylic acid, acyl, acyl halide, cyano, halogen, sulfonate, nitro, nitroso, quaternary amine, pyridyl (or pyridyl where the nitrogen atom is functionalized with an aliphatic or aryl group), alkylhalide, or any combination thereof. In certain implementations, the organic acid may be selected from formic acid and acetic acid. Carrier gas

[0394] The carrier gas may be an inert gas, a noble gas, or other gas as described herein. In some examples, the carrier gas is a noble gas. In certain embodiments, the carrier gas may be selected from the group consisting of N2, He, Ne, Ar, Kr, and Xe. In some such embodiments, the carrier gas may be selected from the group consisting of N2, He, and Ar. Pretreatment operation

[0395] One or more pretreatment operations may be performed to provide at least one of a passivated surface or a pristine surface. In one example, the pretreatment provides a passivated surface on the substrate prior to deposition. In another example, the pretreatment may remove contaminants (e.g., oxygen, carbon, fluorine, and the like) located on the substrate surface, where such contaminants may be present on the surface after pre-cleaning but prior to deposition. In other non-limiting embodiments, a pretreatment may be employed between deposition cycles for providing a stack. During the pretreatment, an optional etching step (e.g., any etching conditions described herein) may be performed.

[0396] Typically, the pre-treatment is carried out in the presence of a hydrogen-containing reagent to provide a hydrogen-passivated surface. In one example, the pre-treatment of a silicon substrate generally includes a baking step of hydrogen soak (e.g., 10% H2 in an inert gas such as argon). The temperature range of the pre-treatment can be from about 300 °C to greater than about 700 °C. During the cleaning and passivation of the substrate, a hydrogen environment of less than about 10 Torr is generally applied on the substrate surface. In other embodiments, a thermal soak (e.g., greater than about 700 °C as described herein) can be carried out at a higher pressure (e.g., greater than 10 Torr).

[0397] Here, any hydrogen-containing reagent can be adjusted or replaced to provide a deuterium-containing reagent. Without wishing to be bound by theory, one benefit of deuterium is that the Si-D bond (as presented on the deuterated surface) can be more stable than the Si-H bond (as presented on the hydrogenated surface). Thus, in some examples, if a deuterium-containing reagent (including deuterium gas) is used during the pre-treatment operation, the presence of such Si-D bonds can provide a more stable surface. Thus, in any embodiment herein, the hydrogen soak gas can be supplemented with a deuterium soak gas (e.g., a combination of 10% H2 and D2 in an inert gas such as argon), or the hydrogen soak gas can be replaced with a deuterium soak gas (e.g., 10% D2 in an inert gas such as argon), or the hydrogen soak gas can be replaced with a hydrogen deuteride soak gas (e.g., 10% HD in an inert gas such as argon).

[0398] In one example, a hydrogen-containing or deuterium-containing soak gas (e.g., H2, D2, HD, or others) can be used in the presence of high temperature to radiatively heat the substrate for temporary heating or resistively heat the substrate through a pedestal. Such temperatures can include greater than about 700 °C, greater than about 750 °C, or greater than about 775 °C. The radiative heating can include using a heat lamp to heat, an LED array, or any of those described herein.

[0399] Alternatively, a hydrogen-containing or deuterium-containing soak gas (e.g., H2, D2, HD, or others) can be used with a plasma (e.g., an in-situ plasma generated in the chamber or a remote plasma delivered to the chamber). The plasma conditions can be any of those described herein. In one example, in the presence of a plasma, the temperature of the pre-treatment can include from about 250 °C to 650 °C. For example, the temperature can be increased by using a heat lamp to heat, resistive heating (through a pedestal), LED-based heating for temporary heating, and radiative heating for rapid heating of the wafer.

[0400] The pretreatment may include using any type of activated hydrogen or activated deuterium. In one example, a plasma is used with a hydrogen-containing reagent (e.g., H2, a hydrogen-containing silane such as SiH4) to provide activated hydrogen. In another example, a plasma is used with a deuterium-containing reagent (e.g., D2, HD, a deuterium-containing silane such as SiD4) to provide activated deuterium. In the case of using a plasma, an inert gas (e.g., He, Ar, N2, etc.) may or may not be used. The plasma may include any of those described herein, including a remote plasma. After pretreatment, the pretreated surface may be maintained by controlling the environment or by storing the substrate under vacuum.

[0401] The hydrogen-containing reagent or deuterium-containing reagent may be provided by using a catalyst. Non-limiting catalysts that can be used to regenerate or produce hydrogen or deuterium may include platinum (Pt), iridium (Ir), palladium (Pd), rhodium (Rh), nickel (Ni), and combinations thereof.

[0402] Activated hydrogen or deuterium may be provided by using a plasma and any hydrogen-containing or deuterium-containing reactant. Any activated hydrogen process may be used, such as by employing a catalytic hydrogen process to generate hydrogen species in a chamber. In one example, atomic hydrogen may be formed in a plasma, and then the atomic hydrogen may react with a catalyst to provide a lower energy hydrogen species. As used herein, "lower energy hydrogen species" may include any species containing hydrogen atoms having energy lower than unreacted atomic hydrogen. Non-limiting sources of atomic hydrogen may include molecular hydrogen. Activated hydrogen may be formed in the presence of a reducing agent such as hydrides, silanes (e.g., SiH4), boranes, hydrazine, diborane, germane, phosphates, trimethylaluminum (TMA or AlMe3), which can be used to scavenge fluorine), and the like. Similarly, by substituting deuterium for hydrogen, activated deuterium may be formed.

[0403] In one embodiment, the pretreatment includes using hydrogen (H2), deuterium (D2), deuterated hydrogen (HD), or a combination thereof in the presence of a plasma (including a remote plasma or an in-situ plasma). In some embodiments, a remote plasma is employed. Optionally, H2, D2, HD, or a combination thereof is used in the presence of an inert gas, helium, argon, and the like. In use, radicals generated by the plasma, metastable species generated by the plasma, or a combination thereof clean the surface of the substrate.

[0404] In another embodiment, a minimal amount of a reducing agent (e.g., any of those herein, such as silane, SiH4, and the like) can be introduced downstream of a plasma source (e.g., downstream of a remote plasma source). The reducing agent (e.g., SiH4) can be used alone or in combination with H2, D2, HD, or a combination thereof. A large amount of SiH4 may result in deposition, while a minimal amount of SiH4 may result in surface etching. In addition, SiH4-based radicals generated in this manner can be used in combination with hydrogen- or deuterium-containing radicals to clean the surface. Non-limiting flow rates of the reducing agent include, for example, less than 1 sccm, less than 2 sccm, or about 0.01 - 2 sccm (e.g., for SiH4 for each 300 mm wafer). Deposition operation

[0405] A deposition operation can be performed to provide a heterolayer (e.g., a heteroepitaxial layer) within a stack. In certain embodiments, to facilitate low-temperature deposition conditions, a plasma can be used to provide epitaxial growth of a semiconductor layer or a sacrificial layer. In some embodiments, low-temperature processing conditions are required to minimize atomic diffusion between heterolayers. To enhance growth even at low temperatures, a plasma can be used to provide ground-state or excited radicals, metastable species (e.g., higher-energy long-lived states), charged species (ions), or other high-energy species, which in turn can provide activated precursor species for deposition.

[0406] In some embodiments, plasma-based epitaxy includes using a remote plasma source separate from the epitaxy chamber or using an in-situ plasma to generate a plasma within the epitaxy chamber. The plasma can be used with or without an ion filter.

[0407] As further described herein, a plasma can be used to provide various types of activated species. It should be noted that in some embodiments, a reactive plasma can be substantially free of components that react with silicon, with germanium, or with both silicon and germanium. In one example, a reactive plasma can contain only hydrogen (e.g., H* or H2), deuterium (e.g., D* or D2), deuterated hydrogen (HD), an inert gas (e.g., He, Ar, He*, Ar*, etc.), or any combination thereof. In another example, a reactive plasma does not contain nitrogen-containing, halogen-containing, or oxygen-containing species. In one embodiment, a plasma can be used to activate a precursor, where the activated precursor species can be delivered to the epitaxy chamber or formed within the epitaxy chamber. Such processes can be considered direct activation of the precursor.

[0408] Indirect activation (e.g., without an ion filter) may also be employed. In one embodiment, a plasma may be used to activate an inert gas (e.g., He or Ar) upstream of the precursor, and then the activated inert species may combine with the precursor in the epitaxial chamber. In another embodiment, a plasma may be used to activate hydrogen (H2) upstream of the precursor, and then the activated hydrogen species may combine with the precursor in the epitaxial chamber. In yet another embodiment, a plasma may be used to activate deuterium (D2) or deuterated hydrogen (HD) upstream of the precursor, and then the activated deuterium species may combine with the precursor in the epitaxial chamber. Activation by the plasma may occur within the excitation chamber (upstream of the deposition chamber) or within the deposition chamber (e.g., the epitaxial chamber).

[0409] Here, any hydrogen-containing reagent may be adjusted or replaced to provide a deuterium-containing reagent. Without wishing to be bound by theory, in some non-limiting examples, D* radicals may recombine, which is less than H* radicals or H*-like radicals. Without wishing to be bound by theory, in some non-limiting examples, compared to H* radicals, D* radicals may provide more of certain desired high-energy species in the plasma. To some extent, such results may be due to the larger collision cross-section of D atoms compared to H atoms. Additional other benefits may be observed by providing a deuterium-containing reagent during deposition. Thus, in any embodiment herein, a hydrogen-containing reagent (including a hydrogen-containing gas) may be supplemented with a deuterium-containing reagent or replaced with a deuterium-containing reagent during deposition.

[0410] Deposition of the semiconductor layer or sacrificial layer may include any useful method, which may be plasma-enhanced. Such methods may include atomic layer deposition (ALD), plasma-enhanced ALD (PEALD), chemical vapor deposition (CVD), plasma-enhanced CVD (PECVD), or remote plasma CVD (RPCVD).

[0411] The plasma can be generated in any useful manner. The plasma source can be in-situ or remote (e.g., located upstream of the processing chamber where the substrate is located). Examples of in-situ plasma sources include capacitively coupled plasma (CCP) sources, inductively coupled plasma (ICP) sources, transformer coupled plasma (TCP) sources, electron cyclotron resonance (ECR) plasma sources (e.g., where a magnetic field is used to provide an alternating electric field that increases the kinetic energy of electrons within the gas and ionizes the plasma), surface wave plasma (SWP) sources (e.g., where a circularly polarized high-gain antenna or a linearly polarized array is used to provide surface wave plasma in the microwave and millimeter wave bands, e.g., achieved by using a radial line slot antenna), microwave plasma (MWP) sources, ultraviolet light (UV) assisted plasma sources, low energy plasma (LEP) sources, low temperature plasma (LTP) sources, or the like. Examples of remote plasma sources include capacitively coupled plasma (CCP) sources, parallel plate CCP sources (e.g., where plasma species from the parallel plates are transported through an ion filter and then the filtered species are delivered to the substrate), ICP sources, TCP sources, surface wave plasma (SWP) sources, hollow cathode plasma sources, microwave plasma (MWP) sources, low energy plasma (LEP) sources, low temperature plasma (LTP) sources, or the like. Any of these can be used with or without ion filtering.

[0412] The plasma can be ignited with a power per substrate area between about 0.2122 W / cm 2 and about 2.122 W / cm 2 . For example, the power can be in the range of about 150 W to 6000 W, or about 600 W to 6000 W. A variety of frequencies can be used to generate the plasma, which depends, for example, specifically on the type of plasma source. For example, the frequency can be in the range of about 60 kHz to 100 MHz. In some implementations, the frequency can be in the microwave range, e.g., 700 MHz to 1000 GHz. Other additional non-limiting frequencies can include about 60 kHz to 60 MHz or about 100 MHz to microwave (e.g., 1 GHz to 1000 GHz). In some embodiments, the frequencies include about 60 kHz, 100 kHz, 200 kHz, 400 kHz, 1200 kHz, 2 MHz, 13.5 MHz, 27 MHz, 40 MHz, or 60 MHz. In other embodiments, the plasma source can be a low energy plasma (LEP) source (e.g., a low energy in-situ plasma source). In certain non-limiting embodiments, the LEP source provides a plasma having an energy of about 0.1 eV to 20 eV. In other embodiments, the plasma has a high density at the wafer surface, e.g., at least about 10 10 cm -3 in density.

[0413] In any implementation of the present disclosure, the high-energy material can be configured to have any useful density. In certain embodiments, the high-energy material is characterized by a density of at least about 10 8 cm -3 、10 9 cm -3 、10 10 cm -3 、10 11 cm -3 、or 10 12 cm -3 or greater at the substrate surface. In some embodiments, the high-energy material (e.g., free radicals, metastable species, and the like) is characterized by a density of about 10 8 cm -3 to 10 13 cm -3 .

[0414] Deposition can include any useful range of process parameters. Such parameters can include a pedestal temperature range (e.g., 250°C - 650°C), a chamber pressure range (e.g., in the range of about 0.1 Torr - 10 Torr, optionally in the range of about 0.5 Torr - 3 Torr), a precursor flow rate (e.g., for a 300 mm wafer, 1 - 100 sccm of SiH4, 1 - 25 sccm of GeH4 (where H2 can be about 10%), or the like), an inert gas / carrier gas flow rate (e.g., for a 300 mm wafer, 100 - 2000 sccm), a plasma power (e.g., for a 300 mm wafer, 500 W - 6 kW), a plasma frequency (e.g., about 13.56 MHz, in the range of about 400 - 1000 kHz, or any other suitable plasma frequency), a process gas composition (e.g., 2 - 100% H2 in helium or argon, gas flow rate about 2 - 25 slm), a deposition rate (e.g., in the range of about 10 Å per minute - 500 Å per minute), and the like.

[0415] As described above, deposition can occur by flowing a precursor into the chamber where the substrate is located. For example, the precursor can be provided at any useful flow rate. In one embodiment, the flow rate of the precursor can be greater than 1 sccm, or greater than 10 sccm, or greater than 50 sccm, or greater than 100 sccm, or greater than 200 sccm; or about 20 sccm to 300 sccm. In one example, SiH4 can have a flow rate in the range of about 1 - 100 sccm. In another example, GeH4 can have a flow rate in the range of about 1 sccm - 25 sccm. As described above, a carrier gas can be used with the precursor. The carrier gas can have any useful flow rate, e.g., about 100 sccm to 2000 sccm. The precursor to carrier gas in the deposition chamber can have a volume ratio between 2000:1 and 1:1.

[0416] As described herein, alternating layers of a semiconductor layer (e.g., a Si layer) and a sacrificial layer (e.g., a SiGe layer) may be deposited. The deposition may occur at a rate of at least about 10 nanometers per minute (nm / min) or at least about 30 nm / min, such as at 10 nm / min, 30 nm / min, 60 nm / min, or the like; or at a rate of about 10 nm / min to 60 nm / min; or at a rate of about 3 nm / min to 15 nm / min. In some implementations, the chamber pressure may be maintained in the range of about 0.5 Torr - 3 Torr.

[0417] In some instances, the deposition may include introducing dopants. Non-limiting dopants include Group IV atoms such as carbon (C), germanium (Ge), tin (Sn), and the like; Group III atoms such as boron (B), aluminum (Al), gallium (Ga), indium (In), and the like; Group V atoms such as nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb), and the like. In some instances, a dopant such as carbon or boron may be used in the SiGe layer or at the interface between the two layers to prevent Ge from diffusing from the SiGe layer into the Si layer. The dopants may be introduced by using one or more dopant precursors (such as any of those described herein).

[0418] The deposition may also include depositing an interface layer. Such an interface layer between the semiconductor layer and the sacrificial layer may prevent the diffusion of specific atoms (e.g., dopant atoms, such as Ge from the SiGe layer into the Si layer). In other embodiments, such an interface layer may be used to confine the dopant concentration profile, thus enhancing the dopant concentration-dependent etch selectivity of the etch chemistry. In some embodiments, the interface layer may be epitaxial deposition (e.g., by using epitaxy).

[0419] Prior to deposition, the substrate may optionally be heated or treated with plasma.

[0420] During deposition, any exposed surface may optionally be heated or treated with plasma. In one embodiment, the interface between the first layer and the second layer may be treated. In one instance, the substrate may be exposed to plasma (such as any of those described herein), thus providing a preparatory surface between the first and second semiconductor layers. In another instance, the deposition may include flowing a first precursor into the reaction chamber and towards the substrate in the presence of high-energy species (such as radicals, metastable species, and the like) to form a first semiconductor layer; exposing the first semiconductor layer to plasma; and then flowing a second precursor and an optional third precursor into the reaction chamber and towards the substrate in the presence of high-energy species (such as radicals, metastable species, and the like) to form a second semiconductor layer.

[0421] In one example, the deposition can include a single cycle of delivering a silicon-containing precursor; optionally purging the chamber; delivering a germanium-containing precursor; optionally purging the chamber. Additionally, the deposition can include repeating the cycle any number of times to obtain a stack of a desired height. During deposition, the temperature can be maintained at about 250 °C to 750 °C, or about 250 °C to 600 °C. In some implementations, deposition at a relatively low temperature (e.g., below about 650 °C) can allow for a higher germanium concentration in the deposited SiGe layer. When etching the sacrificial SiGe layer, the higher germanium concentration can allow for better etch selectivity. Plasma can be provided during any part of this cycle, such as during a delivery operation. Non-limiting RF power for the plasma can be about 300 W to 600 W, about 600 W to 800 W, or about 2 kW to 3 kW (e.g., in the example of a remote plasma).

[0422] In addition to the precursors, the environment adjacent to the workpiece (e.g., substrate) can include one or more energetic species, radical species, metastable species, ions, or neutral species. An in-situ plasma or a remote plasma can include the one or more energetic species, radical species, metastable species, ions, or neutral species, where the one or more energetic species, radical species, metastable species, ions, or neutral species can interact with the precursors to activate the precursors. In some embodiments, the one or more radical species are preferably in a fairly low energy state. Examples of such radical species include hydrogen atom radicals. In some embodiments, as used herein, a fairly low energy state can include all, or substantially all, or most of the hydrogen atom radicals being in the ground state, e.g., at least about 90% or 95% of the hydrogen atom radicals adjacent to the workpiece being in the ground state. In certain embodiments, a source gas is provided in a carrier gas such as helium or argon. In various embodiments, hydrogen gas can be the source gas. As an example, hydrogen gas can be provided in a helium carrier at a hydrogen concentration of about 4 - 25%. The pressure, the proportion of the carrier gas (e.g., helium), and other process conditions are selected such that hydrogen atoms contact the substrate in the form of radicals in a low energy state without recombination.

[0423] For any use of the present disclosure, energetic species can be generated from any useful source gas. In some implementations, a plasma can be ignited using the source gas. The source gas can include a hydrogen-containing gas, a deuterium-containing gas, an oxygen-containing gas, a nitrogen-containing gas, or an inert gas such as a helium-containing gas, an argon-containing gas, or other inert gas, and combinations thereof. In some embodiments, the source gas can be mixed with one or more additional gases to form a gas mixture. In some examples, the additional gas can include any of the above gases to form a gas mixture, such as hydrogen (H2) and oxygen (O2), H2 and nitrogen (N2), and H2 and ammonia (NH3), and other possible gas mixtures. In some examples, the additional gas can include a carrier gas. Non-limiting examples of the additional gas can include helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), hydrogen (H2), and ammonia (NH3). In some examples, the additional gas can include a co-reactant. Non-limiting examples of the co-reactant include carbon dioxide (CO2), carbon monoxide (CO), water (H2O), methanol (CH3OH), oxygen (O2), ozone (O3), nitrogen (N2), nitrous oxide (N2O), NH3, methane (CH4), ethane (C2H6), acetylene (C2H2), ethylene (C2H4), and diborane (B2H6). In some embodiments, the co-reactant is supplied with the source gas at a flow rate less than the flow rate of the source gas.

[0424] Hydrogen gas can be supplied to a plasma source (e.g., a remote plasma source) to generate hydrogen atom radicals or hydrogen radicals. Once generated, the hydrogen atom radicals can be in an excited energy state (e.g., having an energy of at least 10.2 eV as the first excited state), a fairly low energy state hydrogen atom radical, or a ground state hydrogen atom radical. Similarly, different energy states of different atoms can be generated and employed. By controlling the energy state of the radicals or metastable species, the selective or non-selective decomposition of precursors can be controlled. In some implementations, the process conditions can be provided such that the excited hydrogen atom radicals lose energy or relax to form a fairly low energy state or ground state hydrogen atom radical. For example, the remote plasma source or associated components can be designed such that the residence time of the hydrogen atom radicals diffusing from the remote plasma source to the substrate is greater than the energy relaxation time of the excited hydrogen atom radicals. In other implementations, the process conditions can be provided such that the energy of the excited radicals can be retained. For example, the remote plasma source or associated components can be designed such that the residence time of the hydrogen atom radicals diffusing from the remote plasma source to the substrate is shorter than the energy relaxation time of the excited hydrogen atom radicals. The energy relaxation time of the excited hydrogen atom radicals can be approximately equal to or less than about 1x10 -3 seconds.

[0425] The device features and process control features can be tested and tuned to produce a majority of hydrogen atom radicals in a desired energy state (e.g., an excited energy state, a substantially low energy state, or a ground state). For example, the device can be operated and the charged particles downstream of the plasma source can be tested; that is, near the substrate. The process and device can be tuned until there is substantially no charged material near the substrate.

[0426] Precursors are typically delivered to the environment adjacent to the substrate together with other substances (especially carrier gases). In some implementations, a silicon-containing precursor (Si precursor), a germanium-containing precursor (Ge precursor), a silicon and germanium-containing precursor (SiGe precursor), or a combination of any of these precursors is present together with a high-energy substance, such as a radical substance, a metastable substance, other reactive substances, and even a neutral substance or a carrier gas. Upstream of the deposition reaction surface, the precursor can be mixed with an inert carrier gas. Exemplary inert carrier gases include, but are not limited to, nitrogen (N2), argon (Ar), and helium (He), deuterium (D2), and hydrogen (H2) and combinations thereof.

[0427] Exemplary processes for depositing a silicon-containing layer (Si layer) or a silicon and germanium-containing layer (SiGe layer) as described herein can include CVD operations. In some embodiments, the Si layer or SiGe layer as described herein can be deposited by thermal CVD. In some other embodiments, the Si layer or SiGe layer can be deposited by a plasma-based CVD process, such as an in-situ plasma-enhanced CVD (PECVD) process or a remote plasma CVD (RPCVD) process. In a plasma-based CVD process, the substrate can be exposed to a plasma. As used herein, a plasma can include plasma-activated species generated from a source gas, such as ions, radicals, metastable species, neutral species, and the like. One or more ions, radicals, metastable species, or neutral species of the plasma can interact with the Si precursor, Ge precursor, or SiGe precursor in the environment adjacent to the substrate to deposit the Si layer or SiGe layer. In some embodiments, the plasma includes radicals, such as hydrogen radicals, hydrogen-containing radicals, deuterium-containing radicals, and combinations thereof. For example, a hydrogen-containing radical or a deuterium-containing radical can activate the silicon-containing precursor, the germanium-containing precursor, or the silicon and germanium-containing precursor in the environment adjacent to the substrate to deposit the Si layer or SiGe layer. In this way, hydrogen-containing radicals or deuterium-containing radicals generated by the plasma are used to activate the precursor.

[0428] In other embodiments, the plasma itself can be used to activate the precursor. In some instances, the plasma is a remote plasma source, and the activated precursor is then delivered to the substrate for deposition. In other instances, the plasma is generated in-situ, thus generating an activated precursor, which can then be deposited on the surface of the substrate. The precursor can be activated in any useful way, such as by hydrogen abstraction, selective bond breaking, or decomposing the precursor into smaller molecules, radicals, or other high-energy species. Further conditions, reagents, methods, and processes are described in U.S. Patent Application No. 16 / 044,371, filed Jul. 24, 2018 (published as U.S. Patent Publication No. 2018 / 0330945) and International Publication No. WO 2020 / 023378, both entitled "Remote plasma based deposition of silicon carbide films using silicon-containing and carbon-containing precursors", the entire contents of which are incorporated herein by reference.

[0429] In still other embodiments, the plasma includes metastable species, such as helium-containing metastable species or argon-containing metastable species. For example, the metastable species can activate a Si precursor, a Ge precursor, a SiGe precursor, or a combination thereof in an environment adjacent to the substrate to deposit a Si layer, a SiGe layer, or both types of layers. Such metastable species can be generated remotely and then delivered downstream to a chamber containing the substrate.

[0430] Examples of processes for depositing a Si layer or a SiGe layer as described herein can include the following operations. Any deposition process can be implemented to provide a semiconductor layer. In one example but not limited thereto, the Si layer or the SiGe layer can be deposited by ALD. ALD is a technique that uses sequential self-limiting reactions to deposit thin layers of material. Generally, an ALD cycle includes the operations of delivering and adsorbing at least one reactant to the substrate surface, and then reacting the adsorbed reactant with one or more reactants to form a partial film layer. As an example, a silicon germanium deposition cycle can include the following operations: (i) delivering / adsorbing a silicon-containing precursor (Si precursor) under an optional plasma, (ii) purging the Si precursor from the chamber, (iii) delivering a Si precursor and a germanium-containing precursor (Ge precursor) under an optional plasma, and (iv) purging the Si precursor, the Ge precursor, other gases, the plasma, or a combination thereof from the chamber.

[0431] Each ALD cycle can be used to form a partial layer (e.g., a partial first semiconductor layer or a partial second semiconductor layer), and then each ALD cycle can be repeated m times to form an entire layer (e.g., a first semiconductor layer or a second semiconductor layer). At least about two ALD cycles or more can be included in the disclosed embodiments to deposit the desired layer thickness. For example, between about 2 and about 50 cycles, or between about 2 and about 30 cycles, or between about 2 and about 20 cycles, or between about 2 and about 10 cycles can be performed. In other embodiments, m is from 1 to 100 (e.g., 2 to 100, 3 to 100, 4 to 100, 5 to 100, 6 to 100, 7 to 100, 8 to 100, 9 to 100, 10 to 100, 2 to 50, 3 to 50, 4 to 50, 5 to 50, 6 to 50, 7 to 50, 8 to 50, 9 to 50, 10 to 50, 2 to 30, 3 to 30, 4 to 30, 5 to 30, 2 to 20, 3 to 20, 4 to 20, 5 to 20 and the like). To deposit n number of layers, each ALD cycle is repeated m times to form a single layer, and then each nth layer includes m ALD cycles, thus resulting in m×n cycles being executed to form such layers.

[0432] Unlike chemical vapor deposition (CVD) techniques, the ALD process uses surface-mediated deposition reactions to deposit films in a layer-by-layer manner. In one example of the ALD process, a substrate surface including a large number of surface active sites is exposed to a gas-phase distribution of a first precursor, such as a silicon-containing precursor, which is provided in a certain dose to a chamber containing the substrate. Molecules of this first precursor are adsorbed onto the substrate surface, including chemisorbed substances or physically adsorbed molecules of the first precursor. It should be understood that when a compound is adsorbed onto a substrate surface as described herein, the adsorbed layer may include the compound and derivatives of the compound. For example, the adsorbed layer of a silicon-containing precursor may include the silicon-containing precursor and derivatives of the silicon-containing precursor. After the first precursor dosing, the chamber is then evacuated to remove most or all of the first precursor remaining in the gas phase, such that most or only the adsorbed substances remain. In some implementations, the chamber may not be completely evacuated. For example, the chamber may be evacuated such that the partial pressure of the first precursor in the gas phase is low enough to slow down the reaction. A second set of reactants (e.g., a silicon-containing precursor and a germanium-containing precursor) is introduced into the chamber such that a portion of these molecules react with the first precursor adsorbed on the surface. In some processes, the second set reacts immediately with the adsorbed first precursor. In other embodiments, the second set reacts only after a transient activation source is applied. In some embodiments, a plasma is ignited during the second set of reactant dosing. In some examples, the plasma may be a remote plasma including radicals in a low-energy state or an excited energy state. Such radicals may include hydrogen radicals. Additionally or alternatively, such radicals may include hydrogen-containing radicals, deuterium-containing radicals, nitrogen-containing radicals, argon metastables, helium metastables, or the like. It should be noted that in some embodiments, the radicals may not include those that react with Si, with Ge, or with both Si and Ge. For example, in some implementations, the radicals may not include nitrogen-containing radicals, halogen-containing radicals, oxygen-containing radicals, or the like. These radicals, metastables, and the like may interact with the second set of reactants to form activated silicon-containing precursors (Si precursors), activated germanium-containing precursors (Ge precursors), or activated forms of both Si precursors and Ge precursors that react with the adsorbed first precursor. These radicals, metastables, and the like may alternatively or additionally interact with the adsorbed first precursor to activate the adsorbed first precursor. The chamber may then be evacuated again to remove the unbound second set of molecules. As described above, in some embodiments, the chamber may not be completely evacuated. Additional ALD cycles may be utilized to build up the film thickness.

[0433] In certain embodiments, the ALD first precursor dosing partially saturates the substrate surface. In some embodiments, the dosing stage of the ALD cycle ends before the precursor contacts the substrate to uniformly saturate the surface. Typically, the precursor flow is shut off or diverted at this time, and only the purge gas flows. By operating in this sub-saturated regime, the ALD process shortens the cycle time and increases throughput. However, since precursor adsorption is not limited by saturation, the adsorbed precursor concentration may vary slightly across the substrate surface. An example of an ALD process operating in a sub-saturated regime is provided in U.S. Patent Application No. 14 / 061,587, filed Oct. 23, 2013, and titled "Subsaturated atomic layer deposition and conformal film deposition" (now U.S. Patent No. 9,355,839), the entire content of which is incorporated herein by reference.

[0434] As described, in some implementations, the ALD method includes plasma activation. As described herein, the ALD methods and apparatuses described herein can be conformal film deposition (CFD) methods, which are outlined in U.S. Patent Application No. 13 / 084,399, filed Apr. 11, 2011, and titled "Plasma activated conformal film deposition" (now U.S. Patent No. 8,728,956) and U.S. Patent Application No. 13 / 084,305, filed Apr. 11, 2011, and titled "Silicon nitride films and methods" (published as U.S. Patent Publication No. 2011 / 0256734), the entire content of which is incorporated herein by reference.

[0435] In some embodiments, a plasma can be used during deposition, such as during the exposure to a Si precursor, a Ge precursor, or a SiGe precursor. Plasma energy can be provided to activate the reactants into high-energy species, ions, radicals, metastable species, and other activated species, which react with the adsorbed layer of the first precursor. In various embodiments, the plasma is an in-situ plasma such that the plasma is formed directly above the substrate surface in the chamber.

[0436] The in-situ plasma can be at about 0.2122 W / cm 2 to about 2.122 W / cm 2Power / substrate area ignition therebetween. For example, for a chamber processing four 300 mm wafers, the power range can be from about 150 W to about 6000 W, or from about 600 W to about 6000 W, or from about 800 W to about 4000 W. For example, a plasma can be generated by applying a radio frequency (RF) field to a gas using two capacitively coupled plates. The RF field ionizes the gas between the plates to ignite the plasma, thereby generating free electrons in the plasma discharge region. These electrons are accelerated by the RF field and may collide with gas-phase reactant molecules. The collisions of these electrons with the reactant molecules may form radical species that participate in the deposition process. It should be understood that the RF field can be coupled through any suitable electrode. In various embodiments, a high-frequency plasma with a frequency of at least about 13.56 MHz, or at least about 27 MHz, or at least about 40 MHz, or at least about 60 MHz is used. In some embodiments, a microwave-based plasma can be used. Non-limiting examples of the electrodes include a process gas distribution showerhead and a substrate support pedestal. It should be understood that in addition to the capacitive coupling of the RF field with the gas, the plasma can also be formed by one or more suitable methods. In some embodiments, the plasma is a remote plasma such that the reactants are ignited in a remote plasma generator upstream of the chamber and then transported to the chamber containing the substrate. Further apparatus and operations are described in U.S. Patent Application No. 63 / 261,533, filed on September 23, 2021, and entitled "Remote plasma deposition with electrostatic clamping", the entire content of which is incorporated herein by reference. High-energy species

[0437] As described herein, high-energy species can be used during any operation, including one or more pre-cleaning, pre-treatment, deposition, reactor cleaning, or reactor treatment operations. High-energy species can include any species that react with one or more of the components provided during pre-cleaning, pre-treatment, deposition, reactor cleaning, or reactor treatment operations. Such components can include precursors, reagents, gases, deposition layers, substrates, surfaces of substrates, chambers, surfaces of chambers, and the like.

[0438] Non-limiting examples of high-energy substances include free radicals, metastable substances, ions, neutral substances, plasmas, photons, radiation (e.g., ultraviolet radiation), excited molecules, excited atoms, reactive substances (e.g., reactive precursors, reactive reagents, or reactive gases), activated substances (e.g., activated precursors, activated reagents, or activated gases), catalytically activated substances (e.g., catalytically activated precursors, catalytically activated reagents, or catalytically activated gases), or other high-energy substances described herein. In one non-limiting embodiment, the metastable substance has an energy of about 0.01 - 1 eV. In another non-limiting embodiment, the ion has an energy of about 100 - 1000 eV. In yet another non-limiting embodiment, the high-energy substance has an energy of about 0.01 - 1000 eV. In some non-limiting examples, any description herein regarding free radicals and metastable substances may encompass any high-energy substance described herein.

[0439] High-energy substances can be generated in any useful manner. The methods for generating high-energy substances can occur in situ (inside the chamber) or ex situ (outside the chamber), and the high-energy substances are delivered into the chamber. In one embodiment, high-energy substances can be generated by using plasmas, for example, by using remote plasma sources or in situ plasma sources. In another embodiment, high-energy substances can be generated without using plasmas. In still other embodiments, high-energy substances can be generated by using plasma sources (e.g., remote plasma sources or in situ plasma sources) and non-plasma sources (e.g., catalyst sources, radiation sources, and the like).

[0440] In another embodiment, high-energy substances can be generated by using catalysts. For example, catalysts can be used to regenerate or generate hydrogen or deuterium, as well as high-energy substances including hydrogen or deuterium. Non-limiting catalysts can include platinum (Pt), iridium (Ir), palladium (Pd), rhodium (Rh), nickel (Ni), and combinations thereof.

[0441] In yet another embodiment, high-energy substances can be generated by using radiation (e.g., ultraviolet radiation). The radiation can be provided by any useful radiation source, including lamps, lasers, light-emitting diodes (LEDs), and the like, including their pulsed waveforms and continuous waveforms.

[0442] In one embodiment, the energetic material includes an activated form of any of the reagents described herein. For example, the energetic material can include an activated form of a precursor (e.g., a first precursor, a second precursor, or an optional third precursor). In one instance, pre-cleavage of the precursor can include using any energy source or any energetic material to provide a more reactive form of the precursor. The precursor can be activated in any useful manner, such as by hydrogen abstraction, selective bond breaking, non-selective bond breaking, or decomposing the precursor into smaller molecules, free radicals, or other energetic materials. Any useful energy source can be used for cleavage, such as providing a catalyst, a radiation source (e.g., a UV source), a plasma source (e.g., a remote plasma), and the like in the presence of the precursor. Pre-cleavage can occur inside the chamber (e.g., close to or away from the substrate) or outside the chamber (and then transported into the chamber). Precursor

[0443] Precursors can include those containing silicon atoms (e.g., silicon-containing precursors), germanium atoms (e.g., germanium-containing precursors), or both (e.g., silicon- and germanium-containing precursors). Combinations of precursors can be used during deposition. Any precursor having a hydrogen atom herein can include a deuterium atom or its hydrogen atom is replaced by a deuterium atom.

[0444] Si-containing precursors can be employed to provide Si-containing layers. In one embodiment, the Si-containing precursor is a silane (Si a H b ), a silane halide (Si a H b X c ), and a silicon halide (Si a X b ), where X is a halogen, and a, b, and c are each independently an integer from 1 to 20.

[0445] Non-limiting silane compounds (e.g., silane or polysilane) include Si a H 2a+2 , where a is 1 - 8; or Si a H 2a , where a is 3 - 8. Examples of silane compounds include silane (SiH4), disilane (Si2H6), trisilane (Si3H8), cyclotrisilane (Si3H6), tetrasilane (Si4H 10 ), cyclotetrasilane (Si4H8), pentasilane (Si5H 12 ), cyclopentasilane (Si5H 10 ), hexasilane (Si6H 14 ), cyclohexasilane (Si6H 12 ), heptasilane (Si7H 16 ), cycloheptasilane (Si7H 14 ), octasilane (Si8H 18 ) and the like.

[0446] Non-limiting silane halide compounds include Si a H b X c , where a is from 1 to 8, b is from 1 to 18, and c is from 1 to 18. In some embodiments, b + c = 2a + 2. Examples of silane halides include monochlorosilane (MCS, SiH3Cl), dichlorosilane (DCS, SiH2Cl2), trichlorosilane (TCS, SiHCl3), 1,2-dichloro-disilane (Si2H4Cl2), 1,2,3-trichlorosilane (Si3H5Cl3), and the like.

[0447] Non-limiting silicon halide compounds (or halosilanes) include Si a X 2a+2 , where a is from 1 to 8; or Si a X 2a , where a is from 3 to 8. Examples of silicon halide compounds include silicon tetrachloride (STC, SiCl4), hexachloro-disilane (HCDS, Si2Cl6), octachloro-trisilane (OCTS, Si3Cl8), or combinations thereof.

[0448] Ge-containing precursors can be used to provide Ge-containing layers. Ge-containing precursors include germanium hydrides (Ge a H b ), germanium hydride halides (Ge a H b X c ), and germanium halides (Ge a X b ), where X is a halogen, and a, b, and c are each independently integers from 1 to 20.

[0449] Non-limiting germanium hydride compounds (e.g., germane or polygermane) include Ge a H 2a+2, , where a is from 1 to 8; or Ge a H 2a， , where a is from 3 to 8. Examples of germanium hydride compounds include germane (GeH4), digermane (Ge2H6), trigermane (Ge3H8), tetragermane (Ge4H 10 ), pentagermane (Ge5H 12 ), and the like.

[0450] Non-limiting germanium hydride halide compounds include Ge a H b X c, where a is from 1 to 8, b is from 1 to 18, and c is from 1 to 18. In some embodiments, b + c = 2a + 2. Examples of germane halides include dichlorogermane (GeH2Cl2), trichlorogermane (GeHCl3), and the like.

[0451] Non-limiting germanium halide compounds (or halogermanes) include Ge a X 2a+2 , where a is from 1 to 8; or Ge a X 2a , where a is from 3 to 8. Examples of germanium halide compounds include germanium tetrachloride (GeCl4), hexachloroethagermane (Ge2Cl6), or combinations thereof.

[0452] The precursor may include Si and Ge atoms. In one example, the precursor is an Si- and Ge-containing precursor, such as germylsilane (H3Ge-SiH3). In some embodiments, the Si- and Ge-containing precursor may include an Si-Ge hydride precursor, such as Ge a H b Si c , where a is from 1 to 8, b is from 1 to 18, and c is from 1 to 8. In certain embodiments, the precursor includes (H3Ge) a SiH 4-a , where a = 1 - 4, or (H3Si) c GeH 4-c , where c = 1 - 4.

[0453] The precursor can be provided at any useful flow rate. In one embodiment, the flow rate of the precursor can be greater than 10 sccm, or greater than 50 sccm, or greater than 100 sccm, or greater than 200 sccm; or about 20 sccm to 300 sccm. A carrier gas can be used with the precursor, where the carrier gas can include a hydrogen-containing reagent (e.g., H2), a deuterium-containing reagent (e.g., D2), an inert gas (e.g., Ar, N2, or He), or a combination thereof. The carrier gas can have any available flow rate, such as about 0.01 sccm to 200 sccm. The volume ratio of the precursor to the carrier gas in the deposition chamber can be between 2000:1 and 1:1. The pressure during deposition using such a precursor can be about 0.2 Torr to 0.6 Torr at a temperature of about 350 °C to 530 °C; or a pressure of about 300 Torr or less at a temperature of about 700 °C or lower.

[0454] The precursor can be used in combination with a reducing agent. Non-limiting reducing agents can include H2, BH3, or B2H6.

[0455] In other embodiments, the one or more precursors may be used in combination with dopant precursors to introduce one or more dopants into the layer. Dopants can include any atom, including Group IV atoms (e.g., carbon (C), silicon (Si), germanium (Ge), tin (Sn), and the like); Group III atoms (e.g., boron (B), aluminum (Al), gallium (Ga), indium (In), thallium (Tl), or combinations thereof) or Group V atoms (e.g., nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb), bismuth (Bi), or combinations thereof).

[0456] Dopant precursors can include Group IV atoms, Group III atoms, Group V atoms, or combinations thereof with any useful ligands. In one embodiment, the dopant precursor includes Z a R b , where Z is a Group IV atom, a Group III atom, a Group V atom, or a combination thereof. Each R is independently a ligand; a is 1 - 8; and b is 2 - 18. Non-limiting examples of ligands (e.g., R) independently include H, halogen, hydroxyl, optionally substituted aliphatic groups, optionally substituted alkyl groups, optionally substituted alkenyl groups, optionally substituted alkynyl groups, optionally substituted cycloalkyl groups, optionally substituted heteroaliphatic groups, optionally substituted alkoxy groups, optionally substituted acyl groups, optionally substituted aromatic groups, optionally substituted aryl groups, cyclopentadienyl groups, optionally substituted bis(trialkylsilyl)amino (e.g., -N(SiR 1 R 2 R 3 )2), optionally substituted alkanoyloxy (e.g., acetate), diketonato (e.g., -OC(R 1 )-Ak-(R 2 )CO-), bidentate chelating diazo (e.g., -N(R 1 )-Ak-N(R 1 )-), optionally substituted silyl groups, optionally substituted siloxy groups, and the like. Additional other non-limiting examples of ligands (e.g., R) include H, methyl (-Me), ethyl (-Et), n-propyl (-nPr), isopropyl (-iPr), n-butyl (-nBu), isobutyl (-iBu), sec-butyl (-sBu), tert-butyl (-tBu), methoxy (-OMe), ethoxy (-OEt), n-propoxy (-O-nPr), isopropoxy (-O-iPr), n-butoxy (-O-nBu), isobutoxy (-O-iBu), sec-butoxy (-O-sBu), tert-butoxy (-O-tBu), dimethylamino (-NMe2), diethylamino (-NEt2), methylethylamino (-NMeEt), and the like.

[0457] For any use herein, C-containing precursors can include hydrocarbon precursors or any precursors having one or more organic ligands as described herein (e.g., ligands selected from the group consisting of optionally substituted aliphatics, optionally substituted alkyls, optionally substituted alkenyls, optionally substituted alkynyls, optionally substituted heteroaliphatics, optionally substituted heteroalkyls, optionally substituted alkoxys, optionally substituted aminos, and the like). Non-limiting hydrocarbon precursors can be used, including those having the formula C x H y , where x is an integer between 2 and 10, and y is an integer between 2 and 24. Examples include methane (CH4), acetylene (C2H2), ethylene (C2H4), propylene (C3H6), butane (C4H 10 ), cyclohexane (C6H 12 ), benzene (C6H6), and toluene (C7H8).

[0458] For any use herein, Ge-containing precursors can include germane, germyl halides, germanium halides, alkylgermanes, or alkoxygermanes. Further examples include Ge a R 2a+2 , where a is 1 - 8; Ge a R 2a , where a is 3 - 8; or GeR4, where each R is independently any ligand as described herein. In some embodiments, the Ge-containing precursor is germane (GeH4), tetramethylgermane (GeMe4), tetraethylgermane (GeEt4), tetra-n-butylgermane (Ge[nBu]4), tetraethoxygermane (Ge[OEt]4), tris(2,2,6,6-tetramethyl-3,5-heptanedionato)gallium (Ga[thd]3, where thd is 2,2,6,6-tetramethyl-3,5-heptanedionato), and the like.

[0459] For any use herein, Sn-containing precursors can include stannane, stannyl halides, tin halides, alkyltins, alkoxytins, or aminotins. Further examples include Sn a R 2a+2 , where a is 1 - 8; Sn a R 2a , where a is 3 - 8; or SnR4, where each R is independently any ligand as described herein. In some embodiments, the tin-containing precursor includes SnR or SnR2 or SnR4 or R3SnSnR3, where each R is independently H, halogen, optionally substituted C 1-12 alkyl, optionally substituted C 1-12 alkoxy, optionally substituted amino (e.g., -NR 1 R 2 ), optionally substituted C 2-12Alkenyl, optionally substituted substituted C 2-12 Alkynyl, optionally substituted C 3-8 Cycloalkyl, optionally substituted aryl, cyclopentadienyl, optionally substituted bis(trialkylsilyl)amino (e.g., -N(SiR 1 R 2 R 3 )2), optionally substituted alkanoyloxy (e.g., acetate), diketonato (e.g., -OC(R 1 )-Ak-(R 2 )CO-), or bidentate chelating diaza (e.g., -N(R 1 )-Ak-N(R 1 )-). In certain embodiments, each R 1 , R 2 and R 3 is independently H or C 1-12 alkyl (e.g., methyl, ethyl, isopropyl, tert-butyl or neopentyl); Ak is optionally substituted C 1-6 alkylene. In certain embodiments, each R is independently halogen, optionally substituted C 1-12An alkoxy group, an optionally substituted amino group, an optionally substituted aryl group, a cyclopentadienyl group, or a diketonate group. Non-limiting tin precursors include SnF2, SnH4, SnBr4, SnCl4, SnI4, tetramethyltin (SnMe4), tetraethyltin (SnEt4), trimethyltin chloride (SnMe3Cl), dimethyldichlorotin (SnMe2Cl2), methyltrichlorotin (SnMeCl3), tetraallyltin, tetravinyltin, hexaphenylditin(IV) (Ph3Sn-SnPh3, where Ph is phenyl), dibutyldiphenyltin (SnBu2Ph2), trimethyl(phenyl)tin (SnMe3Ph), trimethyl(phenylethynyl)tin, tricyclohexyltin hydride, tributyltin hydride (SnBu3H), dibutyltin diacetate (SnBu2(CH3COO)2), tin(II) acetylacetonate (Sn(acac)2), SnBu3(OEt), SnBu2(OMe)2, SnBu3(OMe), Sn(t-BuO)4, Sn(n-Bu)(t-BuO)3, tetrakis(dimethylamino)tin (Sn(NMe2)4), tetrakis(ethylmethylamino)tin (Sn(NMeEt)4), tetrakis(diethylamino)tin(IV) (Sn(NEt2)4), (dimethylamino)trimethyltin(IV) (Sn(Me)3(NMe2), Sn(i-Pr)(NMe2)3, Sn(n-Bu)(NMe2)3, Sn(s-Bu)(NMe2)3, Sn(i-Bu)(NMe2)3, Sn(t-Bu)(NMe2)3, Sn(t-Bu)2(NMe2)2, Sn(t-Bu)(NEt2)3, Sn(tbba), Sn(II)(1,3-bis(1,1-dimethylethyl)-4,5-dimethyl-(4R,5R)-1,3,2-diazastannolidin-2-ylidene), or bis[bis(trimethylsilyl)amino]tin (Sn[N(SiMe3)2]2).

[0460] For any use herein, the B precursor may include a borohydride, a borohalide, a boron halide, an alkyl borane, or an alkyl borate. Further examples include B a R a+2, where a is from 1 to 8; B2R4; B2R6; or BR3, where each R is independently any ligand described herein. In some embodiments, the B-containing precursor is borane (BH3), diborane (B2H6), triborane (B3H7), boron tribromide (BBr3), boron trichloride (BCl3), boron trifluoride (BF3), trimethylborane (BMe3), triethylborane (BEt3), triphenylborane (BPh3), boric acid (B(OH)3), trimethyl borate (B[OMe]3), triethyl borate (B[OEt]3), triisopropyl borate (B[O-iPr]3), tributyl borate (B[O-nBu]3), tetra(dimethylamino)diborane (B2[NMe2]4) and the like.

[0461] For any use herein, the Al-containing precursor may include alkylaluminum or aluminoxane. Further examples include Al a R a+2 , where a is from 1 to 8; or AlR3, where each R is independently any ligand described herein. In some embodiments, the Al-containing precursor is trimethylaluminum [AlMe3], triethylaluminum [AlEt3], triisobutylaluminum (Al[iBu]3), dimethylaluminum isopropoxide (Me2Al[O-iPr]), triethyl(tri-sec-butoxy)dialuminum (Et3Al2[O-sBu]3), diethyl(tetra-sec-butoxy)dialuminum (Et2Al2[O-sBu]4), tetraethyl(di-sec-butoxy)dialuminum (Et4Al2[O-sBu]2), aluminum ethoxide (Al[OEt]3), aluminum isopropoxide (Al[O-iPr]3), aluminum sec-butoxide (Al[O-sBu]3), aluminum acetylacetonate (Al[CH3COCHCOCH3]3 or Al[acac]3), tris(2,2,6,6-tetramethyl-3,5-heptanedionato)aluminum (Al[thd]3, where thd is 2,2,6,6-tetramethyl-3,5-heptanedionato) and the like.

[0462] For any use herein, the Ga-containing precursor may include alkylgallium or aminogallium. Further examples include Ga a R a+2 , where a is from 1 to 8; or G a R3, where each R is independently any ligand described herein. In some embodiments, the Ga-containing precursor is trimethylgallium (Ga[Me]3), triethylgallium (Ga[Et]3), gallium acetylacetonate (Ga[CH3COCHCOCH3]3 or Ga[acac]3), bis(μ-dimethylamino)tetrakis(dimethylamino)digallium (Ga2[NMe2]6) and the like.

[0463] For any use herein, the In-containing precursor may include InR3, where each R is independently any ligand described herein, such as a halogen, an optionally substituted C 1-12 alkyl (such as methyl, ethyl, isopropyl, tert-butyl, and neopentyl), or diketonato (such as -OC(R 4 )-Ak-(R 5 )CO-, where each R 4 and R 5 is independently H or C 1-12 alkyl). Non-limiting In-containing precursors include indium trichloride (InCl3), trimethylindium (InMe3), cyclopentadienylindium (InCp, where Cp is cyclopentadienyl), indium acetylacetonate (In[acac]3, where acac is acetylacetonato), and the like.

[0464] For any use herein, the Tl-containing precursor may include TlR, where each R is independently any ligand described herein. Non-limiting Tl-containing precursors include thallium ethoxide (Tl[OEt]), thallium cyclopentadienyl (Tl[Cp], where Cp is cyclopentadienyl), thallium acetylacetonate (Tl[acac]), and the like.

[0465] For any use herein, the N-containing precursor includes any one having at least one N atom, for example, nitrogen gas (N2), ammonia (NH3), hydrazine (N2H4), nitric oxide (NO), nitrous oxide (N2O), amines (such as amines with carbon), such as methylamine, dimethylamine, ethylmethylamine, ethylamine, isopropylamine, tert-butylamine, di-tert-butylamine, cyclopropylamine, sec-butylamine, cyclobutylamine, isoamylamine, 2-methylbutan-2-amine, trimethylamine, diisopropylamine, diethylisopropylamine, di-tert-butylhydrazine, and amines containing aromatics (such as aniline, pyridine, and benzylamine). Other additional N-containing precursors may include nitriles (such as acetonitrile), amides, N-containing heterocyclic compounds, or amino alcohols (such as ethanolamine). The amine may be a primary, secondary, tertiary, or quaternary amine (such as a tetraalkylammonium compound). The N-containing precursor may contain heteroatoms other than N, such as hydroxylamine, tert-butoxycarbonylamine, and N-tert-butylhydroxylamine are N-containing precursors. In other embodiments, the N-containing precursor may include any precursor herein having one or more optionally substituted amino groups.

[0466] For any use herein, P-containing precursors include any one having at least one P atom, such as phosphates, phosphines, phosphorus halides, organophosphorus compounds, and the like. Non-limiting P-containing precursors include phosphine (PH3), alkyl phosphates (e.g., trimethyl phosphate (PO[OMe]3) or triethyl phosphate (PO[OEt]3)), trimethyl phosphite (P[OMe]3), tris(dimethylamino)phosphine (P[NMe2]3), phosphorus halides (e.g., phosphorus trichloride (PCl3)), trimethylsilylphosphine (P[SiMe3]3), and phosphorus oxychloride (POCl3) and the like.

[0467] For any use herein, As-containing precursors include As a R a+2 , where a is 1 - 8; or AsR3, where each R is independently any ligand described herein. Non-limiting As-containing precursors include arsenides, alkylarsines, alkoxyarsines, and aminoarsine chemical families, and include but are not limited to the following specific compounds: arsine (AsH3), triethyl arsenate (ArO[OEt]3), trimethylarsine (As[Me]3), triethylarsine (As[Et]3), triphenylarsine (As[Ph]3, where Ph is phenyl), triphenylarsine oxide (AsO[Ph]3), tris(dimethylamino)arsine (As[NMe2]3), and As(OR)3, where R is -Me, -Et, or other optionally substituted alkyl (including saturated and unsaturated alkyls), and other similar arsenic-containing compounds.

[0468] For any use herein, Sb-containing precursors may include SbR3, where each R is independently any ligand described herein, including halogen, optionally substituted C 1-12 alkyl (e.g., methyl, ethyl, isopropyl, tert-butyl, and neopentyl), optionally substituted C 1-12 alkoxy, or optionally substituted amino (e.g., -NR 1 R 2 , where each R 1 and R 2 is independently H or optionally substituted C 1-12 alkyl). Non-limiting antimony precursors include antimony trichloride (SbCl3), antimony ethoxide (Sb[OEt]3), antimony n-butoxide (Sb[O-nBu]3), and tris(dimethylamino)antimony (Sb[NMe2]3).

[0469] For any use herein, Bi-containing precursors may include BiR3, where each R is independently any ligand described herein, including halogen, optionally substituted C 1-12 alkyl, mono-C 1-12 alkylamine group (e.g., -NR 1 H), di-C 1-12Alkylamino (e.g., -NR 1 R 2 ), optionally substituted aryl, optionally substituted bis(trialkylsilyl)amino (e.g., -N(SiR 1 R 2 R 3 )2), or diketonato (e.g., -OC(R 4 )-Ak-(R 5 )CO-). In certain embodiments, each R 1 , R 2 , and R 3 is independently C 1-12 alkyl (e.g., methyl, ethyl, isopropyl, tert-butyl, or neopentyl); each R 4 and R 5 is independently H or optionally substituted C 1-12 alkyl (e.g., methyl, ethyl, isopropyl, tert-butyl, or neopentyl). Non-limiting bismuth precursors include bismuth chloride (BiCl3), trimethylbismuth (BiMe3), triphenylbismuth (BiPh3), tris(dimethylamino)bismuth (Bi[NMe2]3), Bi[N(SiMe3)2]3, and tris(2,2,6,6-tetramethyl-3,5-heptanedionato)bismuth (Bi[thd]3, where thd is 2,2,6,6-tetramethyl-3,5-heptanedionato).

[0470] In another embodiment, one or more insulator or dielectric materials can be deposited. Non-limiting insulator precursors can include silicon-containing precursors, nitrogen-containing precursors (e.g., any of those described herein), oxygen-containing precursors (e.g., oxygen, ozone, carbon monoxide, carbon dioxide, nitrous oxide, water, alkyl alcohols such as isopropyl alcohol and the like), carbon-containing precursors (e.g., any of those described herein), organosilicon precursors, organonitrogen precursors, organooxygen precursors, and any combination thereof.

[0471] Additional other non-limiting precursors include silanes, organosilanes, halosilanes, aminosilanes, alkoxysilanes, silanols, hydrocarbons and the like, and any of those described herein. Other examples of silicon-containing precursors include SiR4, where each R is independently any ligand described herein, includ...

Claims

1. A method for forming a heterolayer on a substrate, the method comprising: (a) forming a first layer by flowing a first precursor into a reaction chamber in the presence of high-energy species and towards the substrate, wherein the high-energy species react with the first precursor to deposit the first layer on the substrate, and wherein the substrate is disposed within the reaction chamber; (b) forming a second layer by flowing a second precursor and optionally a third precursor into the reaction chamber in the presence of high-energy species and towards the substrate, wherein the high-energy species react with the second precursor or the optional third precursor to deposit the second layer on the substrate; and (c) repeating (a) and (b) until a predetermined number of layers have been deposited on the substrate, optionally wherein the first layer has an etching behavior different from that of the second layer.

2. The method according to claim 1, wherein the high-energy species comprise one or more of free radicals, plasma-generated free radicals, metastable species, plasma-generated metastable species, ions, or plasma-generated ions.

3. The method according to claim 1, wherein the high-energy species comprise at least one of hydrogen-containing free radicals, deuterium-containing free radicals, helium-containing metastable species, or argon-containing metastable species.

4. The method according to claim 1, wherein the high-energy material is characterized by having a density of at least about 10 8 cm -3 at the surface of the substrate.

5. The method according to claim 1, wherein the second layer comprises a sacrificial layer.

6. The method according to claim 1, further comprising, before operation (a) or (b): (a′″) depositing a buffer layer between the substrate and the first layer or between the substrate and the second layer.

7. The method according to claim 1, wherein operation (a) or (b) occurs after an initial layer has been deposited on the substrate.

8. The method according to claim 1, wherein (1) the high-energy species are generated in a remote plasma source located upstream of the reaction chamber, or (2) the high-energy species are generated in situ in a portion of the reaction chamber, or (3) the high-energy species are generated by plasma.

9. The method according to claim 1, further comprising (1) heating the substrate using a radiative heat source, or (2) providing an interface layer between the first layer and the second layer.

10. The method according to claim 1, further comprising: (1) exposing the substrate to plasma after operation (a), between operations (a) and (b), or after operation (b); or (2) performing at least one of operations (a′) or (a″) before operation (a) or after operation (c): (a′) pre-cleaning the substrate to provide a pre-cleaned surface of the substrate; or (a″) pre-treating the surface of the substrate to provide a pre-treated surface of the substrate; or (3) performing at least one of operations (c′) or (c″) before operation (a) or after operation (c): (c′) performing reactor cleaning of the reaction chamber by removing contaminants from the environment or surface within the reaction chamber after removing the substrate from the reaction chamber or before providing the substrate to the reaction chamber; or (c'') After operation (c'), the reactor is processed by passivating the environment or the surface in the reaction chamber.

11. An apparatus for forming a heterolayer on a substrate, the apparatus comprising: a reaction chamber; a substrate support disposed in the reaction chamber and configured to support a substrate; a plasma source; and one or more controllers configured with instructions for performing the following operations: (a) forming a first layer by flowing a first precursor into the reaction chamber and towards the substrate in the presence of high-energy substances generated by plasma, wherein the high-energy substances generated by the plasma react with the first precursor to deposit the first layer on the substrate; (b) forming a second layer by flowing a second precursor and an optional third precursor into the reaction chamber and towards the substrate in the presence of high-energy substances generated by plasma, wherein the high-energy substances generated by the plasma react with the second precursor and the optional third precursor to deposit the second layer on the substrate; and (c) repeating (a) and (b) until a predetermined number of layers have been deposited on the substrate, optionally wherein the first layer has an etching behavior different from that of the second layer.

12. A method for epitaxially depositing a film, the method comprising: pre-cleaning the surface of a substrate to remove oxides; pre-treating the surface of the substrate to provide a hydrophobic surface or a passivated surface; epitaxially depositing at least one of a first layer or a second layer in an epitaxial chamber in the presence of plasma and on the pre-cleaned and pre-treated surface; removing the substrate from the epitaxial chamber; and performing reactor cleaning, wherein the performing of the reactor cleaning is performed in at least one of the following cases: before providing the substrate in the epitaxial chamber or after removing the substrate from the epitaxial chamber.

13. The method according to claim 12, wherein the pre-cleaning comprises delivering a halogen-containing reagent, a halogen-containing vapor, or a halogen-containing plasma.

14. The method according to claim 12, further comprising, before the epitaxial deposition: depositing a buffer layer between the substrate and the first layer or between the substrate and the second layer.

15. A method for forming a stack, the method comprising: pre-cleaning a substrate to provide a pre-cleaned surface; pre-treating the pre-cleaned surface of the substrate to provide a pre-cleaned and pre-treated surface; epitaxially depositing a plurality of alternating first layers and second layers in an epitaxial chamber in the presence of plasma and on the pre-cleaned and pre-treated surface of the substrate; removing the substrate from the epitaxial chamber; and performing reactor cleaning on the epitaxial chamber, wherein the performing of the reactor cleaning is performed in at least one of the following cases: before providing the substrate in the epitaxial chamber or after removing the substrate from the epitaxial chamber.

16. The method according to claim 15, wherein the pre-cleaning comprises exposing the surface of the substrate to a halogen-containing reagent, a halogen-containing vapor, a halogen-containing plasma, a hydrogen-containing reagent, a deuterium-containing reagent, a hydrogen-containing plasma, or a deuterium-containing plasma.

17. The method according to either claim 12 or 15, wherein the epitaxial deposition comprises remote plasma.

18. The method according to claim 15, further comprising, (1) after the epitaxial deposition: depositing a hard mask on the surfaces of the plurality of alternating first and second layers; or (2) before the epitaxial deposition: depositing a buffer layer between the substrate and the plurality of alternating first and second layers.

19. A system or apparatus, comprising: at least one pre-cleaning chamber comprising a substrate support configured to support a substrate; at least one epitaxial chamber comprising a substrate support configured to support a substrate; a plasma source; at least one outlet for coupling to a vacuum; one or more process gas inlets coupled to one or more fluorine-containing reactant sources; one or more process gas inlets coupled to one or more hydrogen-containing reactant sources or deuterium-containing reactant sources; one or more process gas inlets coupled to one or more first precursor sources; one or more process gas inlets coupled to one or more second precursor sources; one or more optional process gas inlets coupled to one or more optional third precursor sources; one or more process gas inlets coupled to one or more halogen-containing reactant sources; and one or more controllers for controlling the operation, wherein the one or more controllers comprise machine-readable instructions for performing one or more cycles of the following operations: directing the one or more fluorine-containing reactants to the pre-cleaning chamber; transferring the substrate from the pre-cleaning chamber to the epitaxial chamber under vacuum; directing the one or more hydrogen-containing reactants or deuterium-containing reactants to the epitaxial chamber; cyclically directing at least one of the one or more first precursors, second precursors, or optional third precursors to the epitaxial chamber; transferring the substrate out of the epitaxial chamber; and directing the one or more halogen-containing reactants to the epitaxial chamber.

20. A system or apparatus, comprising: at least one pre-cleaning chamber comprising a substrate support configured to support a substrate; at least one pre-treatment chamber comprising a substrate support configured to support a substrate; at least one epitaxial chamber comprising a substrate support configured to support a substrate; a plasma source; at least one outlet for coupling to a vacuum; one or more process gas inlets coupled to one or more fluorine-containing reactant sources; one or more process gas inlets coupled to one or more hydrogen-containing reactant sources or deuterium-containing reactant sources; one or more process gas inlets coupled to one or more first precursor sources; one or more process gas inlets coupled to one or more second precursor sources; One or more optional process gas inlets coupled to one or more optional third precursor sources; One or more process gas inlets coupled to one or more halogen-containing reactant sources; And One or more controllers for controlling operations, wherein the one or more controllers include machine-readable instructions for performing one or more cycles of the following operations: Directing the one or more fluorine-containing reactants to the pre-cleaning chamber; Transferring the substrate from the pre-cleaning chamber to the pre-treatment chamber under vacuum; Directing the one or more hydrogen-containing reactants or deuterium-containing reactants to the pre-treatment chamber; Transferring the substrate from the pre-treatment chamber to the epitaxial growth chamber under vacuum; Cyclically directing at least one of the one or more first precursors, second precursors, or optional third precursors to the epitaxial growth chamber; Transferring the substrate out of the epitaxial growth chamber; And Directing the one or more halogen-containing reactants to the epitaxial growth chamber.

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