Method for depositing a hafnium lanthanum oxide film on a substrate by a cyclic deposition process in a reaction chamber

Abstract

Disclosed is a method for depositing a hafnium lanthanum oxide film on a substrate, which is carried out by cyclic deposition in a reaction chamber. The method may include: depositing a hafnium oxide film on the substrate using a first sub-cycle of the cyclic deposition process, and depositing a lanthanum oxide film using a second sub-cycle of the cyclic deposition process.

Description

Technical Field

[0001] The present disclosure generally relates to methods for depositing hafnium lanthanum oxide films by a cyclic deposition process, and to a particular method for depositing hafnium lanthanum oxide films by a cyclic deposition process including a first sub-cycle and a second sub-cycle. Background Art

[0002] For many years, silicon dioxide (SiO2) has been used in semiconductor substrates for components such as transistor gate dielectrics and capacitor dielectrics. However, as the size of circuit components decreases, the electrical performance characteristics of SiO2 result in undesirable effects such as increased leakage current. Controlling leakage current to maintain high-speed and low-power performance presents a challenge when using older dielectrics (such as SiO2) in the manufacture of next-generation integrated circuit geometries.

[0003] More recent processes, especially those using fabrication geometries less than 65 nm, have begun to include high dielectric constant ("high-k") insulators in semiconductor manufacturing. Some chip manufacturers now rely on high-k dielectrics, especially for process geometries of 45 nm and smaller. Replacing SiO2 gate dielectrics with high-k dielectrics is important for achieving smaller device geometries while controlling leakage and other electrical performance criteria.

[0004] Although the use of high-k dielectrics allows for the scaling down of integrated circuit components (such as transistor gate dielectrics), new performance issues arise due to their use. For example, when conventional gate electrodes are paired with high-k dielectrics (such as HfO2), problems such as low yield and poor threshold voltage (V th ) control must be addressed.

[0005] The benefits of using ternary oxides in high-k dielectric applications have been studied. Specifically, compared to other high-k dielectrics (such as HfO2), films made of hafnium lanthanum oxide (HfLaO x ) are promising in terms of providing high dielectric constant values, reducing crystallization temperature, improving yield, and better threshold voltage (V th ) control. In addition, unlike other Hf-based amorphous materials, such as HfSiO x or HfAlO x , the permittivity of HfLaO x remains high (>20). Thus, HfLaO x dielectrics are desirable in terms of electrical performance criteria, but manufacturing HfLaO x dielectrics on substrates in a time- and cost-efficient manner presents a challenge.

[0006] Accordingly, a method for depositing a high-k hafnium lanthanum oxide film on a substrate would be highly desirable. Summary of the Invention

[0007] The present Summary of the Invention is provided to introduce a series of concepts in a simplified form. These concepts are described in more detail below in the detailed description of example embodiments of the present disclosure. The Summary of the Invention is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

[0008] In some embodiments, a method of depositing a hafnium lanthanum oxide film on a substrate by a cyclic deposition process in a reaction chamber is provided. The method may include: depositing a hafnium oxide film on the substrate using at least one deposition cycle of a first sub-cycle of the cyclic deposition process, where one deposition cycle of the first sub-cycle includes: contacting the substrate with a hafnium gas precursor; and contacting the substrate with a first oxidant precursor comprising water (H2O). The method may further include: depositing a lanthanum oxide film on the substrate using at least one deposition cycle of a second sub-cycle of the cyclic deposition process, where one deposition cycle of the second sub-cycle includes: contacting the substrate with a lanthanum gas precursor; and contacting the substrate with a second oxidant precursor comprising molecular oxygen (O2).

[0009] For the purpose of summarizing the present invention and the advantages achieved over the prior art, certain objects and advantages of the present invention have been described above. Of course, it should be understood that not necessarily all such objects or advantages can be achieved in any particular embodiment of the present invention. Thus, for example, those skilled in the art will recognize that the present invention may be practiced or carried out in a manner that achieves or optimizes one advantage or a group of advantages as taught or suggested herein but does not necessarily achieve other objects or advantages as may be taught or suggested herein.

[0010] All such embodiments are intended to fall within the scope of the present invention disclosed herein. To those skilled in the art, these and other embodiments will become apparent from the following detailed description of certain embodiments with reference to the accompanying drawings, and the present invention is not limited to any particular embodiment disclosed. Brief Description of the Drawings

[0011] Although this specification concludes with claims that specifically point out and distinctly claim the subject matter regarded as embodiments of the present invention, the advantages of the embodiments of the present disclosure may be more readily determined from the description of certain examples of the embodiments of the present disclosure when read in conjunction with the accompanying drawings, in which:

[0012] Figure 1 shows a process flow diagram representing an overall super-cycle of a cyclic deposition process according to an embodiment of the present disclosure;

[0013] Figure 2 shows a process of a first sub-cycle of a cyclic deposition process according to an embodiment of the present disclosure;

[0014] Figure 3 A process showing a second sub-cycle of a cyclic deposition process according to an embodiment of the present disclosure;

[0015] Figure 4 X-ray photoelectron spectroscopy (XPS) data is shown, which demonstrates the variation of the lanthanum composition of various exemplary hafnium lanthanum oxide films with respect to the ratio of lanthanum oxide deposition sub-cycles to hafnium oxide deposition sub-cycles according to an embodiment of the present disclosure;

[0016] Figure 5 Data is shown demonstrating the crystallization temperature of various exemplary hafnium lanthanum oxide films having an increased lanthanum composition according to an embodiment of the present disclosure; and

[0017] Figure 6 Data is shown demonstrating the crystallization temperature of various exemplary hafnium lanthanum oxide films having an increased lanthanum composition (atomic %) at various film thicknesses according to an embodiment of the present disclosure. Detailed Description

[0018] Although certain embodiments and examples are disclosed below, those skilled in the art will understand that the invention extends beyond the specifically disclosed embodiments and / or uses of the invention and obvious modifications and their equivalents. Accordingly, it is intended that the scope of the invention disclosed herein should not be limited by the specific disclosed embodiments described below.

[0019] The diagrams presented herein are not intended as actual views of any particular material, structure, or device, but merely as idealized representations for describing embodiments of the present disclosure.

[0020] As used herein, the term "cyclic deposition" may refer to the sequential introduction of precursors (reactants) into a reaction chamber to deposit a film on a substrate and includes deposition techniques such as atomic layer deposition and cyclic chemical vapor deposition.

[0021] As used herein, the term "cyclic chemical vapor deposition" may refer to any process in which a substrate is sequentially exposed to two or more volatile precursors that react and / or decompose on the substrate to produce the desired deposition.

[0022] As used herein, the term "substrate" may refer to any one or more underlying materials on which a device, circuit, or film can be formed or used.

[0023] As used herein, the term "atomic layer deposition" (ALD) can refer to a vapor deposition process in which deposition cycles are carried out in a reaction chamber, preferably a plurality of consecutive deposition cycles. Generally, during each cycle, a precursor is chemisorbed onto a deposition surface (e.g., a substrate surface or the surface of a previously deposited underlying layer, such as a material from a previous ALD cycle), forming a monolayer or sub-monolayer that is not readily reactive with additional precursor (i.e., a self-limiting reaction). Thereafter, if necessary, a reactant (e.g., another precursor or a reactive gas) can subsequently be introduced into the processing chamber to convert the chemisorbed precursor into the desired material on the deposition surface. Generally, such a reactant is capable of further reacting with the precursor. In addition, during each cycle, a purge step can also be utilized to remove excess precursor and / or remove excess reactant and / or reaction by-products from the processing chamber after converting the chemisorbed precursor. Further, when carried out using alternating pulses of precursor compositions, reactive gases, and purge (e.g., inert carrier) gases, the term "atomic layer deposition" as used herein is also intended to include processes designated by related terms such as "chemical vapor atomic layer deposition", "atomic layer epitaxy" (ALE), molecular beam epitaxy (MBE), gas source MBE or organometallic MBE, and chemical beam epitaxy.

[0024] As used herein, the term "film" can refer to any continuous or discontinuous structure, material, or materials deposited by the methods disclosed herein. By way of example, a "film" can include 2D materials, nanorods, nanotubes, nanolaminates, or nanoparticles, or even partial or whole molecular layers or partial or whole atomic layers or clusters of atoms and / or molecules. A "film" can also contain one or more materials or layers having pinholes but still being at least partially continuous.

[0025] As used herein, the term "hafnium lanthanum oxide film" can refer to a film comprising a hafnium component, a lanthanum component, and an oxygen component.

[0026] As used herein, the term "sub-cycle" can refer to a cyclic deposition process that includes one or more unit cycles repeated a predetermined number of times. A combination of two or more sub-cycles can constitute an overall cyclic deposition process. Such a combination of two or more sub-cycles can be referred to as a cyclic deposition super-cycle.

[0027] As used herein, the terms "metal organic" or "organometallic" are used interchangeably and can refer to organic compounds containing metal species. Organometallic compounds can be considered a subclass of metal organic compounds having direct metal-carbon bonds.

[0028] As used herein, the terms "contact" or "exposure" are used interchangeably and can refer to the interaction between the surface of a substrate (and any deposited film) and one or more precursors or reactants.

[0029] Throughout various embodiments of the present disclosure, a variety of example materials are given. It should be noted that the chemical formulas given for each of these example materials should not be construed as limiting, and the non-limiting example materials given should not be restricted by the example stoichiometry given.

[0030] There are a wide variety of methods and related equipment for depositing high-k dielectric films on substrates such as semiconductors. Some methods form thin films on the substrate by utilizing surface reactions on the semiconductor, such as vacuum evaporation deposition, molecular beam epitaxy (MBE), different variations of chemical vapor deposition (CVD) (including low-pressure CVD, metalorganic CVD, and plasma-enhanced CVD), and atomic layer deposition (ALD).

[0031] ALD is a method of depositing a film on the surface of a substrate by sequentially introducing various precursor species. Conventional ALD equipment may include a reactor chamber, a substrate holder, a gas flow system including gas inlets for supplying precursors and reactants to the substrate surface, and an exhaust system for removing the gases used. The growth mechanism relies on the adsorption of precursors on the active sites of the substrate, and preferably conditions are maintained such that no more than a monolayer forms on the substrate, thus self-terminating the process. Exposing the substrate to a first precursor is typically followed by a purge stage or other removal process (e.g., pumping to a vacuum or "pumping out"), in which any excess amount of the first precursor and any reaction by-products are removed from the reaction chamber. Then a second reactant or precursor is introduced into the reaction chamber, where it reacts with the first precursor, and this reaction produces the desired film on the substrate. The reaction terminates when all available first precursor species adsorbed on the substrate have reacted with the second precursor. Then a second purge or other removal stage is performed, which removes any remaining second precursor and possible reaction by-products from the reaction chamber. This cycle can be repeated to grow the film to the desired thickness.

[0032] One of the recognized advantages of ALD over other deposition processes is that it is self-saturating and uniform, provided that the temperature is within the ALD window (which is above the condensation temperature of the precursor and below the thermal decomposition temperature of the precursor) and a sufficient reactant dose is provided in each pulse to saturate the surface. Thus, neither the temperature nor the gas supply need be perfectly uniform to obtain uniform deposition.

[0033] The ALD process has been used to deposit different dielectric films. Known dielectric films deposited using the ALD process can include binary oxides such as Al2O3, HfO2, ZrO2, La2O3, and Ta2O5. Ternary oxides are also materials that can be deposited by ALD and can include, for example, HfZrO, HfAlO, and HfLaO. Selecting an appropriate material for high-k dielectric applications requires consideration of the impact of the deposited material on the specific substrate and circuit environment.

[0034] In the case of ALD of hafnium lanthanum oxide, the hafnium gas-phase precursor may include, for example, hafnium tetrachloride (HfCl4), and the lanthanum gas-phase precursor may include La(THD)3. Due to the hygroscopic nature of La2O3, ozone (O3) is typically used instead of H2O as the oxidant in prior art processes. Unfortunately, both the HfCl4 / O3 process and the La(THD)3 / O3 process are highly sensitive to even small variations in the amount of ozone present. Thus, it has been difficult to achieve a reproducible process in the case of prior ALD processes.

[0035] The present disclosure thus includes methods that may be employed for depositing a hafnium lanthanum oxide film by a cyclic deposition process. The cyclic deposition process may include a cyclic deposition supercycle that includes at least a first subcycle for depositing a hafnium oxide film and a second subcycle for depositing a lanthanum oxide film. The hafnium lanthanum oxide film may be deposited by repeating the cyclic deposition supercycle one or more times such that alternating films of hafnium oxide and lanthanum oxide are deposited on a substrate. In some applications, the alternating hafnium oxide and lanthanum oxide films may be deposited to a thickness such that the resulting film includes a substantially compositionally uniform hafnium lanthanum oxide film, or alternatively includes a nanolaminated structure of hafnium lanthanum hafnium oxide films that include distinguishable alternating layers of hafnium oxide and lanthanum oxide.

[0036] The present disclosure overcomes the prior art limitations in the ALD of hafnium lanthanum oxide films by utilizing a mixed oxidant precursor, i.e., a first oxidant precursor may be utilized during a first subcycle for depositing a hafnium oxide film and a second oxidant precursor (different from the first oxidant precursor) may be utilized during a second subcycle for depositing a lanthanum oxide film.

[0037] The cyclic deposition process disclosed herein may thus deposit hafnium lanthanum oxide films having characteristics superior to those of films deposited by prior deposition processes. Additionally, the cyclic deposition process disclosed herein may deposit hafnium lanthanum oxide films in which the composition of the HfLaO x film is precisely controlled and the uniformity in the composition of the HfLaO x film is improved.

[0038] Accordingly, embodiments of the present disclosure may include methods for depositing a hafnium lanthanum oxide film on a substrate by a cyclic deposition process in a reaction chamber. In some embodiments, the cyclic deposition process may include: depositing a hafnium oxide film on the substrate using at least one deposition cycle of a first subcycle of the cyclic deposition process, wherein one deposition cycle of the first subcycle includes: contacting the substrate with a hafnium gas-phase precursor; and contacting the substrate with a first oxidant precursor that includes water (H2O). The method of the present disclosure may further include: depositing a lanthanum oxide film on the substrate using at least one deposition cycle of a second subcycle of the cyclic deposition process, wherein one deposition cycle of the second subcycle includes: contacting the substrate with a lanthanum gas-phase precursor; and contacting the substrate with a second oxidant precursor that includes molecular oxygen (O2).

[0039] Non-limiting examples of cyclic deposition processes may include atomic layer deposition (ALD), where ALD is based on generally self-limiting reactions, whereby sequential and alternating pulses of reactants are used to deposit approximately one atomic (or molecular) monolayer of material in each deposition cycle. Deposition conditions and precursors are typically selected to provide a self-saturating reaction such that an adsorbed layer of one reactant leaves a surface termination that does not react with the gaseous reactant of the same reactant. Subsequently, the substrate is contacted with a different precursor that reacts with the previous termination to effect continued deposition. Thus, each cycle of alternating pulses generally leaves no more than approximately one monolayer of the desired material. However, as mentioned above, one of ordinary skill in the art should recognize that, for example, although the process has an alternating nature, more than one monolayer of material may be deposited in one or more ALD cycles if some gas-phase reactions occur.

[0040] A cyclic deposition process for depositing a hafnium lanthanum oxide film may comprise two or more sub-cycles, where each sub-cycle may comprise an ALD-type process for depositing two or more films (e.g., a hafnium oxide film and a lanthanum oxide film). In some embodiments, the first sub-cycle may comprise an ALD-type process for depositing a hafnium oxide film, and one deposition cycle, i.e., a unit deposition cycle, may comprise exposing the substrate to a first precursor, removing any unreacted first precursor and reaction by-products from the reaction chamber, and exposing the substrate to a second precursor, followed by a second removal step. In some embodiments, the first precursor of the first sub-cycle may comprise a hafnium gas-phase precursor (“hafnium precursor”), and the second precursor of the first sub-cycle may comprise a first oxidant precursor. In some embodiments, the second sub-cycle may also comprise an ALD-type process for depositing a lanthanum oxide film, and one deposition cycle, i.e., a unit deposition cycle, may comprise exposing the substrate to a first precursor, removing any unreacted first precursor and reaction by-products from the reaction chamber, and exposing the substrate to a second precursor, followed by a second removal step. In some embodiments, the first precursor of the second sub-cycle may comprise a lanthanum gas-phase precursor (“lanthanum precursor”), and the second precursor of the second sub-cycle may comprise a second oxidant precursor.

[0041] The precursor can be separated by an inert gas such as argon (Ar) or nitrogen (N2) to prevent gas-phase reactions between precursors and to achieve self-saturating surface reactions. However, in some embodiments, the substrate can be moved to contact the first precursor and the second precursor separately. Since the reaction is self-saturating, strict temperature control of the substrate and precise dose control of the precursors may not be required. However, the substrate temperature is preferably such that the incidental gas species neither condense into a monolayer nor decompose on the surface. Before bringing the substrate into contact with the next reactive chemical, the remaining chemicals and reaction by-products (if any) are removed from the substrate surface, such as by purging the reaction space or by moving the substrate. Undesired gaseous molecules can be effectively evacuated from the reaction space by means of an inert purge gas. A vacuum pump can be used to assist the purge.

[0042] A reactor capable of depositing a hafnium lanthanum oxide film can be used for the deposition processes described herein. Such reactors include ALD reactors and CVD reactors configured to provide precursors. According to some embodiments, a showerhead reactor can be used. According to some embodiments, a crossflow, batch, semi-batch, or spatial ALD reactor can be used.

[0043] In some embodiments of the present disclosure, a batch reactor can be used. In some embodiments, a vertical batch reactor can be used. In other embodiments, the batch reactor includes a semi-batch reactor configured to accommodate 10 or fewer wafers, 8 or fewer wafers, 6 or fewer wafers, 4 or fewer wafers, or 2 or fewer wafers. In some embodiments in which a batch reactor is used, the non-uniformity between wafers is less than 3% (1σ), less than 2%, less than 1%, or even less than 0.5%.

[0044] The deposition processes described herein may optionally be performed in a reactor or reaction chamber coupled to a cluster tool. In a cluster tool, since each reaction chamber is dedicated to one type of process, the temperature of the reaction chambers in each module can be kept constant, which will increase throughput compared to a reactor where the substrate is heated to the process temperature before each run. Additionally, in a cluster tool, it is possible to shorten the time required to pump the reaction chamber to the process pressure level between substrates. In some embodiments of the present disclosure, a deposition process may be performed in a cluster tool comprising a plurality of reaction chambers, where each individual reaction chamber can be used to expose the substrate to a separate precursor gas, and the substrate can be transferred between different reaction chambers to be exposed to multiple precursor gases, and the transfer of the substrate is performed in a controlled environment to prevent oxidation / contamination of the substrate. In some embodiments of the present disclosure, a deposition process may be performed in a cluster tool comprising a plurality of reaction chambers, where each individual reaction chamber can be configured to perform an overall cyclic deposition process, i.e., different sub-cycles of a cyclic deposition super-cycle. For example, the first reaction chamber of the cluster tool can be configured to perform a first sub-cycle and the second reaction chamber of the cluster tool can be configured to perform a second sub-cycle, where the substrate can be transferred between the first reaction chamber and the second reaction chamber in a controlled environment to prevent unwanted contamination of the substrate and the oxide film thereon.

[0045] In certain embodiments, the reactor or reaction chamber may comprise a stand-alone reactor equipped with a load lock. In this case, it is not necessary to cool the reaction chamber between each run. In some embodiments, the deposition process for depositing a hafnium lanthanum oxide film may comprise a plurality of deposition cycles, i.e., a plurality of unit cycles, such as ALD cycles or cyclic CVD cycles.

[0046] In some embodiments, one or more cyclic deposition processes may be used to deposit the HfLaO of the present disclosure x film on a substrate. In some embodiments, the cyclic deposition process may comprise one or more ALD-type processes. In certain embodiments, the cyclic deposition process may comprise one or more hybrid ALD / CVD processes or one or more cyclic CVD processes. For example, in some embodiments, the growth rate of an ALD process may be low compared to a CVD process. One way to increase the growth rate can be to operate at a substrate temperature higher than that typically employed in an ALD process such that at least a portion of the deposition is provided by a chemical vapor deposition-type process, but still utilizes the sequential introduction of precursors. Such a process may be referred to as a cyclic CVD process. In some embodiments, the cyclic CVD process may comprise introducing two or more precursors into the reaction chamber, where the overlap period between the two or more precursors in the reaction chamber gives rise to both an ALD deposition component and a CVD deposition component. For example, the cyclic CVD process may comprise a continuous flow of one precursor and a periodic pulse of a second precursor into the reaction chamber.

[0047] In some embodiments, a hafnium lanthanum oxide film may be deposited using a cyclic deposition process, and non-limiting examples of such cyclic deposition processes may be referred to Figures 1 to 3 to understand, where Figure 1 an overall exemplary cyclic deposition process including a cyclic deposition supercycle is shown; Figure 2 a first exemplary subcycle for depositing a hafnium oxide film is shown; and Figure 3 a second exemplary subcycle for depositing a lanthanum oxide film is shown.

[0048] More specifically, Figure 1 an exemplary overall cyclic deposition process 100 is shown, including a cyclic deposition supercycle 150, which includes a first subcycle 120 and a second subcycle 130 for depositing a HfLaO x film. More specifically, the overall cyclic deposition process 100 may be initiated by a process 110, which includes providing a substrate into a reaction chamber and heating the substrate to a desired deposition temperature.

[0049] In some embodiments of the present disclosure, the substrate may include a planar substrate or a patterned substrate, and the patterned substrate includes high aspect ratio features such as trench structures and / or fin structures. The substrate may include one or more materials, including but not limited to silicon (Si), germanium (Ge), germanium tin (GeSn), silicon germanium (SiGe), silicon germanium tin (SiGeSn), silicon carbide (SiC), or III-V semiconductor materials such as gallium arsenide (GaAs), gallium phosphide (GaP), or gallium nitride (GaN). In some embodiments of the present disclosure, the substrate may include an engineered substrate, where a surface semiconductor layer is disposed above a bulk support, with an intervening buried oxide (BOX) disposed therebetween.

[0050] The patterned substrate may include a substrate that may include semiconductor device structures formed in or on the surface of the substrate. For example, the patterned substrate may include partially fabricated semiconductor device structures such as transistors and / or memory elements. In some embodiments, the substrate may include a single crystal surface and / or one or more subsurfaces, and the subsurfaces may include non-single crystal surfaces such as polycrystalline surfaces and / or amorphous surfaces. The single crystal surface may include, for example, one or more of the following: silicon (Si), silicon germanium (SiGe), germanium tin (GeSn), or germanium (Ge). The polycrystalline or amorphous surface may include dielectric materials such as oxides, oxynitrides, or nitrides, such as silicon oxide and silicon nitride.

[0051] The reaction chamber for deposition can be any of an atomic layer deposition reaction chamber, a chemical vapor deposition reaction chamber, or a reaction chamber as previously described herein. In some embodiments of the present disclosure, the substrate can be heated to the deposition temperature required during the cyclic deposition process. For example, the substrate can be heated to a substrate temperature below about 750 °C, or below about 650 °C, or below about 550 °C, or below about 450 °C, or below about 350 °C, or below about 300 °C, or below about 250 °C, or even below about 150 °C. In some embodiments of the present disclosure, the substrate temperature during the cyclic deposition process can be between 100 °C and 400 °C, or between 150 °C and 350 °C, or between 200 °C and 300 °C.

[0052] After heating the substrate to the required deposition temperature, Figure 1 the exemplary cyclic deposition process 100 can continue with a cyclic deposition supercycle 150, which includes one or more repetitions of depositing a hafnium oxide film using at least one deposition cycle of a first subcycle and depositing a lanthanum oxide film using at least one deposition cycle of a second subcycle. The cyclic deposition supercycle 150 can be initiated by a process block 120, which includes depositing a hafnium oxide film using at least one deposition cycle of a first subcycle.

[0053] Figure 2 The first subcycle 120 and its constituent sub-processes are shown in more detail. For example, the first subcycle 120 can be initiated by a sub-process block 210, which includes contacting the substrate with a hafnium gas-phase reactant (“hafnium precursor”) or exposing it in the case of a hafnium gas-phase reactant.

[0054] In some embodiments, the hafnium precursor can include at least one of a hafnium halide precursor, a hafnium metal-organic precursor, or an organometallic hafnium precursor.

[0055] In some embodiments, the hafnium halide precursor can include at least one halide ion ligand, and the remaining ligands are different, such as the metal-organic or organometallic ligands described later herein. In some embodiments, the hafnium halide precursor can include one, two, three, or four halide ion ligands, such as a chloride ion ligand.

[0056] In some embodiments, the hafnium halide precursor can include at least one of hafnium chloride, hafnium iodide, or hafnium bromide. In some embodiments, hafnium chloride can include hafnium tetrachloride (HfCl4). In some embodiments, hafnium iodide can include hafnium tetraiodide (HfI4). In some embodiments, hafnium bromide can include hafnium tetrabromide (HfBr4).

[0057] In some embodiments, the hafnium metal-organic precursor can include at least one of a hafnium alkylamide precursor, a precursor containing a hafnium cyclopentadienyl ligand, or other organometallic hafnium precursors.

[0058] In some embodiments, the hafnium alkylamide precursor can be selected from the group consisting of: hafnium tetra(ethylmethylamido) (Hf(NEtMe)4), hafnium tetra(dimethylamido) (Hf(NMe2)4), or hafnium tetra(diethylamido) (Hf(NEt2)4).

[0059] In some embodiments of the present disclosure, the precursor containing a hafnium cyclopentadienyl ligand can be selected from the group consisting of: tris(alkylamido)cyclopentadienyl hafnium, such as tris(dimethylamido)cyclopentadienyl hafnium (HfCp(NMe2)3) or bis(methylcyclopentadienyl)methoxymethyl hafnium ((MeCp)2(Hf(CH)3(OCH3)), or derivatives of those precursors, such as precursors in which one or more hydrocarbons (such as alkyl groups) are attached to the cyclopentadienyl ligand of those precursors, or to other alkyl groups in the alkylamido ligand.

[0060] In some embodiments, the hafnium precursor can have the following formula:

[0061] HfL1L2L3L4

[0062] Wherein each L ligand of L1 to L4 can be independently selected as:

[0063] a) A halide ion, such as a chloride ion, a bromide ion, or an iodide ion;

[0064] b) An alkylamido group, such as dimethylamido (-NMe2), diethylamino (-NEt2), ethylmethylamido (-NEtMe);

[0065] c) An amidino group, such as N,N'-dimethylformamidine;

[0066] d) A guanidino group, such as N,N'-diisopropyl-2-ethylmethylamidinoguanidino;

[0067] e) A cyclopentadienyl group or derivatives thereof, such as a cyclopentadienyl group, a methylcyclopentadienyl group, or other alkyl-substituted cyclopentadienyl ligands;

[0068] f) A cycloheptadienyl or cycloheptatrienyl group, such as a cycloheptatrienyl group or a cycloheptadienyl group;

[0069] g) An alkyl group, such as a C1-C5 alkyl group, for example, a methyl group, mainly in the case of a mixed ligand precursor;

[0070] h) An alkoxy group, such as a methoxy group (-OMe), an ethoxy group (-OEt), an isopropoxy group (-O i Pr), a n-butoxy group (-OBu), or a tert-butoxy group (-O t Bu),

[0071] i) β-diketones, such as (2,2,6,6-tetramethyl-3,5-heptanedionato (thd);

[0072] j) Donor-functionalized alkoxides, such as dimethylethanolamine.

[0073] In some embodiments of the present disclosure, the hafnium precursor comprises one or more bidentate ligands bonded to Hf via nitrogen and / or oxygen atoms. In some embodiments, the hafnium precursor comprises one or more ligands bonded to Hf via nitrogen, oxygen, and / or carbon.

[0074] In some embodiments of the present disclosure, the hafnium precursor does not comprise a plasma-excited precursor, i.e., a hafnium oxide film is deposited without plasma-exciting the precursor, in other words, a hafnium oxide film is deposited in a plasma-free environment.

[0075] In some embodiments of the present disclosure, contacting the substrate with the hafnium gas-phase precursor may comprise pulsing the hafnium precursor into the reaction chamber and then contacting the hafnium precursor with the substrate for a period of between about 0.01 seconds and about 60 seconds, or between about 0.05 seconds and about 10 seconds, or between about 0.1 seconds and about 5.0 seconds. Additionally, during pulsing of the hafnium precursor, the flow rate of the hafnium precursor may be less than 2000 sccm, or less than 500 sccm, or even less than 100 sccm. Additionally, during pulsing of the hafnium precursor above the substrate, the flow rate of the hafnium precursor may range from about 1 to about 2000 sccm, or from about 5 to about 1000 sccm, or from about 10 to about 500 sccm.

[0076] Figure 2 The exemplary sub-cycle 120 may be continued by purging the reaction chamber. For example, excess hafnium precursor and reaction by-products (if any) may be removed from the substrate surface, for example, by pumping with an inert gas. In some embodiments of the present disclosure, the purging process may comprise a purging cycle in which the substrate surface is purged for a period of less than about 5.0 seconds, or less than about 3.0 seconds, or even less than about 2.0 seconds. Excess hafnium gas-phase reactants and any possible reaction by-products may be removed by a vacuum generated by a pumping system in fluid communication with the reaction chamber.

[0077] After purging the reaction chamber with a purge cycle, exemplary cyclic deposition sub-cycle 120 may continue with sub-process block 220, which includes contacting or exposing the substrate to a first oxidant precursor, and specifically contacting the substrate to a first oxidant precursor that includes water (H2O). In alternative embodiments, the first oxidant precursor includes at least one of the following: hydrogen peroxide (H2O2), ozone (O3), or oxides of nitrogen such as nitric oxide (NO), nitrous oxide (N2O), or nitrogen dioxide (NO2). In some embodiments of the present disclosure, the oxidant precursor may include an organic alcohol such as isopropyl alcohol.

[0078] In some embodiments of the present disclosure, the first oxidant precursor does not include a plasma-excited precursor, i.e., a hafnium oxide film is deposited without plasma-exciting the precursor. In other words, in certain embodiments, a hafnium oxide film is deposited in a plasma-free environment.

[0079] In some embodiments of the present disclosure, contacting the substrate with the first oxidant precursor may include pulsing the first oxidant precursor, such as water (H2O), into the reaction chamber and then contacting the substrate with the first oxidant precursor for a period between about 0.01 seconds and about 60 seconds, or between about 0.05 seconds and about 10 seconds, or between about 0.1 seconds and about 5.0 seconds. Additionally, during the pulsing of the first oxidant precursor, the flow rate of the first oxidant precursor may be less than 2000 sccm, or less than 500 sccm, or even less than 100 sccm. Additionally, during the pulsing of the first oxidant precursor above the substrate, the flow rate of the first oxidant precursor may range from about 1 to about 2000 sccm, from about 5 to about 1000 sccm, or from about 10 to about 500 sccm.

[0080] In embodiments where the first oxidant precursor includes water (H2O), the purity of the water may be characterized by its resistivity. For example, the higher the resistivity of the water, the higher the purity, and thus the incorporation of unwanted contaminants in the deposited film may be reduced. In some embodiments, the first oxidant precursor may include water (H2O) having a resistivity greater than 5 MΩ-cm, or greater than 10 MΩ-cm, or greater than 15 MΩ-cm, or even greater than 20 MΩ-cm. In some embodiments of the present disclosure, the resistivity of the water used for depositing the hafnium oxide film may be between 5 MΩ-cm and 20 MΩ-cm.

[0081] Figure 2The exemplary sub - cycle 120 can continue by purging the reaction chamber. For example, the excess first oxidant precursor and reaction by - products (if any) can be removed from the substrate surface, for example, by pumping with an inert gas. In some embodiments of the present disclosure, the purging process can include a purging cycle in which the substrate surface is purged for a period of less than about 5.0 seconds, or less than about 3.0 seconds, or even less than about 2.0 seconds. The excess first oxidant precursor (e.g., water) and any possible reaction by - products can be removed by means of a vacuum generated by a pumping system in fluid communication with the reaction chamber.

[0082] Figure 2 The sub - cycle 120 can continue by means of a sub - process block 230 that includes a decision gate that depends on the thickness of the hafnium oxide film to be deposited by the exemplary first sub - cycle 120. If the thickness of the deposited hafnium oxide film is not sufficient for subsequent process steps, then the cyclic sub - cycle 120 can return to the sub - process block 210, and the substrate can be contacted with the hafnium gas precursor (sub - process block 210) and with the first oxidant precursor (sub - process block 220). For example, a single deposition cycle of the first sub - cycle 120, i.e., a unit deposition cycle, can include: contacting the substrate with the hafnium precursor, purging the reaction chamber, contacting the substrate with water, and purging the reaction chamber again. To deposit the hafnium oxide film to the desired thickness, the sub - cycle 120 can be repeated one or more times until the hafnium oxide film of the desired thickness is deposited, at which time the exemplary first sub - cycle can exit via the sub - process block 240.

[0083] It should be understood that in some embodiments of the present disclosure, the order in which the substrate is contacted with the hafnium precursor and the first oxidant precursor can be such that the substrate first contacts the first oxidant precursor and then contacts the hafnium precursor. Additionally, in some embodiments, the cyclic deposition sub - cycle 120 can include contacting the substrate with the hafnium precursor one or more times followed by contacting the substrate with the first oxidant precursor one or more times. In some embodiments, the cyclic deposition sub - cycle 120 can include contacting the substrate with the first oxidant precursor one or more times followed by contacting the substrate with the hafnium precursor one or more times.

[0084] In some embodiments of the present disclosure, the exemplary cyclic first sub - cycle 120 causes the substrate to alternately contact the hafnium precursor and the first oxidant precursor, and the reaction between the hafnium precursor and the first oxidant precursor can deposit a hafnium oxide film above the substrate surface.

[0085] In some embodiments of the present disclosure, the exemplary cyclic deposition sub-cycle 120 may not be repeated and only a single unit cycle of the deposition process, i.e., one deposition cycle, may be performed. For example, the substrate may be contacted with a hafnium precursor and then with a first oxidant precursor to deposit a single monolayer or less than a single monolayer of a hafnium oxide film, i.e., in some embodiments, the hafnium oxide film comprises a single monolayer or less than a single monolayer. In such embodiments where one deposition cycle is used to deposit the hafnium oxide film, the thickness of the hafnium oxide film may be less than 5 angstroms, or less than 2 angstroms, or even less than 1 angstrom. In some embodiments, the hafnium oxide film may not comprise a continuous film but may comprise a plurality of discrete regions of hafnium oxide disposed over the substrate.

[0086] In some embodiments of the present disclosure, the exemplary cyclic deposition sub-cycle 120 may be repeated one or more times to deposit the hafnium oxide film to a desired thickness. In some embodiments of the present disclosure, the unit deposition cycle of the first sub-cycle 120 may comprise: contacting the substrate with a hafnium precursor, purging the reaction chamber, contacting the substrate with a first oxidant precursor, and purging the reaction chamber again. In some embodiments of the present disclosure, the unit deposition cycle of the sub-cycle 120 may be performed more than 2 times, or more than 4 times, or more than 6 times, or more than 8 times, or more than 10 times, or more than 15 times, or more than 20 times. In some embodiments, the unit deposition cycle may be repeated to deposit the hafnium oxide film to a thickness less than 3 nanometers, or less than 2 nanometers, or less than 1 nanometer, or less than 5 angstroms or even less than 2 angstroms. In some embodiments, the hafnium oxide film may not comprise a continuous film but may comprise a plurality of discrete regions of hafnium oxide disposed over the substrate.

[0087] After completion of process block 120, i.e., the first sub-cycle, the cyclic deposition super-cycle 150 ( Figure 1 ) may continue through process block 130, which comprises depositing a lanthanum oxide film using at least one deposition cycle of a second sub-cycle.

[0088] Figure 3 More particularly, the second sub-cycle 130 and its constituent sub-processes are shown, where the second sub-cycle 130 may be initiated by sub-process block 310, which comprises: contacting the substrate with a lanthanum gas-phase precursor (“lanthanum precursor”) or exposing it in the case of a lanthanum gas-phase precursor.

[0089] In some embodiments of the present disclosure, the lanthanum precursor may include an amidine-based precursor, such as lanthanum formamidine (La(FAMD)3) or lanthanum tris(N,N′-diisopropylethylamidine) (La(iPrAMD)3). In some embodiments, the lanthanum precursor may include a diketone precursor, such as (La(THD)3). In some embodiments, the lanthanum precursor may include a Cp (cyclopentadienyl)-based precursor, such as lanthanum tris(isopropyl-cyclopentadienyl) (La(iPrCp)3). In some embodiments, the lanthanum precursor may include an amide-based compound, such as lanthanum tris(bis(trimethylsilyl)amide) (La[N(SiMe3)2]3).

[0090] In some embodiments, the lanthanum precursor may include a mixed combination of the above. In other embodiments, the lanthanum precursor may include a lanthanum precursor having a bond between nitrogens, such as lanthanum amidine. The amidine compound may include delocalized electrons that cause a bond between nitrogen and lanthanum. In other embodiments, the lanthanum precursor may include a lanthanum precursor having a bond with carbon, such as cyclopentadienyl lanthanum. In such embodiments, the lanthanum precursor may include delocalized electrons, which are regarded as compounds that form a bond between carbon and lanthanum. In other embodiments, the lanthanum precursor may include a lanthanum precursor having bonds with both nitrogen and carbon, such as lanthanum amidine and cyclopentadienyl lanthanum compounds.

[0091] In some embodiments of the present disclosure, the lanthanum precursor does not include a plasma-excited precursor, that is, a lanthanum oxide film can be deposited without plasma-exciting the precursor. In other words, a lanthanum oxide film can be deposited in a plasma-free environment.

[0092] In some embodiments of the present disclosure, contacting the substrate with the lanthanum gas-phase reactant may include pulsing the lanthanum precursor into the reaction chamber and then contacting the lanthanum precursor with the substrate for a period between about 0.01 seconds and about 60 seconds, or between about 0.05 seconds and about 10 seconds, or between about 0.1 seconds and about 5.0 seconds. Additionally, during pulsing of the lanthanum precursor into the reaction chamber, the flow rate of the lanthanum precursor may be less than 2000 sccm, or less than 500 sccm, or even less than 100 sccm. Additionally, during pulsing of the lanthanum precursor into the reaction chamber and above the substrate, the flow rate of the lanthanum precursor may range from about 1 to about 2000 sccm, or from about 5 to about 1000 sccm, or from about 10 to about 500 sccm.

[0093] Figure 3The exemplary sub-cycle 130 can continue by purging the reaction chamber. For example, excess lanthanum gas-phase reactants and reaction by-products (if present) can be removed from the substrate surface, e.g., by pumping with an inert gas. In some embodiments of the present disclosure, the purging process can include a purge cycle where the substrate surface is purged for a period of less than about 5.0 seconds, or less than about 3.0 seconds, or even less than about 2.0 seconds. The excess lanthanum precursor and any possible reaction by-products can be removed by means of a vacuum generated by a pumping system in fluid communication with the reaction chamber.

[0094] After purging the reaction chamber with the purge cycle, the exemplary cycle deposition sub-cycle 130 can continue with sub-process block 320, which includes: contacting the substrate with a second oxidant precursor or exposing it in the case of a second oxidant precursor, and specifically, using a second oxidant precursor comprising molecular oxygen (O2). In alternative embodiments, the second oxidant precursor can include at least one of the following: water (H2O), hydrogen peroxide (H2O2), ozone (O3), or oxides of nitrogen, such as nitric oxide (NO), nitrous oxide (N2O), or nitrogen dioxide (NO2). In some embodiments of the present disclosure, the oxidant precursor can include an organic alcohol, such as isopropyl alcohol.

[0095] In some embodiments of the present disclosure, the second oxidant precursor, such as molecular oxygen (O2), does not include a plasma-excited precursor, i.e., a lanthanum oxide film is deposited without plasma-exciting the precursor; in other words, a lanthanum oxide film is deposited in a plasma-free environment.

[0096] In embodiments where the second oxidant precursor includes molecular oxygen (O2), a high-purity molecular oxygen (O2) source can be used to generally prevent unwanted contamination of the deposited lanthanum oxide film. Thus, in some embodiments, the purity of molecular oxygen (O2) can be greater than 99.99%, or greater than 99.999%, or greater than 99.9999%, or even greater than 99.99999%.

[0097] In some embodiments of the present disclosure, contacting the substrate with a second oxidant precursor, such as molecular oxygen (O2), can include pulsing the second oxidant precursor into the reaction chamber and then contacting the substrate with the second oxidant precursor for a period between about 0.01 seconds and about 60 seconds, or between about 0.05 seconds and about 10 seconds, or between about 0.1 seconds and about 5.0 seconds. Additionally, during pulsing the second oxidant precursor into the reaction chamber, the flow rate of the second oxidant precursor can be less than 2000 sccm, or less than 500 sccm, or even less than 100 sccm. Additionally, during pulsing the second oxidant precursor above the substrate, the flow rate of the second oxidant precursor can range from about 1 to about 2000 sccm, or about 5 to about 1000 sccm, or about 10 to about 500 sccm.

[0098] Figure 3 The exemplary sub-cycle 130 can continue by purging the reaction chamber. For example, the excess second oxidant precursor and reaction by-products (if any) can be removed from the substrate surface, for example, by pumping with an inert gas. In some embodiments of the present disclosure, the purge process can include a purge cycle in which the substrate surface is purged for a period of less than about 5.0 seconds, or less than about 3.0 seconds, or even less than about 2.0 seconds. The excess second oxidant precursor and any possible reaction by-products can be removed by means of a vacuum generated by a pumping system in fluid communication with the reaction chamber.

[0099] Figure 3 The sub-cycle 130 can continue through a sub-process block 330 that includes a decision gate that depends on the thickness of the lanthanum oxide film to be deposited by the exemplary second sub-cycle 130. If the thickness of the deposited lanthanum oxide film is not sufficient for subsequent process steps, then the cyclic sub-cycle 130 can return to the sub-process block 310, and the substrate can be contacted with the lanthanum precursor (sub-process block 310) and with the second oxidant precursor, such as molecular oxygen (O2) (sub-process block 320). For example, a single deposition cycle of the second sub-cycle 130, i.e., a unit deposition cycle, can include: contacting the substrate with a gaseous lanthanum reactant, purging the reaction chamber, contacting the substrate with the second oxidant precursor, and purging the reaction chamber again. To deposit the lanthanum oxide film to the desired thickness, the sub-cycle 130 can be repeated one or more times until the desired thickness of the lanthanum oxide film is deposited on the substrate, at which time the exemplary second sub-cycle 130 can exit through the sub-process block 340.

[0100] It should be understood that in some embodiments of the present disclosure, the order in which the substrate is contacted with the lanthanum precursor and the second oxidant precursor can be such that the substrate is first contacted with the second oxidant precursor and then with the lanthanum precursor. Additionally, in some embodiments, the cyclic deposition of the second sub-cycle 130 can include contacting the substrate with the lanthanum precursor one or more times, followed by contacting the substrate with the second oxidant precursor one or more times. In some embodiments, the cyclic deposition of the second sub-cycle 130 can include contacting the substrate with the second oxidant precursor one or more times, followed by contacting the substrate with the lanthanum precursor one or more times.

[0101] In some embodiments of the present disclosure, the exemplary cyclic sub-cycle 130 alternately contacts the substrate with the lanthanum precursor and the second oxidant precursor, and the reaction between the lanthanum precursor and the second oxidant precursor can deposit a lanthanum oxide film over the substrate.

[0102] In some embodiments of the present disclosure, the exemplary cyclic deposition sub-cycle 130 may not be repeated and only a single unit cycle of the deposition process, i.e., one deposition cycle, may be performed. For example, the substrate may be contacted with a lanthanum precursor and then with a second oxidant precursor to deposit a single monolayer or less than a single monolayer of the lanthanum oxide film, i.e., in some embodiments, the lanthanum oxide film comprises a single monolayer or less than a single monolayer. In such embodiments where one deposition cycle is used to deposit the lanthanum oxide film, the thickness of the lanthanum oxide film may be less than 5 angstroms, or less than 2 angstroms, or even less than 1 angstrom. In some embodiments, the lanthanum oxide film may not comprise a continuous film but may comprise multiple discrete regions of lanthanum oxide disposed over the substrate.

[0103] In some embodiments of the present disclosure, the exemplary cyclic deposition sub-cycle 130 may be repeated one or more times to deposit the lanthanum oxide film to a desired thickness. In some embodiments of the present disclosure, the unit deposition cycle of the second sub-cycle 130 may comprise: contacting the substrate with a lanthanum precursor, purging the reaction chamber, contacting the substrate with a second oxidant precursor, and purging the reaction chamber again. In some embodiments of the present disclosure, the unit deposition cycle of the sub-cycle 130 may be performed more than 2 times, or more than 4 times, or more than 6 times, or more than 8 times, or more than 10 times, or more than 15 times, or more than 20 times or even more. In some embodiments, the unit deposition cycle may be repeated to deposit the lanthanum oxide film to a thickness less than 3 nanometers, or less than 2 nanometers, or less than 1 nanometer, or less than 5 angstroms or even less than 2 angstroms. In some embodiments, the lanthanum oxide film may not comprise a continuous film but may comprise multiple discrete regions of lanthanum oxide disposed over the substrate.

[0104] After completion of the second sub-cycle 130, Figure 1 the exemplary cyclic deposition process 100 may continue via a process block 140 that includes a decision gate, where the decision gate depends on the total thickness of the hafnium lanthanum oxide film deposited by the first and second sub-cycles. If the total thickness of the hafnium lanthanum oxide film is not sufficient for the desired semiconductor device application, the cyclic deposition super-cycle 150 may be repeated by returning to process block 120 and depositing a hafnium oxide film using at least one deposition cycle of the first sub-cycle, and then using process block 130 to deposit a lanthanum oxide film using at least one deposition cycle of the second sub-cycle, thereby depositing alternating layers of hafnium oxide and lanthanum oxide. Thus, the cyclic deposition super-cycle 150 may be repeated one or more times until a hafnium lanthanum oxide film of the desired thickness is deposited over the substrate. Once the desired thickness of the hafnium lanthanum oxide film is achieved, the exemplary cyclic deposition process 100 may exit via process block 160, and the substrate with the hafnium lanthanum oxide film disposed thereon may undergo additional semiconductor device manufacturing processes.

[0105] It should be understood that in some embodiments of the present disclosure, the order of depositing the hafnium oxide film and the lanthanum oxide film on the substrate may be such that the cyclic deposition supercycle 150 includes first depositing the lanthanum oxide film, then depositing the hafnium oxide film, and then, if necessary, repeating the lanthanum oxide deposition and hafnium oxide deposition steps to cause the deposition of the hafnium lanthanum oxide film.

[0106] In some embodiments of the present disclosure, the method of depositing the hafnium lanthanum oxide film includes deposition processes for depositing the hafnium oxide film or component (e.g., one or more first subcycles) and depositing the lanthanum oxide film or component (e.g., one or more second subcycles). For example, the method of depositing the hafnium lanthanum oxide film covered by the present disclosure may include a plurality of supercycles 150, which include one or more hafnium oxide (HfO x ) deposition subcycles and one or more lanthanum oxide (LaO x ) deposition subcycles.

[0107] In some embodiments, certain properties of the deposited hafnium lanthanum oxide film can be controlled by varying the ratio of the number of first subcycles (HfO x subcycles) performed in an individual supercycle to the number of second subcycles (LaO x subcycles) performed. In other words, the exemplary cyclic deposition process 100 can include the ratio of the first subcycles performed per unit supercycle to the second subcycles performed. Alternatively, the exemplary cyclic deposition process 100 can include the ratio of the second subcycles performed per unit supercycle to the first subcycles performed. In some embodiments, the ratio of the second subcycles (LaO x subcycles) performed per supercycle to the first subcycles (HfO x subcycles) performed is less than 0.50, or less than 0.40, or less than 0.30, or less than 0.20, or less than 0.15, or less than 0.10, or even less than 0.05.

[0108] In some embodiments, within a given supercycle or between consecutive supercycles, one or more deposition parameters of the first subcycle (LaO x subcycles) can be different from one or more deposition parameters of another first subcycle (LaO x subcycles). In some embodiments, within a given supercycle or between consecutive supercycles, one or more deposition parameters of the second subcycle (HfO x subcycles) can be different from one or more deposition parameters of another second subcycle (HfO x subcycles). In some embodiments, throughout the deposition process, i.e., in one or more consecutive supercycles, the deposition parameters of the first subcycle or the second subcycle can be substantially the same.

[0109] In some embodiments of the present disclosure, the ratio of the second sub - cycles (LaO x sub - cycles) to the first sub - cycles (HfO x sub - cycles) executed per super - cycle can be used to control the composition of the hafnium - lanthanum oxide film, such as the lanthanum composition (atomic %) in the hafnium - lanthanum oxide film. More specifically, Figure 4 X - ray photoelectron spectroscopy (XPS) data is shown, which shows the variation of the lanthanum composition (atomic %) of various exemplary hafnium - lanthanum oxide films with respect to the ratio of lanthanum oxide deposition sub - cycles to hafnium oxide deposition sub - cycles, according to embodiments of the present disclosure. Examination of Figure 4 shows a clear relationship between the LaO x :HfO x sub - cycle ratio and the lanthanum composition (atomic %) present in the exemplary HfLaO x film. For example, as the LaO x :HfO x sub - cycle ratio decreases, the lanthanum composition in the exemplary HfLaO x film also decreases. Embodiments of the present disclosure can thus provide a method for tightly controlling the composition of the deposited hafnium - lanthanum oxide film. For example, the lanthanum composition of the hafnium - lanthanum oxide film deposited according to embodiments of the present disclosure can be less than 10 atomic %, or less than 7 atomic %, or less than 5 atomic %, or less than 3 atomic %, or less than 2 atomic %, or even equal to or less than 1 atomic %. In some embodiments, the lanthanum composition in the hafnium - lanthanum oxide film deposited according to embodiments of the present disclosure can be between 0.5 atomic % and 3 atomic %, or between 1.0 atomic % and 2.5 atomic %.

[0110] In some embodiments of the present disclosure, a hafnium - lanthanum oxide film can be deposited with a low concentration of impurities. For example, a hafnium - lanthanum oxide film can be deposited where the impurity concentration is less than 10 atomic %, or less than 5 atomic %, or less than 2 atomic %, or less than 1 atomic %, or less than 0.5 atomic %, or even less than 0.2 atomic %. In some embodiments, the impurities in the hafnium - lanthanum oxide film can include, but are not limited to, carbon. For example, a hafnium - lanthanum oxide film can be deposited where the carbon concentration is less than 10 atomic %, or less than 5 atomic %, or less than 2 atomic %, or less than 1 atomic %, or less than 0.5 atomic %, or even less than 0.2 atomic %.

[0111] In some embodiments, the method of the present disclosure can deposit a hafnium lanthanum oxide film with greater compositional uniformity due to a reduction in the hygroscopicity of the deposition process achieved by using two different oxidant precursors for the hafnium oxide deposition sub-cycle and the lanthanum oxide deposition sub-cycle. In some embodiments of the present disclosure, the lanthanum compositional uniformity in the hafnium lanthanum oxide film deposited according to the embodiments of the present disclosure can be less than 2 atomic % (1-σ), or less than 0.5 atomic % (1-σ), or less than 0.2 atomic % (1-σ), or less than 0.1 atomic % (1-σ). In some embodiments of the present disclosure, the lanthanum compositional uniformity in the hafnium lanthanum oxide film deposited according to the embodiments of the present disclosure can be between 2 atomic % (1-σ) and 0.1 atomic % (1-σ). In the embodiments disclosed herein, the atomic concentration of an element can be determined using Rutherford backscattering (RBS) or x-ray photoelectron spectroscopy (XPS).

[0112] In some embodiments, the hafnium lanthanum oxide deposited according to the method disclosed herein can include a nanolaminated film. That is, in some embodiments, separate and distinct layers may be visible within the hafnium lanthanum oxide film. For example, the hafnium lanthanum oxide film can include a nanolaminate that includes alternating layers of hafnium oxide and lanthanum oxide.

[0113] In some embodiments, the hafnium lanthanum oxide deposited according to the method disclosed herein is not a nanolaminated film. That is, in some embodiments, separate and distinct layers may not be visible within the hafnium lanthanum oxide film deposited according to the embodiments of the present disclosure. For example, a uniform or substantially compositionally uniform hafnium lanthanum oxide film can be deposited by the method disclosed herein. In some embodiments, the hafnium lanthanum oxide film includes a substantially compositionally uniform ternary hafnium lanthanum oxide film.

[0114] More specifically, in some embodiments of the present disclosure, the hafnium lanthanum oxide film deposited by the cyclic deposition process described herein can include a substantially compositionally uniform hafnium lanthanum oxide film. For example, the cyclic deposition process described herein can alternately deposit a hafnium oxide film and a lanthanum oxide film (or vice versa). However, since in some embodiments, the hafnium oxide film and the lanthanum oxide film can be deposited to a thickness of less than 5 angstroms, the alternating layers can diffuse in the middle, resulting in a substantially compositionally uniform hafnium lanthanum oxide film, that is, there is no distinguishable difference in the hafnium lanthanum oxide film between the hafnium oxide region and the lanthanum oxide region.

[0115] In some embodiments, the hafnium lanthanum oxide film of the present disclosure can be deposited to a thickness of 20 nanometers to 0.5 nanometers, or 15 nanometers to 1 nanometer, or 10 nanometers to 1.5 nanometers. In some embodiments, the hafnium lanthanum oxide film of the present disclosure can be deposited to a thickness of less than 20 nanometers, or less than 15 nanometers, or less than 10 nanometers, or less than 8 nanometers, or even less than 5 nanometers.

[0116] In some embodiments of the present disclosure, the growth rate of the hafnium lanthanum oxide film can be / cycle to about / cycle, or / cycle to / cycle, or / cycle to / cycle. In some embodiments, the growth rate of the hafnium lanthanum oxide film is greater than / cycle, or greater than / cycle, or greater than / cycle or greater than / cycle, or greater than / cycle. In some embodiments, the growth rate of the hafnium lanthanum oxide film is less than / cycle, or less than / cycle, or less than / cycle, or less than / cycle, or less than / cycle. The growth rates described herein are based on both combined HfO x and LaO x subcycles, i.e., a cycle means an HfO x or LaO x subcycle.

[0117] The hafnium lanthanum oxide film deposited by the cyclic deposition process disclosed herein can be a continuous film. In some embodiments, the hafnium lanthanum oxide film can be continuous at a thickness of 100 nanometers or less, or 60 nanometers or less, or 50 nanometers or less, or 40 nanometers or less, or 30 nanometers or less, or 20 nanometers or less, or 10 nanometers or less, or 5 nanometers or less, or 2 nanometers or less, or 1 nanometer or less, or even 0.5 nanometer or less. The continuity mentioned herein can be physical continuity or electrical continuity. In some embodiments of the present disclosure, the thickness at which the hafnium lanthanum oxide film can be physically continuous can be different from the thickness at which the film is electrically continuous, and vice versa.

[0118] In some embodiments of the present disclosure, the hafnium lanthanum oxide film can be deposited on a substrate comprising high aspect ratio features, such as a three-dimensional non-planar substrate. In some embodiments, the hafnium lanthanum oxide film can be deposited over a substrate comprising one or more trench structures and / or fin structures having an aspect ratio (height / width) greater than 10:1, or greater than 20:1, or greater than 30:1, or even greater than 50:1. In such embodiments in which the hafnium lanthanum oxide film is deposited over a substrate comprising high aspect ratio features, the step coverage of the deposited film can be greater than about 90%, or greater than about 95%, or greater than about 99%, or even substantially equal to 100%.

[0119] In some embodiments of the present disclosure, hafnium lanthanum oxide films deposited according to the embodiments of the present disclosure may undergo one or more post-deposition processes to further improve the quality of the films, for example, to increase crystallinity or densify the films. Thus, in some embodiments, the method of the present disclosure may further include thermally annealing the hafnium lanthanum oxide film after deposition. For example, the hafnium lanthanum oxide film may be thermally annealed at a temperature below 800 °C, or below 700 °C, or below 600 °C, or below 500 °C or below 400 °C or even below 300 °C, or in a temperature range between 300 °C and 800 °C, or between 350 °C and 750 °C or between 400 °C and 600 °C.

[0120] In some embodiments of the present disclosure, post-deposition thermal annealing of the hafnium lanthanum oxide film may be performed in a reaction chamber under a controlled environment. For example, thermal annealing of the hafnium lanthanum oxide film may be performed in an inert gas atmosphere, such as a noble gas (e.g., Ar, He, etc.) or nitrogen. In additional examples, thermal annealing of the hafnium lanthanum oxide film may be performed in a hydrogen-containing environment, such as a nitrogen-hydrogen mixed gas (forming gas) (H2 / N2). In further examples, thermal annealing of the hafnium lanthanum oxide film may be performed in an oxygen-containing environment, such as molecular oxygen (O2), water (H2O), ozone (O3) or hydrogen peroxide (H2O2).

[0121] In some embodiments of the present disclosure, thermally annealing the hafnium lanthanum oxide film after deposition further includes at least partially crystallizing the hafnium lanthanum oxide film. In some embodiments, thermally annealing the hafnium lanthanum oxide film after deposition may form a hafnium lanthanum oxide film that includes a predominantly orthorhombic crystal structure. In some embodiments, thermally annealing the hafnium lanthanum oxide film after deposition further includes forming a substantially single-crystalline hafnium lanthanum oxide film. In some embodiments, the substantially single-crystalline hafnium lanthanum oxide film includes a predominantly orthorhombic crystal structure. In some embodiments of the present disclosure, the hafnium lanthanum oxide film may be deposited in an amorphous state, and thermally annealing the hafnium lanthanum oxide film may provide controlled crystallization of the LaHfO x film.

[0122] Figure 5 Exemplary data showing the crystallization temperatures of various exemplary hafnium lanthanum oxide films deposited according to the embodiments of the present disclosure at various deposition temperatures and with increasing lanthanum composition (atomic %). Examination of Figure 5 showed that the crystallization temperature of the exemplary hafnium lanthanum oxide films decreased as the lanthanum composition (atomic %) in the exemplary hafnium lanthanum oxide films decreased. As a non-limiting example, the hafnium lanthanum oxide film may include a lanthanum composition equal to or less than 1 atomic %, wherein the crystallization temperature is below 600 °C. As another non-limiting example, the hafnium lanthanum oxide film may include a lanthanum composition equal to or less than 1 atomic %, wherein the crystallization temperature is below approximately 450 °C.

[0123] For Figure 5 Further examination of Figure 5 shows that, generally, the crystallization temperature of exemplary hafnium lanthanum oxide films decreases as the deposition temperature of the hafnium lanthanum oxide films increases. As a non-limiting example, the hafnium lanthanum oxide film may include a lanthanum component of equal to or less than 1 atomic % deposited at a deposition temperature below 200 °C and a corresponding crystallization temperature below 650 °C, or below 600 °C, or below 550 °C, or between 550 °C and 650 °C. As another non-limiting example, the hafnium lanthanum oxide film may include a lanthanum concentration of equal to or less than 1 atomic % deposited at a deposition temperature below 300 °C and a corresponding crystallization temperature below 550 °C, or below 500 °C, or below 450 °C, or between 450 °C and 550 °C.

[0124] Figure 6 Exemplary data showing the crystallization temperature of various exemplary hafnium lanthanum oxide films as the lanthanum component (atomic %) increases at various film thicknesses is presented. For Figure 6 examination of Figure 6 shows that, generally, the crystallization temperature decreases as the lanthanum content in the hafnium lanthanum oxide film decreases, as previously shown. For Figure 6 further examination of Figure 6 shows that the crystallization temperature also decreases as the thickness of the hafnium lanthanum oxide film increases. For example, in some embodiments, the hafnium lanthanum oxide film may have a lanthanum component between approximately 1.5 atomic % and 3 atomic %, wherein the corresponding crystallization temperature is between approximately 540 °C and 680 °C. In some embodiments, the hafnium lanthanum oxide film may have a lanthanum component of less than 1.5 atomic %, a film thickness of less than 3 nm, and a crystallization temperature below 650 °C. In some embodiments, the hafnium lanthanum oxide film may have a lanthanum component of less than 1.5 atomic %, a film thickness of less than 5 nm, and a crystallization temperature below 600 °C. In some embodiments, the hafnium lanthanum oxide film may have a lanthanum component of less than 1.5 atomic %, a film thickness of less than 7 nm, and a crystallization temperature below 560 °C. In some embodiments, the hafnium lanthanum oxide film may have a lanthanum component of less than 1.5 atomic %, a film thickness of less than 10 nm, and a crystallization temperature below 550 °C.

[0125] The example embodiments of the present disclosure described above do not limit the scope of the present invention because these embodiments are merely examples of embodiments of the present invention, which is defined by the appended claims and their legal equivalents. Any equivalent embodiments are intended to be within the scope of the present invention. Indeed, those skilled in the art will appreciate from the specification various modifications to the present disclosure other than those shown and described herein, such as alternative applicable combinations of the described elements. Such modifications and embodiments are also intended to be within the scope of the appended claims.

Claims

1. A method for depositing a hafnium lanthanum oxide film on a substrate, which is carried out by a cyclic deposition process in a reaction chamber, the method comprising: Depositing a hafnium oxide film on the substrate using at least one deposition cycle of a first sub-cycle of the cyclic deposition process, wherein at least one deposition cycle of the first sub-cycle comprises: Bringing the substrate into contact with a hafnium gas-phase precursor; and Bringing the substrate into contact with a first oxidant precursor containing water (H2O), wherein the first oxidant precursor contains water with a resistivity greater than 5 MΩ-cm; Depositing a lanthanum oxide film on the substrate using at least one deposition cycle of a second sub-cycle of the cyclic deposition process, wherein at least one deposition cycle of the second sub-cycle comprises: Bringing the substrate into contact with a lanthanum gas-phase precursor; and Bringing the substrate into contact with a second oxidant precursor containing molecular oxygen (O2).

2. The method according to claim 1, wherein the hafnium gas-phase precursor comprises at least one of a hafnium halide precursor or a hafnium metal-organic precursor.

3. The method according to claim 2, wherein the hafnium halide precursor comprises at least one of hafnium tetrachloride (HfCl4), hafnium tetraiodide (HfI4), or hafnium tetrabromide (HfBr4).

4. The method according to claim 2, wherein the hafnium metal-organic precursor comprises at least one of the following: hafnium tetrakis(ethylmethylamido) (Hf(NEtMe)4), hafnium tetrakis(dimethylamido) (Hf(NMe2)4), hafnium tetrakis(diethylamido) (Hf(NEt2)4), hafnium tris(dimethylamido)cyclopentadienyl (HfCp(NMe2)3), or bis(methylcyclopentadienyl)methoxymethylhafnium ((MeCp)2Hf(CH)3(OCH3)).

5. The method according to claim 1, wherein the lanthanum gas-phase precursor comprises at least one of an amidinato lanthanum or a cyclopentadienyl lanthanum compound.

6. The method according to claim 1, wherein before depositing the hafnium oxide film on the substrate, the substrate is heated to a temperature of 100 °C to 400 °C.

7. The method according to claim 1, wherein the lanthanum composition homogeneity in the hafnium lanthanum oxide film is less than 2 atomic % (1-σ).

8. The method according to claim 1, wherein the hafnium lanthanum oxide film has a lanthanum composition of less than 10 atomic %.

9. The method according to claim 8, wherein the hafnium lanthanum oxide film has a lanthanum composition of equal to or less than 1 atomic %.

10. The method according to claim 1, wherein the thickness of the hafnium lanthanum oxide film is less than 20 nanometers.

11. The method according to claim 10, wherein the thickness of the hafnium lanthanum oxide film is between 3 nanometers and 10 nanometers.

12. The method according to claim 1, wherein the second oxidant precursor comprises molecular oxygen (O2) with a purity greater than 99.999%.

13. The method according to claim 1, wherein the hafnium oxide film is deposited to a thickness of less than 3 nanometers.

14. The method according to claim 1, wherein the lanthanum oxide film is deposited to a thickness of less than 3 nanometers.

15. The method according to claim 1, wherein the hafnium lanthanum oxide film comprises a ternary hafnium lanthanum oxide film.

16. The method according to claim 1, wherein the hafnium lanthanum oxide film comprises a nanolaminate.

17. The method according to claim 1, wherein the cyclic deposition process comprises varying the ratio of the number of first sub-cycles performed to the number of second sub-cycles performed, and wherein the ratio of the second sub-cycles to the first sub-cycles performed per super-cycle is less than 0.

2.

18. The method according to claim 17, wherein the cyclic deposition process comprises a ratio of the second sub-cycles to the first sub-cycles performed that is less than 0.

1.

19. The method according to claim 1, wherein the hafnium lanthanum oxide film comprises a carbon content of less than 2 atomic %.

20. The method according to claim 1, further comprising thermally annealing the hafnium lanthanum oxide film after depositing the hafnium lanthanum oxide film.

21. The method according to claim 20, wherein the hafnium lanthanum oxide film is thermally annealed at a temperature below 800 °C.

22. The method according to claim 20, wherein thermally annealing the hafnium lanthanum oxide film further comprises at least partially crystallizing the hafnium lanthanum oxide film.

23. The method according to claim 22, wherein the hafnium lanthanum oxide film comprises a lanthanum component of equal to or less than 1 atomic %, and wherein the crystallization temperature is below 600 °C.

24. The method according to claim 22, wherein the hafnium lanthanum oxide film comprises a lanthanum component of equal to or less than 1 atomic %, and wherein the crystallization temperature is below 450 °C.

25. The method according to claim 22, wherein the at least partially crystallized hafnium lanthanum oxide film comprises a predominantly orthorhombic crystal structure.

26. The method according to claim 1, wherein the first sub-cycle and the second sub-cycle comprise an atomic layer deposition process.

27. The method according to claim 1, wherein the cyclic deposition process comprises one or more repeated super-cycles, each super-cycle including depositing the hafnium oxide film on the substrate and depositing the lanthanum oxide film on the substrate.

28. The method according to claim 27, wherein within a unit super-cycle, the second sub-cycle is performed before the first sub-cycle.

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