Low-temperature growth of transition metal chalcogenides

Abstract

Transition metal dichalcogenide films and methods for depositing transition metal dichalcogenide films on a substrate are described. Methods for converting transition metal oxide films to transition metal dichalcogenide films are also described. The substrate is exposed to a precursor and a chalcogenide reactant to form the transition metal dichalcogenide film. The exposure can be sequential or simultaneous.

Description

Technical Field

[0001]

[0001] Embodiments of the present disclosure generally relate to methods of forming transition metal dichalcogenides (TMDCs). In particular, embodiments of the present disclosure are directed to methods of forming TMDC films for memory and logic applications.

Background Art

[0002]

[0002] The semiconductor processing industry continues to strive for higher production yields while increasing the uniformity of layers deposited on substrates having larger surface areas. The combination of these same elements with new materials results in higher circuit integration per unit area of the substrate. As the circuit integration increases, the need for uniformity and process control with respect to the layer thickness increases. As a result, various techniques have been developed for depositing layers on substrates in a cost-effective manner while maintaining control of the layer properties.

[0003]

[0003] Chemical vapor deposition (CVD) is one of the most common deposition processes used to deposit layers on substrates. CVD is a flux-dependent deposition technique, and precise control of the substrate temperature and the precursors introduced into the processing chamber is required to produce a desired layer of uniform thickness. These requirements become more important as the substrate size increases, creating a need for more complex chamber designs and gas flow techniques to maintain appropriate uniformity.

[0004]

[0004] One type of CVD that exhibits excellent step coverage is cyclic deposition or atomic layer deposition (ALD). Cyclic deposition is based on atomic layer epitaxy (ALE) and uses chemisorption techniques to supply precursor molecules onto the substrate surface in sequential cycles. This cycle exposes the substrate surface to a first precursor, a purge gas, a second precursor, and a purge gas. The first and second precursors react to form a product compound as a film on the substrate surface. This cycle is repeated to form a layer of the desired thickness.

[0005]

[0005] The increasing complexity of advanced microelectronic devices places demanding requirements on currently used deposition technologies. Unfortunately, the number of viable chemical precursors available that possess the essential properties of robust thermal stability, high reactivity, and vapor pressure suitable for film growth is limited.

[0006]

[0006] Transition metal dichalcogenides (TMDCs) are known to be promising candidates for mitigating metal migration problems associated with the miniaturization of film wiring. Furthermore, TMDCs offer superior conductivity and carrier mobility compared to current processes for 3D NAND devices. Recent TMDC methods require high-temperature processes, which may be incompatible with the thermal history of the device.

[0007]

[0007] Therefore, in the art there is a need for TMDCs that can be grown at lower temperatures, which are suitable for the integration of devices in temperature-sensitive structures. [Overview of the project]

[0008]

[0008] One or more embodiments of the present disclosure relate to a method for depositing a film, including forming a transition metal oxide film on a substrate surface, and converting the transition metal oxide film into a transition metal dichalcogenide film.

[0009]

[0009] Additional embodiments of the disclosure relate to a method for depositing a film, comprising forming a transition metal dichalcogenide film in a process cycle including a transition metal oxide precursor on a substrate, a purge gas, a chalcogenide reactant, and sequential exposure to the purge gas.

[0010]

[0010] Further embodiments of the disclosure relate to a method for depositing a film, including forming a transition metal oxide film in a metal oxide process cycle including sequential exposure of a substrate to a transition metal precursor, a purge gas, oxide reactants, and a purge gas, and for converting a transition metal oxide film to a transition metal dichalcogenide film in a chalcogen process cycle including sequential exposure of the transition metal oxide film to chalcogenide reactants and a purge gas.

[0011]

[0011] To allow for a more detailed understanding of the features of the above disclosure, a more specific description of the disclosure, which has been briefly summarized above, is provided with reference to embodiments, some of which are shown in the additional drawings. However, it should be noted that the accompanying drawings only show typical embodiments of the present disclosure and should therefore not be considered to limit its scope. [Brief explanation of the drawing]

[0012] [Figure 1]

[0012] A cross-sectional view of a substrate according to one or more embodiments of the disclosure is shown. [Figure 2]

[0013] The diagram shows a cross-sectional view of a substrate according to one or more embodiments of the diagram. [Figure 3]

[0014] A process flow diagram of the method is shown according to one or more embodiments of the disclosure. [Modes for carrying out the invention]

[0013]

[0015] Before describing some exemplary embodiments of this disclosure, it should be understood that this disclosure is not limited to the configuration or process step details described below. Other embodiments of this disclosure are possible and can be implemented or performed in various ways.

[0014]

[0016] As used in this specification and the attached claims, the term “substrate” refers to the surface or portion of a surface on which the process acts. Unless the context clearly indicates otherwise, it will also be understood by those skilled in the art that a reference to a substrate may also refer only to a portion of a substrate. Furthermore, a reference to deposition on a substrate may mean both a bare substrate and a substrate having one or more films or features deposited or formed thereon.

[0015]

[0017] As used herein, the term “substantially absent” means that in a transition metal dichalcogenide film, there is less than 5% oxygen present, including less than 4%, less than 3%, less than 2%, less than 1%, and less than 0.5% on an atomic basis.

[0016]

[0018] As used herein, “substrate” refers to any substrate or material surface formed on a substrate on which a film treatment is performed during the manufacturing process. For example, substrate surfaces on which treatment can be performed include, depending on the application, materials such as silicon, silicon oxide, strained silicon, silicon-on-insulator (SOI), carbon-doped silicon oxide, amorphous silicon, doped silicon, germanium, gallium arsenide, glass, sapphire, and any other materials such as metals, metal nitrides, metal alloys, and other conductive materials. Substrates include, but are not limited to, semiconductor wafers. Substrates can be exposed to pretreatment processes to polish, etch, reduce, oxidize, hydroxylate, anneal, UV cure, electron beam cure, and / or bake the substrate surface. In addition to direct film treatment on the surface of the substrate itself, any of the film treatment steps disclosed herein may be performed on an underlying layer formed on the substrate, as disclosed in more detail below, and the term “substrate surface” is intended to include such underlying layers as indicated in the context. Therefore, for example, when a film / layer or partial film / layer is deposited on the substrate surface, the exposed surface of the newly deposited film / layer becomes the substrate surface.

[0017]

[0019] As used herein, “substrate surface” means a substrate surface on which layers may be formed. A substrate surface may have one or more features formed therein, one or more layers formed thereon, and combinations thereof. The substrate (or substrate surface) may be pretreated before the deposition of the transition metal dichalcogenide layer by, for example, polishing, etching, reduction, oxidation, halogenation, hydroxide, annealing, baking, etc.

[0018]

[0020] The substrate can be any substrate on which material can be deposited, such as a silicon substrate, a III-V compound substrate, a silicon germanium (SiGe) substrate, an epitaxial substrate, a silicon-on-insulator (SOI) substrate, a display substrate such as a liquid crystal display (LCD), a plasma display, an electroluminescent (EL) lamp display, a solar array, a solar panel, a light-emitting diode (LED) substrate, or a semiconductor wafer. In some embodiments, one or more additional layers may be placed on the substrate such that a transition metal dichalcogenide layer may be formed thereon. For example, in some embodiments, a layer containing a metal, a nitride, an oxide, or a combination thereof may be placed on the substrate, and a transition metal dichalcogenide layer may be formed on such a layer.

[0019]

[0021] In one or more embodiments, the term “on” a film or layer of film includes a film or layer that is directly on a surface, e.g., a substrate surface, and there is one or more underlying layers between the film or layer and the surface, e.g., the substrate surface. Thus, in one or more embodiments, the expression “on the substrate surface” is intended to include one or more underlying layers. In other embodiments, the expression “directly on” refers to a layer or film that is in contact with a surface, e.g., a substrate surface, without an intervening layer. Thus, the expression “layer on the substrate surface” refers to a layer that is in direct contact with the substrate surface without any intervening layers.

[0020]

[0022] According to one or more embodiments, this method employs an atomic layer deposition (ALD) process. In such embodiments, the substrate surface is exposed to a precursor (or reactive gas) sequentially or substantially sequentially. As used throughout this specification, “substantially sequential” means that, with some overlap, the majority of the precursor exposure period does not overlap with exposure to the co-reagent.

[0021]

[0023] As used herein and in the appended claims, terms such as “precursor,” “reactant,” and “reactive gas” are used interchangeably to refer to any gas species that can react with the substrate surface.

[0022]

[0024] As used herein, “atomic layer deposition” or “periodic deposition” refers to the sequential exposure of two or more reactive compounds to deposit a layer of material on a substrate surface. As used in this specification and the appended claims, terms such as “reactive compound,” “reactive gas,” “reactive species,” “precursor,” and “process gas” are used interchangeably to mean a substance having species that can react with the substrate surface or the material on the substrate surface in a surface reaction (e.g., chemisorption, oxidation, reduction) process. The substrate or a portion of the substrate is sequentially exposed to two or more reactive compounds introduced into the reaction zone of a processing chamber. In a time-domain ALD process, exposure to each reactive compound is separated by a time delay, allowing each compound to adhere to and / or react with the substrate surface. In a spatial ALD process, different portions of the substrate surface, or the material on the substrate surface, are simultaneously exposed to two or more reactive compounds, so that no single point on the substrate is substantially exposed to multiple reactive compounds simultaneously. As used in this specification and the attached claims, the term “substantially” as used in this respect means, as will be understood by those skilled in the art, that a small portion of the substrate may be exposed to multiple reactive gases simultaneously by diffusion, but is not intended to be exposed to them simultaneously.

[0023]

[0025] In one aspect of the time-domain ALD process, a first reactive gas (i.e., a first precursor or compound A) is pulsed into the reaction zone, followed by a first time delay. Next, a second precursor or compound B is pulsed into the reaction zone, followed by a second delay. During each delay time, a purge gas, such as argon, is introduced into the processing chamber to purge the reaction zone or to remove residual reactive compounds or by-products from the reaction zone. Alternatively, the purge gas may flow sequentially throughout the deposition process such that only the purge gas flows during the time delay between pulses of the reactive compounds. The reactive compounds are pulsed alternately until the desired film or film thickness is formed on the substrate surface. In either scenario, the ALD process that pulses compound A, the purge gas, compound B, and the purge gas is one cycle. The cycle starts with either compound A or compound B and continues through the respective sequence of the cycle until a film of the desired thickness is obtained. In some embodiments, there may be two reactants A and B that are pulsed and purged alternately. In other embodiments, there may be three or more reactants, A, B, and C, that are pulsed and purged alternately.

[0024]

[0026] In one aspect of the spatial ALD process, a first reactive gas and a second reactive gas (e.g., hydrogen radicals) are supplied to the reaction zone simultaneously but are separated by an inert gas curtain and / or a vacuum curtain. The substrate is moved relative to the gas supply device such that any given point on the substrate is exposed to the first reactive gas and the second reactive gas.

[0025]

[0027] Embodiments of the present disclosure provide a method for forming a high-quality transition metal dichalcogenide film in terms of crystallinity, particle size, continuity, and conductivity for use as a channel material, liner, or barrier layer in the miniaturization and scaling of integrated circuits. In one or more embodiments, the transition metal dichalcogenide film functions as a barrier layer for a logic device. For example, the transition metal dichalcogenide film functions as a barrier layer between a copper layer and a cobalt layer in a logic device and can prevent the electromigration of copper atoms and cobalt atoms. In one or more embodiments, the transition metal dichalcogenide film functions as a liner in 3D NAND applications. For example, the transition metal dichalcogenide film functioning as a liner can enable the nucleation of a metal to be subsequently deposited, adhesively bond the metal to the underlying dielectric material, and block the diffusion of elements into the underlying dielectric material. In one or more embodiments, the transition metal dichalcogenide film functions as a channel material in 3D NAND applications. In one or more embodiments, as an example, the transition metal dichalcogenide film has a carrier mobility better than polysilicon. The carrier mobility of the transition metal dichalcogenide film can improve the performance of 3D NAND devices.

[0026]

[0028] Embodiments of the present disclosure provide a low thermal history approach for realizing a high-quality 2D transition metal dichalcogenide film for temperature-sensitive device architectures.

[0027]

[0029] Referring to Figure 1, a structure 100 is shown, which includes a substrate 110 having at least one feature 120 thereon. These figures show a substrate with three features for illustrative purposes. However, those skilled in the art will understand that there may be more or fewer than three features. In one or more embodiments, the substrate 110 includes at least one feature 120. The shape of the feature 120 can be any suitable shape, including, but not limited to, trenches and cylindrical vias. The term “feature” as used in this context means an intentional surface irregularity. Suitable examples of features include, but are not limited to, trenches with a top, two sidewalls and a bottom, and peaks with a top and two sidewalls. Features can have any suitable aspect ratio (ratio of the depth of the feature to the width of the feature). In some embodiments, the aspect ratio is approximately 5:1, 10:1, 15:1, 20:1, 25:1, 30:1, 35:1 or 40:1 or greater. In one or more embodiments, at least one feature 120 is a trench. In one or more embodiments, at least one feature 120 is a dielectric material and a conductive material. In one or more embodiments, a transition metal oxide film (not shown) is selectively formed on the dielectric material.

[0028]

[0030] Referring to Figure 2, a structure 100 is shown, comprising a substrate 110 having at least one feature 120 thereon. In one or more embodiments, each of the at least one feature 120 has a transition metal dichalcogenide film 140 deposited thereon. In one or more embodiments, the structure 100 includes a metal filler 150 deposited on the substrate 110 and on each of the at least one feature 120 having the transition metal dichalcogenide film 140 thereon. In one or more embodiments, the metal filler 150 has a transition metal, including one or more of tungsten (W), molybdenum (Mo), tantalum (Ta), titanium (Ti), or ruthenium (Ru).

[0029]

[0031] Embodiments of the present disclosure relate to a method for depositing a film. In one or more embodiments, the method for depositing a film includes forming a transition metal oxide film on a substrate surface and converting the transition metal oxide film into a transition metal dichalcogenide film.

[0030]

[0032] In one or more embodiments, forming a transition metal oxide film includes forming a transition metal film and then oxidizing the transition metal film to form a transition metal oxide film. In one or more embodiments, oxidizing the transition metal film includes exposing the transition metal film to one or more heat treatments of O2 and O3. In one or more embodiments, the oxidized transition metal film (i.e., the transition metal oxide film) is sulfurized using thermal Ar / H2S or H2 / H2S gas. In one or more embodiments, the oxidized transition metal film (i.e., the transition metal oxide film) is sulfurized using plasma Ar / H2S or H2 / H2S gas. In certain embodiments, after forming a transition metal film containing tungsten (W), the transition metal film is oxidized to form a transition metal oxide film. In one or more embodiments, oxidizing a transition metal film having tungsten (W) includes exposing the transition metal film to one or more heat treatments of O2 and O3. In one or more embodiments, an oxidized transition metal film (i.e., a transition metal oxide film) is sulfurized using thermal Ar / H2S or H2 / H2S gas. In one or more embodiments, an oxidized transition metal film (i.e., a transition metal oxide film) is sulfurized using plasma Ar / H2S or H2 / H2S gas. In one or more embodiments, a transition metal oxide film having tungsten (W) is converted to WS2 by one or more sulfurization processes described herein.

[0031] In one or more embodiments, oxidizing a transition metal film involves exposing the transition metal film to one or more plasma treatments of O2 and O3. In one or more embodiments, plasma treatments using inert or reactive gases have been found to be effective. In one or more embodiments, the plasma treatment is generated by a remote plasma source (RPS), capacitively coupled plasma (CCP), or inductively coupled plasma (ICP) with an atmosphere such as argon (Ar), helium (He), ammonia (NH3), nitrogen (N2), hydrogen (H2), or a mixture thereof.

[0032]

[0034] In one or more embodiments, the conversion of a transition metal oxide film to a transition metal dichalcogenide film is performed using plasma power ranging from 25 watts (W) to 500 watts (W).

[0033]

[0035] In one or more embodiments, a transition metal oxide film having a thickness in the range of 15 Å to 25 Å is formed, and then the transition metal oxide film is converted to a transition metal dichalcogenide film.

[0035] In one or more embodiments, a transition metal oxide film having a thickness in the range of 16 Å to 24 Å, 17 Å to 23 Å, 18 Å to 22 Å, or 19 Å to 21 Å is formed, and then the transition metal oxide film is converted to a transition metal dichalcogenide film.

[0034]

[0036] In one or more embodiments, the method further includes repeatedly forming a transition metal oxide film and transforming the transition metal oxide film to form a transition metal dichalcogenide film having a final thickness of up to 200 Å. In one or more embodiments, the transition metal dichalcogenide film has a final thickness of up to 150 Å, up to 100 Å, or up to 50 Å.

[0035]

[0037] In one or more embodiments, the conversion of a transition metal oxide film to a transition metal dichalcogenide film is carried out at a temperature in the range of 350°C to 500°C and a pressure in the range of 1 Torr to 10 Torr.

[0036]

[0038] In one or more embodiments, the conversion of a transition metal oxide film to a transition metal dichalcogenide film is carried out for a period ranging from 30 to 60 minutes. In one or more embodiments, the conversion of a transition metal oxide film to a transition metal dichalcogenide film includes pulsing the transition metal oxide film with one or more of sulfur (S), selenium (Se), and tellurium (Te).

[0037]

[0039] Referring to Figure 3, one or more embodiments of the present disclosure relate to a method 200 for depositing a film. The method shown in Figure 3 represents an atomic layer deposition (ALD) process in which a substrate or substrate surface is sequentially exposed to a reactive gas in a manner that prevents or minimizes the gas-phase reaction of the reactive gas. In some embodiments, the method includes a chemical vapor deposition (CVD) process in which the reactive gas is mixed in a processing chamber to enable the gas-phase reaction of the reactive gas and the deposition of a thin film.

[0038]

[0040] In one or more embodiments of the present disclosure, the method 200 optionally includes pre-treating a substrate in operation 205 and forming a transition metal dichalcogenide film in a process cycle in deposition 210, sequentially exposing the substrate to a transition metal oxide precursor in operation 212, optionally purging the processing chamber in operation 214, exposing the substrate to a chalcogenide reactant in operation 216, and optionally purging the processing chamber in operation 218.

[0039]

[0041] In one or more embodiments of the present disclosure, Method 200 comprises converting a transition metal oxide film to a transition metal dichalcogenide film (not shown). In these embodiments, Method 200 comprises using two process cycles. In one or more embodiments, Method 200 optionally comprises pre-treating a substrate in operation 205, forming a transition metal oxide film in a transition metal process cycle in deposition 210, continuous exposure of the substrate to a transition metal precursor in operation 212, optionally purging the processing chamber in operation 214, exposing the substrate to oxide reactants in operation 216, and optionally purging the processing chamber in operation 218. In one or more embodiments, Method 200 further includes converting a transition metal oxide film to a transition metal dichalcogenide film (not shown) by forming a transition metal dichalcogenide film in a chalcogen process cycle in deposition 210, sequentially exposing the substrate to chalcogenide reactants in operation 216, and optionally purging the processing chamber in operation 218.

[0040]

[0042] Therefore, Figure 3 shows a method 200 for forming a transition metal dichalcogenide film using one or more process cycles as described herein.

[0041]

[0043] In some embodiments, method 200 optionally includes a pretreatment operation 205. The pretreatment may be any suitable pretreatment known to those skilled in the art. Suitable pretreatments include, but are not limited to, preheating, washing, immersion, removal of native oxides, or deposition of an adhesive layer (e.g., titanium nitride (TiN)). In one or more embodiments, an adhesive layer such as titanium nitride is deposited in operation 205. In other embodiments, no adhesive layer is deposited. In one or more embodiments, any pretreatment operation 205 includes flowing a plasma gas containing one or more of Ar / O2, Ar / H2, and Ar / H2S, followed by Ar / H2.

[0042]

[0044] In deposition 210, a process is performed to deposit a transition metal dichalcogenide film on a substrate (or substrate surface). The deposition process may include one or more operations for forming a film on the substrate. In one or more embodiments, deposition 210 includes forming a transition metal dichalcogenide film in a process cycle.

[0043]

[0045] In one or more embodiments, deposition 210 includes forming a transition metal oxide film in a transition metal oxide process cycle.

[0044]

[0046] In one or more embodiments, in operation 212, the substrate (or substrate surface) is exposed to a transition metal precursor to deposit a film on the substrate (or substrate surface). The transition metal precursor can be any suitable transition metal-containing compound that can react with (i.e., adsorb or chemisorb) the substrate surface to leave a transition metal-containing species on the substrate surface.

[0045]

[0047] In one or more embodiments, operation 212 involves exposing the substrate (or substrate surface) to a transition metal oxide precursor to deposit a film on the substrate (or substrate surface). The transition metal oxide precursor can be any suitable transition metal oxide-containing compound that can react with (i.e., adsorb or chemisorb) the substrate surface to leave transition metal oxide-containing species on the substrate surface. In one or more embodiments, the transition metal oxide precursor includes one or more of WOF4, WO2F2, WOCl4, WO2Cl2, WOBr4, WO2Br2, WOI4, WO2I2, MoOF4, MoO2F2, MoOCl4, MoO2Cl2, MoOBr4, MoO2Br2, MoOI4, MoO2I2, TaOF4, TaO2F2, TaOCl4, TaO2Cl2, TaOBr4, TaO2Br2, TaOI4, TaO2I2, TiOF4, TiO2F2, TiOCl4, TiO2Cl2, TiOBr4, TiO2Br2, TiOI4, TiO2I2, RuOF4, RuO2F2, RuOCl4, RuO2Cl2, RuOBr4, RuO2Br2, RuOI4, and RuO2I2.

[0046]

[0048] In operation 214, the processing chamber is optionally purged to remove unreacted transition metal oxide precursors, reaction products, and by-products. When used in this way, the term “processing chamber” includes portions of the processing chamber adjacent to the substrate surface, without encompassing the entire internal volume of the processing chamber. For example, the transition metal oxide precursors are purged from portions of the processing chamber adjacent to the substrate surface by any suitable technique, including, but not limited to, moving the substrate through a gas curtain to a portion or sector of the processing chamber that, in some embodiments, contains no or substantially no transition metal precursors, or transition metal oxide precursors, within a spatially separated sector of the processing chamber. In one or more embodiments, purging the processing chamber includes applying a vacuum. In some embodiments, purging the processing chamber includes flowing a purge gas over the substrate. In some embodiments, a portion of the processing chamber refers to a minute volume or small volume processing station within the processing chamber. The term “adjacent” with respect to the substrate surface means the physical space adjacent to the substrate surface that can provide sufficient space for surface reactions (e.g., adsorption of precursors) to occur. In one or more embodiments, the purge gas is selected from one or more of nitrogen (N2), helium (He), and argon (Ar). In one or more embodiments, a transition metal precursor, or in some embodiments a transition metal oxide precursor, is purged from the substrate surface before the substrate is exposed to the chalcogenide reactant.

[0047]

[0049] In one or more embodiments, in operation 214, the processing chamber is optionally purged to remove unreacted transition metal precursors, reaction products, and by-products.

[0048]

[0050] In operation 216, the substrate (or substrate surface) is exposed to a chalcogenide reactant to form a transition metal dichalcogenide film on the substrate. The chalcogenide reactant can react with transition metal-containing species on the substrate surface to form a transition metal dichalcogenide film. In some embodiments, the chalcogenide reactant includes a reducing agent. In one or more embodiments, the reducing agent may include any reducing agent known to those skilled in the art. In other embodiments, the chalcogenide reactant includes an oxidizing agent. In one or more embodiments, the oxidation may include any oxidizing agent known to those skilled in the art. In further embodiments, the chalcogenide reactant includes one or more oxidizing agents and reducing agents.

[0049]

[0051] In one or more embodiments, operation 216 exposes the substrate (or substrate surface) to an oxide reactant to form a transition metal oxide film in a transition metal oxide process cycle. After the transition metal oxide film is formed in the transition metal oxide process cycle, the transition metal oxide film is converted to a transition metal dichalcogenide film in another process cycle.

[0050]

[0052] In operation 218, the processing chamber is optionally purged after exposure to the chalcogenide reactant. The purging of the processing chamber in operation 218 may be the same process as the purging in operation 214, or it may be a different process. Purging the processing chamber, a portion of the processing chamber, or an area adjacent to the substrate surface removes unreacted chalcogenide reactant, oxide reactant, reaction products, and by-products from the area adjacent to the substrate surface. In one or more embodiments, in operation 218, the processing chamber is optionally purged after exposure to the oxide reactant.

[0051]

[0053] In decision 220, the thickness of the deposited film or the number of cycles of the precursor and reactant is considered. Once the deposited film reaches a predetermined thickness or a predetermined number of process cycles have been performed, method 200 proceeds to an optional post-treatment operation 230. If the deposited film thickness or the number of process cycles has not reached a predetermined threshold, method 200 returns to operation 210, and in operation 212, the substrate surface is exposed to the precursor again and the process continues.

[0052]

[0054] In one or more embodiments, the deposited film is substantially oxygen-free. As used herein, “substantially oxygen-free” means that the deposited film contains less than 5% oxygen on an atomic basis, including less than 4%, less than 3%, less than 2%, less than 1%, and less than 0.5%. Therefore, although not intended to be theoretical, it is assumed that the transition metal dichalcogenide film formed does not produce oxygen as a byproduct, and thus the possibility of etching / corroding the underlying metal layer is minimized.

[0053]

[0055] Optional post-processing operations 230 may be, for example, processes to modify film properties (e.g., annealing) or further film deposition processes to grow additional films (e.g., additional ALD or CVD processes). In some embodiments, optional post-processing operations 230 may be processes to modify the properties of the deposited film. In some embodiments, optional post-processing operations 230 include annealing the as-deposited film. In some embodiments, annealing is performed at temperatures in the range of about 300°C, 400°C, 500°C, 600°C, 700°C, 800°C, 900°C, or 1000°C. The annealing environment in some embodiments includes one or more inert gases (e.g., molecular nitrogen (N2), argon (Ar)) or reducing gases (e.g., molecular hydrogen (H2) or ammonia (NH3)), or oxidizing agents, for example, oxygen (O2), ozone (O3), or peroxides, not limited to these. Annealing can be performed for any suitable time. In some embodiments, the film is annealed for a predetermined time ranging from about 15 seconds to about 90 minutes, or from about 1 minute to about 60 minutes. In some embodiments, annealing the as-deposited film increases its density, decreases its resistivity, and / or increases its purity, and / or increases its crystallinity.

[0054]

[0056] Method 200 can be carried out at any suitable temperature, depending on, for example, the transition metal precursor, transition metal oxide precursor, chalcogenide reactant, oxide reactant, or the thermal history of the device. In one or more embodiments, the use of high-temperature processing may be undesirable for temperature-sensitive substrates such as logic devices. In some embodiments, exposure to the transition metal precursor or transition metal oxide precursor (operation 212) and exposure to the chalcogenide reactant or oxide reactant (operation 216) are carried out at the same temperature. In some embodiments, the substrate is maintained at a temperature in the range of 350°C to 500°C.

[0055]

[0057] In some embodiments, exposure to a transition metal precursor or transition metal oxide precursor (operation 212) is performed at a different temperature than exposure to a chalcogenide reactant or oxide reactant (operation 216). In some embodiments, the substrate is maintained at a first temperature in the range of 350°C to 500°C for exposure to a transition metal precursor or transition metal oxide precursor, and then exposed to a chalcogenide reactant or oxide reactant at a second temperature in the range of 350°C to 500°C. In some embodiments, both the metal precursor and the chalcogen / oxidant precursor are supplied at the same substrate temperature. A metal precursor adsorbed alone on the substrate may be self-limiting, and in some embodiments, multiple pulses of the metal precursor would not provide a multilayer film without chalcogen / oxidant. In some embodiments, both precursors form a complete cycle performed at the same substrate temperature.

[0056]

[0058] In the embodiment shown in Figure 3, the deposition operation 210 sequentially exposes the substrate (or substrate surface) to the transition metal oxide precursor and the chalcogen reactant. In another embodiment not shown, the substrate (or substrate surface) is simultaneously exposed to the transition metal oxide precursor and the chalcogen reactant in the CVD reaction. In the CVD reaction, the substrate (or substrate surface) is exposed to a gaseous mixture of the transition metal oxide precursor and the chalcogen reactant to deposit a transition metal dichalcogenide film of a predetermined thickness. In the CVD reaction, the transition metal dichalcogenide film can be deposited in a single exposure to the mixed reactive gas, or it can be deposited in multiple exposures to the mixed reactive gas with purging in between.

[0057]

[0059] In the embodiment shown in Figure 3, the deposition operation 210 sequentially exposes the substrate (or substrate surface) to the transition metal precursor and the oxidation reactant. In another embodiment not shown, the substrate (or substrate surface) is simultaneously exposed to the transition metal precursor and the oxidation reactant in the CVD reaction. In the CVD reaction, the substrate (or substrate surface) is exposed to a gaseous mixture of the transition metal precursor and the oxidation reactant to deposit a transition metal dichalcogenide film of a predetermined thickness. In the CVD reaction, the transition metal dichalcogenide film can be deposited in a single exposure to the mixed reactive gas, or it can be deposited in multiple exposures to the mixed reactive gas with purging in between.

[0058] In one or more embodiments, the deposition operation 210 is repeated to deposit WOF4, WO2F2, WOCl4, WO2Cl2, WOBr4, WO2Br2, WOI4, WO2I2, MoOF4, MoO2F2, MoOCl4, MoO2Cl2, MoOBr4, MoO2Br2, MoOI4, MoO2I2, TaOF4, TaO2F2, TaOCl4, TaO2Cl2, TaOBr4, T A film having a predetermined thickness can be formed containing one or more of the following: aO2Br2, TaOI4, TaO2I2, TiOF4, TiO2F2, TiOCl4, TiO2Cl2, TiOBr4, TiO2Br2, TiOI4, TiO2I2, RuOF4, RuO2F2, RuOCl4, RuO2Cl2, RuOBr4, RuO2Br2, RuOI4, and RuO2I2. In some embodiments, the deposition operation 210 is repeated many times to provide a film having a thickness in the range of 15 Å to 25 Å. In some embodiments, if the precursor is unstable above a certain temperature, deposition to the predetermined thickness is achieved by thermal decomposition without using another reactant.

[0059]

[0061] One or more embodiments of the present disclosure relate to a method for depositing a transition metal dichalcogenide film within a high aspect ratio feature. A high aspect ratio feature is a trench, via, or pillar with a height-to-width ratio of approximately 10, 20, or 50 or greater. In some embodiments, the transition metal-containing film is deposited conformally on the high aspect ratio feature. When used in this manner, the conformally deposited film has a thickness in the range of approximately 80–120% of the thickness of the bottom of the feature near the top of the feature.

[0060]

[0062] Some embodiments of this disclosure relate to methods for bottom-up gap filling of features. In a bottom-up gap filling process, the feature is filled from the bottom, whereas in a conformal process, the feature is filled from the bottom and sides. In some embodiments, the feature has a first material (e.g., a nitride) at the bottom and a second material (e.g., an oxide) at the sidewalls. A transition metal dichalcogenide film is selectively deposited on the first material relative to the second material to fill the feature in a bottom-up manner.

[0061]

[0063] According to one or more embodiments, the substrate is subjected to processing before and / or after layer formation. This processing can be performed in the same chamber or in one or more separate processing chambers. In some embodiments, the substrate is moved from a first chamber to another second chamber for further processing. The substrate can be moved directly from the first chamber to another processing chamber, or it can be moved from the first chamber to one or more transport chambers and then to another processing chamber. Thus, the processing apparatus can comprise multiple chambers communicating with transport stations. This type of apparatus is sometimes referred to as a "cluster tool" or "cluster system."

[0062]

[0064] Generally, a cluster tool is a modular system comprising multiple chambers that perform various functions, including substrate center detection and orientation, degassing, annealing, deposition, and / or etching. According to one or more embodiments, a cluster tool includes at least a first chamber and a central transport chamber. The central transport chamber can accommodate a robot that can reciprocate the substrate between the processing chamber and the load lock chamber. The transport chamber is typically maintained under vacuum and provides an intermediate stage for reciprocating the substrate from one chamber to another and / or to the load lock chamber located at the front end of the cluster tool. Two well-known cluster tools that can be adapted to this disclosure are Centura® and Endura®, both available from Applied Materials, Inc. in Santa Clara, California. However, the exact arrangement and combination of chambers can be modified for the purpose of performing specific steps of the processes described herein. Other processing chambers that can be used include, but are not limited to, periodic layer deposition (CLD), atomic layer deposition (ALD), chemical vapor deposition (CVD), physical vapor deposition (PVD), etching, pre-cleaning, chemical cleaning, thermal treatments such as RTP, plasma nitriding, degassing, orientation, hydroxide, and other substrate processing. Performing processing within the cluster tool chamber avoids contamination of the substrate surface by airborne impurities without oxidation before depositing the next film.

[0063]

[0065] According to one or more embodiments, the substrate is continuously under reduced pressure or “load-lock” conditions and is not exposed to ambient air when moving from one chamber to the next. Thus, the transport chamber is under reduced pressure and is “pumped down” under reduced pressure. An inert gas may be present in the processing chamber or transport chamber. In some embodiments, the inert gas is used as a purge gas to remove some or all of the reactants (e.g., reactants). According to one or more embodiments, a purge gas is injected at the outlet of the deposition chamber to prevent the reactants (e.g., reactants) from moving from the deposition chamber to the transport chamber and / or additional processing chambers. Thus, the flow of the inert gas forms a curtain at the chamber outlet.

[0064]

[0066] The substrates can be processed within a single-substrate deposition chamber, where a single substrate is loaded, processed, and unloaded before another substrate is processed. The substrates can also be processed in a continuous manner, similar to a conveyor system, where multiple substrates are individually loaded into a first section of the chamber, move within the chamber, and unloaded from a second section. The shape of the chamber and the associated conveyor system can form a straight or curved path. Furthermore, the processing chamber may be a carousel where multiple substrates move around a central axis and are subjected to processes such as deposition, etching, annealing, and cleaning along the entire carousel path.

[0065]

[0067] During processing, the substrate can be heated or cooled. Such heating or cooling can be achieved by any suitable means, including, but not limited to, changing the temperature of the substrate support and flowing a heated or cooled gas over the substrate surface. In some embodiments, the substrate support includes a heater / cooler that can be controlled to electrically change the substrate temperature. In one or more embodiments, the gas used (either a reactive or inert gas) is heated or cooled to locally change the substrate temperature. In some embodiments, the heater / cooler is positioned in a chamber adjacent to the substrate surface to convectivally change the substrate temperature.

[0066]

[0068] The substrate can be kept still or rotated during processing. The rotating substrate can be rotated sequentially or in individual steps (around the substrate axis). For example, the substrate may be rotated throughout the entire process, or it may be rotated only briefly between exposures to different reactive or purging gases. Rotating the substrate (sequentially or stepwise) during processing helps to minimize the effects of local variations in gas flow shape, for example, and to produce more uniform deposition or etching.

[0067]

[0069] Spatially relative terms such as "beneath," "below," "lower," "above," and "upper" may be used here to describe the relationship between one element or feature shown in the drawing and another, for the sake of clarity. It will be understood that spatially relative terms are intended to encompass different orientations of the device in use or operation, in addition to the orientation shown in the drawing. For example, if the device in the drawing is upside down, an element described as "below" or "directly below" another element or feature will therefore be oriented "above" the other element or feature. Thus, the exemplary term "below" may encompass both up and down orientations. The device may be oriented in other ways (rotated 90 degrees or in other directions), and the spatially relative descriptors used here may be interpreted accordingly.

[0068]

[0070] In the context describing the materials and methods discussed herein (particularly in the context of the following claims), the terms “a,” “an,” and “the,” and similar references, should be interpreted as covering both singular and plural forms, unless otherwise stated herein or unless clearly contradicted by the context. The enumeration of value ranges herein is merely intended to serve as a shorthand notation for referring individually to each individual value within the range, unless otherwise stated herein, and each individual value is incorporated into the specification as if it were individually stated herein. All methods described herein may be performed in any appropriate order, unless otherwise stated herein or unless clearly contradicted by the context. The use of any examples or illustrative language provided herein (e.g., “etc.”) is merely intended to better illustrate the materials and methods and does not impose any limitation on their scope unless otherwise specified in the claims. Nothing in this specification should be interpreted as indicating an element that is not claimed as essential to the implementation of the disclosed materials and methods.

[0069]

[0071] Throughout this specification, any reference to “one embodiment,” “a particular embodiment,” “one or more embodiments,” or “embodiment” means that any particular feature, structure, material, or property described in relation to an embodiment is included in at least one embodiment of this disclosure. Therefore, any occurrence of phrases such as “in one or more embodiments,” “a particular embodiment,” “in one embodiment,” or “in an embodiment” in various places throughout this specification does not necessarily refer to the same embodiment of this disclosure. Furthermore, any particular feature, structure, material, or property may be combined in any suitable manner in one or more embodiments.

[0070]

[0072] While the disclosures herein have been described with reference to specific embodiments, those skilled in the art will understand that the embodiments described are merely illustrative of the principles and applications of the disclosure. It will be apparent to those skilled in the art that various modifications and variations can be made to the methods and apparatus of the disclosure without departing from the spirit and scope of the disclosure. Accordingly, the disclosure may include modifications and variations that fall within the scope of the appended claims and their equivalents.

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