Method for forming rhenium-containing films on substrates by cyclic deposition process and related semiconductor device structures - Patents.com

Abstract

To provide a method for forming a rhenium-containing film on a substrate by periodical deposition.SOLUTION: A method includes steps of; bringing a substrate into contact with a first vapor-phase reaction material containing a rhenium precursor selected from a group comprising a rhenium oxyhalide precursor, an alkyl rhenium oxide precursor, a cyclopentadienyl-based rhenium precursor and a rhenium carbonyl halide precursor; and bringing the substrate into contact with a second vapor-phase reaction material containing at least one of an oxygen-containing precursor, a boron-containing precursor, a sulfur-containing precursor and a hydrogen-containing precursor.SELECTED DRAWING: None

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE This disclosure relates generally to methods of forming rhenium-containing films on substrates by a cyclic deposition process, and in particular to methods of forming rhenium-containing films by a cyclic deposition process utilizing a rhenium precursor. [Background technology]

[0002] Rhenium-containing films can be utilized in a wide range of technological applications. For example, elemental rhenium films can be used as catalysts in high-temperature superalloys, superconducting applications, adhesion layers, liners, diffusion barriers, seed layers, seed layers for improving the growth of other materials, and microelectronic applications. In addition, rhenium oxide can exhibit low electrical resistivity and thus can be utilized as electrodes in semiconductor device structures, such as dynamic random access memory (DRAM) devices. Moreover, rhenium sulfides, such as rhenium disulfide (ReS2), have been shown to exhibit behavior similar to 2D materials even in 3D bulk form. Thus, rhenium sulfide can find applications in tribology, other low-friction applications, solar cell applications, and quantum computing and ultra-high-speed data processing. Thus, methods of forming rhenium-containing films and related semiconductor device structures that include rhenium-containing films are highly desirable. Summary of the Invention

[0003] This Summary is provided to introduce a selection of concepts in a simplified form that are described in further detail below in the Detailed Description of Exemplary Embodiments of this Disclosure. This Summary 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.

[0004] In some embodiments, a method is provided for forming a rhenium-containing film on a substrate by a cyclic deposition process, the method can include contacting the substrate with a first gas-phase reactant comprising a rhenium precursor selected from the group consisting of a rhenium oxyhalide precursor, an alkyl rhenium oxide precursor, a cyclopentadienyl-based rhenium precursor, or a rhenium carbonyl halide precursor, and contacting the substrate with a second gas-phase reactant.

[0005] For purposes of summarizing the invention and the advantages achieved over the prior art, certain objects and advantages of the invention are described herein above. Of course, it should be understood that not necessarily all such objects or advantages may be achieved by any particular embodiment of the invention. Thus, those skilled in the art will recognize that the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages, for example, as taught or suggested herein, without necessarily achieving other objects or advantages that may be taught or suggested herein.

[0006] All of these embodiments are intended to be within the scope of the invention disclosed herein. These and other embodiments will be readily apparent to those skilled in the art from the following detailed description of several embodiments, taken in conjunction with the accompanying drawings, and the invention is not limited to any particular embodiment disclosed. [Brief description of the drawings]

[0007] While the specification concludes with claims particularly pointing out and distinctly claiming what are regarded as embodiments of the present disclosure, the advantages of the presently disclosed embodiments may be more readily ascertained from the following description of certain specific examples of the presently disclosed embodiments when read in conjunction with the accompanying drawings.

[0008] [Figure 1] FIG. 1 shows a non-limiting exemplary process flow illustrating a method for forming a rhenium oxide film on a substrate by a cyclic deposition process according to an embodiment of the present disclosure.

[0009] [Diagram 2] FIG. 2 shows a non-limiting exemplary process flow illustrating an additional method for forming a rhenium oxide film on a substrate by a cyclic deposition process according to embodiments of the present disclosure.

[0010] [Diagram 3] FIG. 3 shows a non-limiting exemplary process flow illustrating a further method for forming a rhenium oxide film on a substrate by a cyclic deposition process according to an embodiment of the present disclosure.

[0011] [Figure 4] 4A-4C show cross-sectional schematic diagrams of semiconductor structures that may be formed by a process for forming a low resistivity rhenium oxide film on a substrate by a cyclic deposition process according to embodiments of the present disclosure.

[0012] [Diagram 5] FIG. 5 shows a non-limiting exemplary process flow illustrating a method for forming a rhenium sulfide film on a substrate by a cyclic deposition process according to an embodiment of the present disclosure.

[0013] [Figure 6] FIG. 6 shows a non-limiting exemplary process flow illustrating an additional method for forming a rhenium sulfide film on a substrate by a cyclic deposition process according to embodiments of the present disclosure.

[0014] [Figure 7] FIG. 7 shows a non-limiting exemplary process flow illustrating a method for forming an elemental rhenium film on a substrate by a cyclic deposition process according to an embodiment of the present disclosure.

[0015] [Figure 8] FIG. 8 shows a non-limiting exemplary process flow illustrating an additional method for forming an elemental rhenium film on a substrate by a cyclic deposition process according to embodiments of the present disclosure.

[0016] [Figure 9] FIG. 9 illustrates a cross-sectional schematic diagram of a semiconductor device structure including a rhenium-containing film formed according to an embodiment of the present disclosure.

[0017] [Figure 10] FIG. 10 illustrates an exemplary reaction system configured to perform a cyclic deposition method according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Although several embodiments and examples are disclosed below, it will be understood by those skilled in the art that the present invention extends beyond the specifically disclosed embodiments and / or applications of the present invention, as well as obvious modifications and equivalents thereof, and therefore it is not intended that the scope of the disclosed invention should be limited by the specific disclosed embodiments described below.

[0019] The figures shown herein are not meant to be actual illustrations of any particular materials, structures or devices, but merely idealized representations used to explain embodiments of the present disclosure.

[0020] As used herein, the term "rhenium oxyhalide precursor" refers to a compound of the general formula Re a O b X c where Re is rhenium, O is oxygen, X is a halogen atom such as, for example, fluorine (F), chlorine (Cl), bromine (Br), or iodine (I), and a, b, and c are integers greater than or equal to 1.

[0021] As used herein, the term "cyclic chemical vapor deposition" can 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 a desired deposit.

[0022] As used herein, the term "substrate" can refer to any underlying material or materials that can be used or upon which a device, circuit, or film can be formed.

[0023] The term "atomic layer deposition" (ALD) as used herein refers to a vapor deposition process, in which deposition cycles, including multiple successive deposition cycles, are performed in a reaction chamber. Typically, during each cycle, a precursor chemisorbs to a deposition surface (e.g., the surface of a substrate or a surface of a previously deposited underlayer, such as a material deposited using a previous ALD cycle) and forms a monolayer or submonolayer that does not readily react with additional precursors (i.e., a self-limiting reaction). If necessary, a reactant (e.g., another precursor or a reactant gas) can then be introduced into the process chamber for use in converting the chemisorbed precursor to a desired material on the deposition surface. Typically, this reactant can further react with the precursor. Additionally, a purge step can be utilized during each cycle to remove excess precursor from the process chamber after conversion of the chemisorbed precursor, and / or to remove excess reactants and / or reaction by-products from the process chamber. Additionally, the term "atomic layer deposition" as used herein is also meant to include processes denoted by related terms, such as, for example, "chemical vapor deposition atomic layer deposition," "atomic layer epitaxy" (ALE), molecular beam epitaxy (MBE), gas source MBE, or metalorganic MBE, as well as chemical beam epitaxy when performed with alternating pulses of precursor compositions, reactive gases, and purge (e.g., inert carrier) gases.

[0024] As used herein, the terms "film" and "thin film" are intended to mean any continuous or non-continuous structures and materials formed by the methods disclosed herein. "Films" and "thin films" can include, for example, 2D materials, nanorods, nanolaminates, nanotubes, or nanoparticles, or partial or complete molecular layers, or partial or complete atomic layers, or clusters of atoms and / or molecules. "Films" and "thin films" can include materials or layers that have pinholes, yet are at least partially continuous.

[0025] It should be noted that many example materials are provided throughout the embodiments of this disclosure, and the chemical formulas provided for each of the example materials should not be construed as limiting, nor should the non-limiting example materials provided be limited by certain example stoichiometries.

[0026] The present disclosure includes methods and associated semiconductor device structures that may form and utilize rhenium-containing films, such as elemental rhenium films, rhenium oxide films, rhenium sulfide films, and rhenium boride films, that may be utilized in a wide variety of technology applications.

[0027] As a non-limiting example, certain rhenium oxide films, such as rhenium trioxide (ReO3), can exhibit very low electrical resistivity and therefore can be utilized in numerous semiconductor device applications, including, but not limited to, as device interconnects, barrier layers, Schottky devices, metal-insulator-semiconductor (MIS) devices, metal-insulator-metal devices (MIM), and as part of gate electrodes.

[0028] Rhenium oxide can also be used to dope semiconductor devices. For example, rhenium oxide can be used to adjust the electrical conductivity of semiconductor materials and to adjust the adhesion of certain materials. In a further example, rhenium oxide can be used to form interesting mixed compounds, such as in solid-solid reactions.

[0029] The attractive physical properties of rhenium oxides, such as rhenium dioxide, rhenium trioxide, or rhenium heptoxide, may enable several novel applications. In some embodiments, rhenium oxides may be utilized for bottom-up filling or filling of trench, pit, or gap structures in complex 3D structures. Bottom-up and / or gap filling with rhenium oxide may be achieved in many ways, including, but not limited to, depositing rhenium oxide at a low deposition temperature and then annealing the deposited rhenium oxide film at a higher temperature to lift the rhenium oxide film into the lower region of the 3D structure. The annealing temperature of the rhenium oxide film may be greater than 50° C., greater than 100° C., or greater than 200° C., or greater than 300° C., or greater than 350° C. The annealing of the rhenium oxide film may be performed in an oxidizing or reducing environment to maintain a specific composition of the rhenium oxide film. For example, annealing of the rhenium oxide film may be performed in an environment containing at least one of nitric oxide (NO), nitrogen dioxide (NO2), sulfur oxides (eg, SO2 or SO3), oxygen, or water.

[0030] As a further non-limiting example, rhenium oxide, such as Re2O7, may be utilized as a raw material in a chemical vapor deposition (CVD) process, where Re2O7 may begin to sublime at temperatures above about 100° C., or above about 150° C., or above about 180° C. to deposit Re2O7 for thin film and / or gap-filling applications.

[0031] In some embodiments of the present disclosure, the deposition temperature may be carefully controlled such that a first composition of rhenium oxide film may be deposited on a second composition of rhenium oxide film, the first composition and the second composition being different from each other. For example, at a deposition temperature of about 220° C. to 350° C., a rhenium oxide film may be deposited that does not include the composition Re2O7.

[0032] In some embodiments, the rhenium oxide film may be deposited on a template structure, such as a corrugated surface and / or a patterned surface, for example, for the formation of quantum dots, nanodots, nanowires, or nanopatterns comprising rhenium oxide material. In such embodiments, the initial or final material may be any one of rhenium oxide, elemental rhenium metal, rhenium boride, or rhenium sulfide. Depending on the desired rhenium-containing material, various processing steps may be utilized, such as oxidation, reduction, or sulfurization of the initial rhenium-containing film. As mentioned above, an annealing step may also be utilized to allow the rhenium-containing material to accumulate at the lower apexes of the corrugations or the lower regions of the 3D structure.

[0033] In some embodiments, the deposited rhenium-containing film or alloys thereof may contain any of boron, sulfur, carbon, nitrogen, phosphorus, or combinations thereof. In some embodiments, the rhenium-containing film may be classified as one of the possible phases of rhenium carbide, rhenium boride, rhenium nitride, rhenium phosphide, or in some cases may contain more than one element. For example, the rhenium-containing film may contain any possible combination of boron and carbon, nitrogen and boron, or boron, carbon, nitrogen, and phosphorus. In some embodiments of the present disclosure, the rhenium-containing film may include rhenium boron carbide (ReBC), rhenium diboride (ReB2), rhenium triboride (Re2B3), or rhenium boride (ReB, Re3B7, Re3B, and Re2B).

[0034] In some embodiments of the present disclosure, the rhenium-containing film may include boron, carbon, nitrogen, sulfur, phosphorus, or any possible combination thereof. Non-limiting applications of such mixed alloys of rhenium, boron, carbon, nitrogen, or phosphorus may be utilized as adhesion improving layers, seed layers, diffusion barriers, hard coatings, high modulus super hard layers, or liners.

[0035] In some embodiments, the rhenium-containing film can include at least one of ReBC, ReB, ReC, Re3P4, Re2P, ReP4, Re3N, Re2N, ReN, ReN2, ReN4, Re2C, ReC, Re4C, ReB2. In some embodiments, the rhenium-containing film can be used as a superconducting layer, a hard mask in patterning applications, an etch stop layer in patterning applications, a coating for reaction chambers and components of reaction chambers and etch reactors, a protective coating against etch chemistries, and ReP4 as a semiconducting layer.

[0036] In some cases, it may be desirable to form voids, and low boiling point rhenium oxide films may be utilized in such applications. For example, annealing the rhenium oxide film at temperatures above about 400° C. may completely sublimate the rhenium oxide film from the filled gap features, or sublimate the deposited rhenium oxide film. In some embodiments, sublimation of the rhenium oxide film may leave voids, or alternatively the rhenium oxide film may be utilized as a sacrificial layer and / or a patterning layer for patterning applications.

[0037] In some embodiments, the rhenium-containing films may be utilized in back-end (BEOL) applications such as metal contacts, which may be deposited on an underlying liner layer, adhesion layer, seed layer, or diffusion barrier layer, and in some applications, the metal contacts may be capped by a metal alloy. For example, in some applications, the metal interconnect may be elemental rhenium, which may be deposited on an underlying rhenium alloy, such as rhenium carbide, rhenium boride, rhenium nitride, or rhenium phosphide. In some embodiments, the metal precursor utilized to deposit the metal contact may be similar to that utilized in the deposition of the liner layer, adhesion layer, seed layer, or diffusion barrier layer, with only the selection of the second reactant and / or process conditions (e.g., deposition temperature). This approach may be advantageous in processing since only one metal precursor is used, and this approach may be applied to other processes utilizing different metals, such as, for example, cobalt as the metal contact or interconnect, and cobalt phosphide as the adhesion layer or liner layer. A similar approach may be utilized for ruthenium-based processes and their associated carbides.

[0038] In addition, rhenium oxide films, such as, for example, rhenium(VII) oxide (Re2O7), may exhibit dielectric properties and thus may be utilized in DRAM devices and as capacitor structures. ReO2 may find applications in, for example, spintronic devices, as well as memory devices such as resistive RAM. In some embodiments, rhenium oxide may be utilized in catalytic science. In some embodiments, the deposited rhenium-containing films may facilitate selective deposition or etching. For example, ReO x The catalytic effect of may assist some ALD precursors to react or decompose on its surface.

[0039] Additionally, rhenium oxide films, such as, for example, rhenium trioxide (ReO3), exhibit a low melting point, which can be benefited from by capping the rhenium oxide film with a capping layer, such as, for example, titanium nitride (TiN), and then thermally annealing the rhenium oxide film to form a single crystal rhenium oxide film or to increase the grain size of the crystals that comprise the rhenium oxide film, thereby decreasing the electrical resistivity of the rhenium oxide film.

[0040] Accordingly, embodiments of the present disclosure may include a method of forming a rhenium-containing film on a substrate by a cyclic deposition process. In some embodiments, the method may include contacting a substrate with a first gas-phase reactant comprising a rhenium precursor selected from the group consisting of a rhenium oxyhalide precursor, an alkyl rhenium oxide precursor, a cyclopentadienyl-based rhenium precursor, or a rhenium carbonyl halide precursor, and contacting the substrate with a second gas-phase reactant.

[0041] Methods for forming rhenium-containing films disclosed herein can include, for example, atomic layer deposition (ALD) or cyclic deposition processes such as cyclic chemical vapor deposition (CCVD).

[0042] A non-limiting exemplary embodiment of a cyclic deposition process includes atomic layer deposition (ALD), which is based on a typical self-limiting reaction whereby sequential and alternating pulses of reactants are used to deposit approximately one atomic (or molecular) monolayer of material per 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 unreactive with the gas-phase reactant of the same reactant. The substrate is then contacted with a different reactant that reacts with the previous termination, allowing for successive depositions. Thus, each cycle of alternating pulses typically leaves approximately one monolayer or less of the desired material. However, as noted above, one skilled in the art will recognize that more than one monolayer of material can be deposited in one or more ALD cycles, for example, if several gas-phase reactions occur despite the alternating nature of the process.

[0043] For example, in an ALD-type process utilized for the formation of rhenium-containing films, such as elemental rhenium, rhenium oxide, rhenium sulfide, or rhenium boride films, one deposition cycle can include exposing a substrate to a first gas-phase reactant, removing any unreacted first reactant and reaction by-products from the reaction chamber, and exposing the substrate to a second gas-phase reactant, followed by a second removal step. In some embodiments of the present disclosure, the first gas-phase reactant can include a rhenium precursor and the second gas-phase reactant can include at least one of an oxygen-containing precursor, a sulfur-containing precursor, a boron-containing precursor, or a hydrogen-containing precursor.

[0044] In some embodiments of the present disclosure, the boron-containing precursor is represented by the general formula B n H n+x where n and x are integers equal to or greater than 1. In some embodiments, the boron-containing precursor comprises a borane of the general formula R 1 R 2 R 3 The boron-containing precursor may include an alkyl borate salt of OB, where R is any alkyl or aryl group. In some embodiments, the boron-containing precursor may include boron hydride (BH), diborane (BH), decaborane (B 10 H 14 ), Tetraborane (B4H 10 ), trimethyl borate or triethyl borate.

[0045] The precursors can be separated by an inert gas, such as argon (Ar) or nitrogen (N2), to prevent gas-phase reactions between the reactants and allow self-saturating surface reactions. However, in some embodiments, the substrate can be moved to contact the first and second gas-phase reactants separately. Since the reaction is self-saturating, strict temperature control of the substrate and precise dosage control of the precursors may not be necessary. However, the substrate temperature is such that the incident gas species do not condense into a monolayer and do not decompose at the surface. Before contacting the substrate with the next reactive chemical, excess chemicals and reaction by-products, if any, are removed from the substrate surface, for example by purging the reaction space or by moving the substrate. Undesired gas molecules can be effectively evacuated from the reaction space using an inert purge gas. A vacuum pump can be used to facilitate purging.

[0046] The reactor that can be used to deposit the rhenium-containing film can be used for the cyclic deposition process described herein. Such reactors include ALD reactors configured to supply precursors as well as CVD reactors. According to some embodiments, a showerhead reactor can be used. According to some embodiments, a cross-flow, batch, mini-batch, or spatial ALD reactor can be used.

[0047] In some embodiments of the present disclosure, a batch reactor may be used. In some embodiments, a vertical batch reactor may be used. In other embodiments, the batch reactor comprises a mini-batch reactor configured to accommodate 10 or less wafers, 8 or less wafers, 6 or less wafers, 4 or less wafers, or 2 or less wafers. In some embodiments where a batch reactor is used, the wafer-to-wafer non-uniformity is less than 5% (1 sigma), or less than 3%, or less than 2%, or less than 1%, or even less than 0.5%.

[0048] The exemplary cyclical deposition process described herein may optionally be performed in a reactor or reaction chamber coupled to a cluster tool. In a cluster tool, the temperature of the reaction chambers in each module may be kept constant since each reaction chamber is dedicated to one type of process, improving throughput compared to a reactor that heats the substrate to a process temperature before each run. Additionally, a cluster tool may reduce the time to evacuate the reaction chamber to the desired process pressure level between substrates. In some embodiments of the present disclosure, the exemplary cyclical deposition process for the formation of rhenium-containing films disclosed herein may be performed in a cluster tool including multiple reaction chambers, each individual reaction chamber may be utilized to expose the substrate to an individual precursor gas, and the substrate may be transported between different reaction chambers for exposure to the multiple precursor gases, with the substrate transport being performed under a controlled environment to prevent oxidation / contamination of the substrate. In some embodiments of the present disclosure, the cyclical deposition process for the formation of rhenium-containing films may be performed in a cluster tool with multiple reaction chambers, each individual reaction chamber may be configured to heat the substrate to a different temperature.

[0049] A stand-alone reactor may be equipped with a load lock, in which case there is no need to cool the reaction chamber between each run.

[0050] In some embodiments, the deposition process utilized in forming the rhenium-containing film may include multiple deposition cycles, such as, for example, ALD cycles or cyclic CVD cycles.

[0051] In some embodiments, the cyclic deposition process can be a hybrid ALD / CVD or cyclic CVD process. For example, in some embodiments, the growth rate of an ALD process may be low compared to a CVD process. One approach to increase the growth rate is to operate at a higher substrate temperature than typically used in an ALD process, resulting in part of a chemical vapor deposition process, but also utilizing sequential introduction of precursors, such a process may be referred to as cyclic CVD. In some embodiments, the cyclic CVD process may include the introduction of two or more precursors into the reaction chamber, with periods of overlap between the two or more precursors in the reaction chamber resulting in both the ALD component of the deposition and the CVD component of the deposition. For example, the cyclic CVD process may include a continuous flow of a first precursor and periodic pulse injection of a second precursor into the reaction chamber.

[0052] According to some embodiments of the present disclosure, an ALD process is used to deposit a rhenium-containing film on a substrate, such as an integrated circuit workpiece. In some embodiments of the present disclosure, each ALD cycle may include two or more separate deposition steps or stages. In a first stage of a deposition cycle (the "rhenium stage"), the surface of the substrate on which deposition is desired may be contacted with a first gas-phase reactant that includes a rhenium precursor that chemisorbs onto the surface of the substrate and forms about one or less monolayers of reactant species on the surface of the substrate. In a second stage of deposition, the substrate surface on which deposition is desired may be contacted with a second gas-phase reactant that includes at least one of an oxygen-containing precursor, a sulfur-containing precursor, a boron-containing precursor, or a hydrogen-containing precursor. Additional stages may include an oxidation stage, a reduction stage, and / or a preclean stage.

[0053] In some embodiments of the present disclosure, a particular oxide of rhenium may be selectively deposited on the surface of another composition of rhenium oxide. Such selective oxidation can be controlled by specifically selecting the oxidizing environment. In some embodiments, a particular oxidizing environment may be periodically applied to the cyclic deposition process.

[0054] In some embodiments of the present disclosure, a reduction step may be applied to the cyclic deposition process. In such embodiments, a reduction step may be required to maintain a particular oxidation state of rhenium in the rhenium-containing film, which may contain, but is not limited to, rhenium, oxygen, carbon, hydrogen, nitrogen, halides, phosphorus, sulfur, or boron.

[0055] Exemplary Cyclic Deposition Process for Forming Rhenium Oxide Films In some embodiments of the present disclosure, the cyclic deposition process involves the deposition of rhenium oxide, such as rhenium(IV) oxide (ReO), rhenium trioxide (ReO), rhenium(VII) oxide (ReO), or a compound of the general formula Re a O b where a and b have a value less than 7. In some embodiments, the rhenium oxide film may be utilized to form rhenium oxide having the general formula ReO x where x is less than 2.

[0056] In some embodiments, the cyclic deposition process may include forming a rhenium oxide film by a surface reaction between a first gas phase reactant and a second gas phase reactant. In some embodiments, the cyclic deposition process may include forming an intermediate rhenium oxide film followed by contacting the intermediate rhenium oxide film with a reducing agent precursor to form a rhenium oxide film of a desired composition. In some embodiments, the cyclic deposition process may include forming an intermediate rhenium oxide film followed by contacting the intermediate rhenium oxide film with an additional oxygen-containing precursor to form a rhenium oxide film of a desired composition.

[0057] An exemplary rhenium oxide film formation process may be understood with reference to FIG. 1, which illustrates an exemplary cyclic deposition process 100 for the formation of a rhenium oxide film.

[0058] 1 illustrates an exemplary rhenium oxide formation process 100 that includes a cyclical deposition phase 105. The exemplary rhenium oxide formation process 100 may begin with process block 110, which includes providing a substrate into a reaction chamber and heating the substrate to a desired deposition temperature.

[0059] In some embodiments of the present disclosure, the substrate may include a planar substrate or a patterned substrate including 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 comprise an engineered substrate, where a surface semiconductor layer is disposed on a bulk support with an intervening buried oxide (BOX) disposed therebetween. In some embodiments, a liner may be used, which may include, for example, a metal, a metal nitride, a metal boride, a metal carbide, a metal phosphide, or a metal sulfide. In some embodiments, the liner may include at least one of titanium nitride, tantalum nitride, tantalum carbide, tungsten carbide, molybdenum, niobium boride, or niobium carbide.

[0060] The patterned substrate may comprise a substrate that may include semiconductor device structures formed in or on a 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 one or more secondary surfaces that may include a single crystal surface and / or a non-single crystal surface, such as a polycrystalline surface and / or an amorphous surface. The single crystal surface may include, for example, one or more of silicon (Si), silicon germanium (SiGe), germanium tin (gESn), or germanium (Ge). The polycrystalline or amorphous surface may include a dielectric material, such as an oxide, oxynitride, or nitride, such as silicon oxide and silicon nitride.

[0061] The reaction chamber utilized for deposition may be an atomic layer deposition reaction chamber, or a chemical vapor deposition reaction chamber, or any of the reaction chambers as previously described herein. In some embodiments of the present disclosure, the substrate may be heated to a desired deposition temperature for the subsequent cyclical deposition phase 105. For example, the substrate may be heated to a substrate temperature of less than about 750° C., or less than about 650° C., or less than about 550° C., or less than about 450° C., or less than about 350° C., or less than about 250° C., or less than about 150° C. In some embodiments of the present disclosure, the substrate temperature during the cyclical deposition phase may be between 300° C. and 750° C., or between 400° C. and 600° C., or between 400° C. and 450° C. In some embodiments, the substrate temperature during the cyclical deposition phase may be between 80° C. and 150° C., or between 150° C. and 200° C., or even between 200° C. and 350° C.

[0062] Upon heating the substrate to a desired deposition temperature, the exemplary rhenium oxide deposition process 100 can continue with a cyclical deposition phase 105 by process block 120, which includes contacting the substrate with a first gas-phase reactant, particularly a first gas-phase reactant that in some embodiments includes a rhenium gas-phase reactant, i.e., a rhenium precursor.

[0063] In some embodiments of the present disclosure, the rhenium precursor may include a rhenium halide precursor. In some embodiments, the rhenium halide precursor may have an oxidation state of either 4, or 5, or 6, or 7. In some embodiments, the rhenium halide precursor may include at least one of rhenium chloride, rhenium fluoride, rhenium bromide, or rhenium iodide. In some embodiments, the first gas phase reactant may include rhenium chloride, such as, for example, rhenium hexachloride (ReCl6) or rhenium pentachloride (ReCl5). In some embodiments, the first gas phase reactant may include rhenium bromide, such as, for example, rhenium pentabromide (ReBr5). In some embodiments, the first gas phase reactant may include rhenium fluoride, such as, for example, rhenium pentafluoride (ReF5), rhenium heptafluoride (ReF7), rhenium hexafluoride (ReF6).

[0064] In some embodiments of the present disclosure, the rhenium precursor may include a rhenium oxyhalide precursor, the term "rhenium oxyhalide precursor" having the general formula Re a O b X c where Re is rhenium, O is oxygen, X is a halogen atom such as, for example, fluorine (F), chlorine (Cl), bromine (Br), or iodine (I), and a, b, and c are integers greater than or equal to 1.

[0065] In some embodiments, the rhenium oxyhalides may include various oxidation states. For example, the oxidation state of rhenium in the rhenium oxyhalides may be 2, or 3, or 4, or 5, or 6, or even 7. In some embodiments, the rhenium oxyhalides may include one, two, or three neutral ligands. For example, the neutral ligands may be alkyl or aryl amines, alkyl or aryl phosphines, or cyclic amines, such as pyridine. In some embodiments, the rhenium oxyhalides may include oxotrichlorobis(triphenylphosphine)rhenium(V)ReOCl3[PPh3]2, oxotrichlorobis(trimethylphosphine)rhenium(V)ReOCl3[(CH3)3P]2, or oxotrichlorobis(dimethylamino)rhenium(V)ReOCl3[(Me2NH)]2. In some embodiments, the rhenium precursor may include a rhenium oxyfluoride, including but not limited to rhenium oxyfluoride (ReOF), rhenium trioxyfluoride (ReO3F), rhenium oxytetrafluoride (ReOF4), rhenium oxypentafluoride (ReOF5), or rhenium dioxyfluoride (ReO2F2). In some embodiments, the rhenium precursor may include a rhenium oxychloride, including but not limited to rhenium oxychloride (ReOCl), rhenium trioxychloride (ReO3Cl), or rhenium dioxydichloride (ReO2Cl3).

[0066] In some embodiments, the rhenium precursor can include an alkylrhenium oxide, such as an alkylrhenium trioxide (RReO3, where R is an alkyl group). In some embodiments, the alkylrhenium oxide precursor can include methylrhenium trioxide (CH3ReO3).

[0067] In some embodiments, the rhenium precursor may include a cyclopentadienyl-based rhenium precursor. In some embodiments, the cyclopentadienyl-based rhenium precursor may be a cyclopentadienyl rhenium hydride, a pentacarbonyl hydrido rhenium ReH[CO]5, a cyclopentadienyl rhenium carbonyl, or a dirhenium decarbonyl Re2[CO] 10 In some embodiments, the cyclopentadienyl rhenium hydride precursor can include ReHCp2. In some embodiments, the cyclopentadienyl rhenium carbonyl can have an oxidation state of either 1, or 2, or 3, or 4, or 5, or 6. For example, the cyclopentadienyl rhenium carbonyl can include ReCp[CO]3, aminocyclopentadienyl rhenium carbonyl Re(C5H4NH2)(CO)3, or Re[C5Me5][CO]3.

[0068] In some embodiments, the rhenium precursor has an oxidation state of 1, or 2, or 3, or 4, or 5, or 6 and has the general formula ReX a [CO] b where X can be fluorine, bromine, chlorine, or iodine, and "a" and "b" can be greater than or equal to 1. In some embodiments, the rhenium carbonyl halide precursor can include chloropentacarbonylrhenium(I) ReCl[CO]5, or bromopentacarbonylrhenium(I) ReBr[CO]5.

[0069] In some embodiments of the present disclosure, metal precursors can be selected to deposit metals and metal alloys by selecting the second reactant and / or by modifying the process conditions. In some embodiments, the second reactant can be a hydrogen or nitrogen-containing precursor, such as, for example, hydrogen gas, ammonia, alkylamines, ammonia-hydrogen mixtures, nitrogen-hydrogen plasma, hydrogen plasma, or a boron-containing precursor, such as, for example, boranes, alkyl borates, or a carbon-containing precursor, such as alkyl halides, organic mixed halide compounds, saturated or unsaturated and aliphatic or non-aliphatic alkanes, or a phosphorus-containing precursor, such as, for example, phosphine (PH3) or alkyl phosphines.

[0070] In some embodiments, the organic mixed halide has the general formula C a X b Y d where C is carbon, X is a halide such as chlorine or bromine or iodine or fluorine, and a, b, and d are integers greater than 1.

[0071] In some embodiments of the present disclosure, contacting the substrate with a first gas phase reactant comprising a rhenium precursor may include contacting the rhenium precursor with the substrate for about 0.01 seconds to about 60 seconds, about 0.05 seconds to about 10 seconds, or about 0.1 seconds to about 5.0 seconds. Further, during contacting the substrate with the rhenium precursor, the flow rate of the rhenium precursor can be less than 2000 sccm, or less than 500 sccm, or even less than 100 sccm. Further, during contacting the substrate with the rhenium precursor, the flow rate of the rhenium precursor can range from about 1 to 2000 sccm, about 5 to 1000 sccm, or about 10 to about 500 sccm.

[0072] The exemplary rhenium oxide formation process 100 of FIG. 1 may continue by purging the reaction chamber. For example, excess first gas phase reactant and reaction by-products, if any, may be removed from the surface of the substrate, for example, by pumping with an inert gas. In some embodiments of the present disclosure, the purging process may include a purge cycle, where the substrate surface is purged for a time period less than about 5.0 seconds, or less than about 3.0 seconds, or even less than about 2.0 seconds. For example, excess first gas phase reactant, such as excess rhenium precursor and possible reaction by-products, may be removed using a vacuum generated by a pumping system in fluid communication with the reaction chamber.

[0073] Upon purging the reaction chamber with a purge cycle, the exemplary rhenium oxide formation process 100 may continue with a second stage of the cyclical deposition phase 105 by process block 130 which includes contacting the substrate with a second gas phase reactant, in particular contacting the substrate with the second gas phase reactant comprising an oxygen-containing precursor ("oxygen precursor").

[0074] In some embodiments, the oxygen-containing precursor may include at least one of oxygen, ozone (O3), oxygen plasma, hydrogen peroxide (H2O2), water (H2O), or formic acid. In some embodiments, the rhenium precursor may include rhenium oxydifluoride (ReOF2) or rhenium dioxydichloride (ReOCl2), and the second vapor phase reactant may include water (H2O), ozone (O3), or hydrogen peroxide (H2O2). In some embodiments, the rhenium precursor may include rhenium oxytetrafluoride (ReOF4) or rhenium oxytetrachloride (ReOCl4), and the second vapor phase reactant may include water (H2O), ozone (O3), or hydrogen peroxide (H2O2).

[0075] In some embodiments of the present disclosure, the oxygen-containing precursor can include at least one of water (H2O), ozone (O3), hydrogen peroxide (H2O2), molecular oxygen (O2), atomic oxygen (O), sulfur trioxide (SO3), or an oxygen-based plasma, which includes atomic oxygen (O), oxygen ions, oxygen radicals, and excited oxygen species, and can be generated by excitation of an oxygen-containing gas (e.g., by application of RF power). It is noted that the term "gas-phase reactant" includes excited plasma and excited species that include plasma.

[0076] In some embodiments of the present disclosure, contacting the substrate with the oxygen-containing precursor can include contacting the oxygen precursor with the substrate for a time period between about 0.01 seconds and about 60 seconds, between about 0.05 seconds and about 10 seconds, or between about 0.1 seconds and about 5.0 seconds. Further, during contacting the substrate with the oxygen precursor, the flow rate of the oxygen precursor can be less than 2000 sccm, or less than 500 sccm, or even less than 100 sccm. Further, during contacting the substrate with the oxygen precursor, the flow rate of the oxygen precursor can range from about 1 to 2000 sccm, from about 5 to 1000 sccm, or from about 10 to about 500 sccm.

[0077] Upon contacting the substrate with the oxygen precursor, the exemplary rhenium oxide formation process 100 can proceed by purging the reaction chamber. For example, excess oxygen precursor and reaction by-products (if any) can be removed from the substrate surface, for example, by evacuating with a flow of inert gas. In some embodiments of the present disclosure, the purging process can include purging the substrate surface for about 0.1 seconds to about 10 seconds, or about 0.5 seconds to about 3 seconds, or even about 1 second to 2 seconds.

[0078] Upon completion of purging of the second gas phase reactant, i.e., the oxygen precursor (and reaction by-products) from the reaction chamber, the cyclical deposition phase 105 of the exemplary rhenium oxide formation process 100 continues at decision gate 140, which depends on the thickness of the deposited rhenium oxide film. For example, if the rhenium oxide film is deposited with an insufficient thickness for a desired device application, the cyclical deposition phase 105 may be repeated by returning to process block 120 and continuing with additional deposition cycles, where one unit of deposition cycle may include contacting the substrate with a rhenium precursor (process block 120), purging the reaction chamber, contacting the substrate with an oxygen-containing precursor (process block 130), and also purging the reaction chamber. The unit of deposition cycle of the cyclical deposition phase 105 may be repeated one or more times until a rhenium oxide film of a desired thickness is deposited on the substrate. Once the rhenium oxide film has been deposited to a desired thickness, the exemplary process 100 is terminated via process block 150, and the substrate with the rhenium oxide film deposited thereon may be subjected to further processing for the formation of a device structure.

[0079] In some embodiments of the present disclosure, the order of contacting the substrate with a first gas-phase reactant (e.g., a rhenium precursor) and a second gas-phase reactant (e.g., an oxygen precursor) can be such that the substrate is first contacted with the second gas-phase reactant, followed by the first gas-phase reactant. Further, in some embodiments, the cyclical deposition phase 105 of the exemplary process 100 can include contacting the substrate with the first gas-phase reactant one or more times before contacting the substrate with the second gas-phase reactant one or more times. Further, in some embodiments, the cyclical deposition phase 105 of the exemplary process 100 can include contacting the substrate with the second gas-phase reactant one or more times before contacting the substrate with the first gas-phase reactant one or more times.

[0080] As a non-limiting example, the reaction chamber may comprise an ALD reactor and the substrate may be heated to a temperature of approximately 200° C. (process block 110). The substrate may then be subjected to one or more deposition cycles of a cyclical deposition phase 105, which may include contacting the substrate with ReOF2, or ReOF4, and then contacting the substrate with water vapor or ozone to form a rhenium trioxide (ReO3) film.

[0081] As a further non-limiting example, the reaction chamber may comprise an ALD reactor and the substrate may be heated to a temperature of approximately 180° C. (process block 110). The substrate may then be subjected to one or more deposition cycles of a cyclical deposition phase 105, which may include contacting the substrate with ReOF5 and then contacting the substrate with water vapor to form a rhenium (VII) oxide (Re2O7) film.

[0082] In some embodiments, the substrate may then be subjected to one or more deposition cycles of a cyclical deposition phase 105, which may include contacting the substrate with ReOCl, or ReOF, and then contacting the substrate with oxygen, ozone, hydrogen peroxide, or water vapor to form a rhenium(IV) oxide (ReO2) film.

[0083] A further exemplary rhenium oxide formation process can be understood with reference to FIG. 2, which illustrates a cyclic deposition process 200 for the formation of a rhenium oxide film.

[0084] More specifically, the cyclic deposition process 200 may begin with process block 110, which includes providing a substrate into a reaction chamber and heating the substrate to a deposition temperature. Process block 110 has been described in detail with reference to FIG. 1 (cyclic deposition process 100), and therefore the details of process block 110 will not be repeated with respect to the cyclic deposition process 200.

[0085] Upon heating the substrate to a desired deposition temperature, in a suitable reaction chamber, the cyclic deposition process 200 may continue with a cyclic deposition phase 105 that includes cyclically depositing a rhenium oxide film to a desired thickness. The cyclic deposition phase 105 for depositing a rhenium oxide film has already been described in detail with reference to FIG. 1 (exemplary process 100) and will therefore be described in abbreviated form with respect to the cyclic deposition process 200. More specifically, the cyclic deposition phase 105 may include one or more cyclic deposition cycles, where a unit deposition cycle includes contacting the substrate with a rhenium precursor, purging excess rhenium precursor and any reaction by-products from the reaction chamber, contacting the substrate with an oxygen-containing precursor, and purging excess oxygen precursor and any reaction by-products from the reaction chamber.

[0086] As a non-limiting example, the cyclical deposition phase 105 may include depositing a rhenium oxide film, such as rhenium(VII) oxide (Re2O7), by contacting the substrate with a rhenium oxyfluoride, such as ReOF5, and contacting the substrate with water vapor (HO).

[0087] In some embodiments, the intermittent reduction step, i.e., contacting the deposited rhenium oxide film with a reducing agent precursor, may be applied after depositing a rhenium oxide film of a particular thickness. For example, a reduction step may be applied to the rhenium oxide film after depositing a rhenium oxide film of a thickness of about 0.5 angstroms, or after deposition of less than 1 nanometer, or after deposition of less than 3 nanometers, or after deposition of 5 nanometers or less, or even after deposition of more than 5 nanometers.

[0088] As a further non-limiting example, the cyclical deposition phase 105 may include depositing a rhenium oxide film, such as rhenium trioxide (ReO), by contacting the substrate with a rhenium oxyfluoride, such as ReOF, and contacting the substrate with water vapor (H0).

[0089] In embodiments of the present disclosure, the cyclical deposition phase 105 may be utilized to deposit a rhenium oxide film to a thickness of less than 1 Angstrom, or less than 2 Angstroms, or less than 5 Angstroms, or less than 10 Angstroms, or even less than 100 Angstroms. In embodiments of the present disclosure, the cyclical deposition phase 105 may be utilized to deposit a rhenium oxide film to a thickness that may be fully reduced by subsequently contacting the rhenium oxide film with a reducing agent precursor (the "reduction phase"), and in some alternative embodiments, the cyclical deposition phase 105 may be utilized to deposit a rhenium oxide film to a thickness that may be only partially reduced by subsequently contacting the rhenium oxide film with a reducing agent precursor.

[0090] In forming a rhenium oxide film to a desired thickness, the exemplary process 200 can proceed with a process block 220 that includes contacting the substrate and, in particular, contacting the rhenium oxide film with a reducing agent precursor. In some embodiments, the reducing agent precursor can include a dione, such as, for example, 2,5-hexanedione, cyclohexene-1,4-dione, or cyclohexanedione. In some embodiments, the reducing agent precursor can include an acid or a carboxylic acid, such as, for example, glyoxylic acid (OCHCO2H), formic acid (HCOOH), HCl, HF, HI, hydrogen halides such as HBr, or oxalic acid (COOH)2. In some embodiments, the reducing agent precursor can include ethylene oxide (C2H4O), or ethylene carbonate. In some embodiments, the reducing agent precursor can include an anhydride, such as, but not limited to, acetic anhydride (CH3CO)2O), phthalic anhydride, or maleic anhydride C2H2(CO)2O. In some embodiments, the reducing agent precursor may include carbon monoxide (CO), nitric oxide (NO), sulfur monoxide (SO), sulfur dioxide (SO2), hydrogen (H2), hydrazine (N2H4), forming gas (H2+N2), ammonia (NH3), or an ammonia-hydrogen (NH3-H2) mixture.

[0091] In some embodiments of the present disclosure, contacting the substrate with the reducing agent precursor may include contacting the reducing agent precursor with the substrate for about 0.01 seconds to about 60 seconds, about 0.05 seconds to about 10 seconds, or about 0.1 seconds to about 5.0 seconds. Further, during contacting the substrate with the reducing agent precursor, the flow rate of the reducing agent precursor can be less than 2000 sccm, or less than 500 sccm, or even less than 100 sccm. Further, during contacting the substrate with the reducing agent precursor, the flow rate of the reducing agent precursor can range from about 1 to 2000 sccm, about 5 to 1000 sccm, or about 10 to about 500 sccm.

[0092] As a non-limiting example, the cyclic deposition phase 105 of the exemplary process 200 may deposit a rhenium oxide (VII) (Re2O7) film to a thickness of less than about 100 angstroms, after which the rhenium oxide (VII) (Re2O7) film may be contacted with a reducing agent precursor, such as, but not limited to, carbon monoxide (CO), at a substrate temperature less than 250° C. for a time period greater than 1 second, or at a substrate temperature less than 350° C. for a time period greater than 100 seconds. For example, the reducing agent precursor may include carbon monoxide (CO), nitric oxide (NO), or sulfur monoxide (SO) vapor, and the reducing agent precursor may contact the rhenium oxide (VII) (Re2O7) film, thereby reducing the film to form a rhenium trioxide (ReO3) film.

[0093] As a further non-limiting example, the cyclic deposition phase 105 of the exemplary process 200 may deposit rhenium trioxide (ReO) to a thickness of less than about 1000 angstroms, or less than 500 angstroms, or less than 100 angstroms, or less than 10 angstroms, or even less than 1 angstrom, after which the rhenium trioxide (ReO) film may be reacted with, for example, but not limited to, carbon monoxide (CO), nitric oxide (NO), glyoxylic acid (OCHCOH), or other gases. ), 2,5-hexanedione, cyclohexene-1,4-dione, cyclohexanedione, sulfur dioxide (SO2), formic acid (HCOOH), acetic anhydride (CH3CO)2O, oxalic acid (COOH)2, or maleic anhydride C2H2(CO)2O, for less than 5 minutes, or less than 1 minute, or even less than 10 seconds, at a substrate temperature above 60° C., or at a substrate temperature above 120° C., or at a substrate temperature above 180° C., or even at a substrate temperature above 250° C. For example, the reducing agent precursor may include nitric oxide (NO) vapor, which may contact the rhenium trioxide (ReO3) film to reduce the film and form a rhenium(IV) oxide (ReO2) film.

[0094] In some embodiments, the entire rhenium oxide film deposited by cyclical deposition phase 105 can be reduced by contacting the rhenium oxide film with a reducing agent precursor, while in some alternative embodiments of the present disclosure, only a portion of the rhenium oxide film deposited by cyclical deposition phase 105 can be reduced by contacting the rhenium oxide film with a reducing agent precursor.

[0095] Upon contacting the substrate with the reducing agent precursor, the exemplary rhenium oxide formation process 200 can proceed by purging the reaction chamber. For example, excess reducing agent precursor and reaction by-products can be removed from the substrate surface, for example, by pumping in a flow of inert gas. In some embodiments of the present disclosure, the purging process can include purging the substrate surface for about 0.1 seconds to about 10 seconds, or about 0.5 seconds to about 3 seconds, or even about 1 second to about 2 seconds.

[0096] Upon completion of purging of excess reducing agent precursor (and any reaction by-products) from the reaction chamber, the exemplary rhenium oxide formation process 200 continues at decision gate 240, which depends on the thickness of the rhenium oxide film formed. For example, if the rhenium oxide film is formed with an insufficient thickness for a desired device application, the cyclical deposition phase 205 of the exemplary process 200 may be repeated by returning to the cyclical deposition phase 105 and continuing through one or more cyclical deposition cycles 205, where a unit deposition cycle of the cyclical deposition cycle 205 may include cyclically depositing a rhenium oxide film to a desired thickness (cyclical deposition phase 105), purging the reaction chamber, contacting the substrate with a reducing agent precursor (process block 220), and again purging the reaction chamber. A unit deposition cycle of the cyclical deposition phase 205 may be repeated one or more times until a rhenium oxide film of a desired thickness having a desired composition is formed on the substrate. Once the rhenium oxide film has been formed to a desired thickness and composition, the exemplary process 200 ends via process block 250, and the substrate with the rhenium oxide film formed thereon may be subjected to further processing to form a device structure.

[0097] A further exemplary rhenium oxide formation process may be understood with reference to FIG. 3, which illustrates a cyclic deposition process 300 for the formation of a rhenium oxide film.

[0098] More specifically, the cyclic deposition process 300 may begin with process block 110, which includes providing a substrate into a reaction chamber and heating the substrate to a deposition temperature. Process block 110 has been described in detail with reference to FIG. 1 (cyclic deposition process 100), and therefore the details of process block 110 will not be repeated with respect to the cyclic deposition process 300.

[0099] Once the substrate is heated to the desired deposition temperature in a suitable reaction chamber, cyclic deposition process 300 can continue utilizing either cyclic deposition phase 105 (process 100, FIG. 1) or cyclic deposition phase 205 (process 200, FIG. 2). Both cyclic deposition phase 105 and cyclic deposition phase 205 have already been described in detail, so cyclic deposition process 300 will be described in an abbreviated form.

[0100] More specifically, in some embodiments, the cyclical deposition phase 105 may be utilized to deposit rhenium oxide to a desired thickness and composition and may include one or more cyclical deposition cycles of the cyclical deposition phase 105, where a unit deposition cycle includes contacting the substrate with a rhenium precursor, purging excess rhenium precursor and any reaction by-products from the reaction chamber, contacting the substrate with an oxygen-containing precursor, and purging excess oxygen precursor and any reaction by-products from the reaction chamber. In some alternative embodiments, the cyclical deposition phase 205 may be utilized to deposit rhenium oxide to a desired thickness and composition and may include a unit cycle of the cyclical deposition phase 205, where a unit cycle may include cyclically depositing a rhenium oxide film to a desired thickness, purging excess precursor and any reaction by-products from the reaction chamber, contacting the substrate with a reducing agent precursor, and purging excess reducing agent precursor and any reaction by-products from the reaction chamber.

[0101] As a non-limiting example, a cyclical deposition phase 105 may be utilized by depositing a rhenium oxide film, such as rhenium trioxide (ReO), by contacting the substrate with a rhenium oxyfluoride, such as ReOF, and contacting the substrate with water vapor (H0).

[0102] As a further non-limiting example, the cyclical deposition phase 205 can be utilized to form a rhenium oxide film, such as, for example, rhenium trioxide (ReO), to a desired thickness by contacting rhenium trioxide (ReO) with a reducing agent precursor to form a rhenium (IV) oxide (ReO) film of the desired thickness.

[0103] In embodiments of the present disclosure, the cyclical deposition phases 105 and 205 may be utilized to deposit a rhenium oxide film to a thickness of less than 1000 angstroms, or less than 500 angstroms, or less than 100 angstroms, or even less than 10 angstroms. In embodiments of the present disclosure, the cyclical deposition phases 105 and 205 may be utilized to deposit a rhenium oxide film to a thickness that may be fully oxidized by subsequently contacting the rhenium oxide film with an additional oxygen-containing precursor, and in some alternative embodiments, the cyclical deposition phases 105 and 205 may be utilized to form a rhenium oxide film to a thickness that may be only partially oxidized by subsequently contacting the rhenium oxide film with an additional oxygen-containing precursor.

[0104] Once the rhenium oxide film is formed to a desired thickness and composition, the exemplary process 300 can proceed with process block 320 which includes contacting the substrate, and in particular contacting the rhenium oxide film with an additional oxygen-containing precursor.

[0105] In some embodiments of the present disclosure, the additional oxygen-containing precursor can include at least one of water (H2O), ozone (O3), formic acid (CHO2), hydrogen peroxide (H2O2), molecular oxygen (O2), atomic oxygen (O), sulfur trioxide (SO3), or an oxygen-based plasma, which includes atomic oxygen (O), oxygen ions, oxygen radicals, and excited oxygen species, and can be generated by excitation of an oxygen-containing gas (e.g., by application of RF power). It is noted that the term "gas-phase reactant" includes excited plasma and excited species that include plasma.

[0106] In some embodiments of the present disclosure, contacting the substrate with the additional oxygen-containing precursor can include contacting the additional oxygen precursor with the substrate for a time period between about 0.01 seconds and about 60 seconds, between about 0.05 seconds and about 10 seconds, or between about 0.1 seconds and about 5.0 seconds. Further, during contacting the substrate with the additional oxygen precursor, the flow rate of the additional oxygen precursor can be less than 2000 sccm, or less than 500 sccm, or even less than 100 sccm. Further, during contacting the substrate with the additional oxygen precursor, the flow rate of the additional oxygen precursor can range from about 1 to 2000 sccm, from about 5 to 1000 sccm, or from about 10 to about 500 sccm.

[0107] As a non-limiting example, the cyclic deposition phase 105 of the exemplary process 300 may be utilized to deposit a rhenium trioxide film (ReO3) to a thickness of less than about 1000 angstroms, or less than 500 angstroms, or less than 100 angstroms, or even less than 1 angstrom, after which the rhenium trioxide (ReO3) film may be contacted with an additional oxygen precursor, such as, for example, oxygen, water, an oxygen-containing plasma, ozone, acetic acid, or hydrogen peroxide, for a time period of 10 minutes or less, or less than 1 minute, or even less than 10 seconds, at a substrate temperature of less than 400° C., or less than 300° C., or less than 200° C., or even less than 100° C. For example, the additional oxygen-containing precursor may include ozone (O3), which may contact the rhenium trioxide film (ReO3) to oxidize the film to form a rhenium (VII) oxide (Re2O7) film.

[0108] As a further non-limiting example, the cyclic deposition phase 105 of the exemplary process 300 may be utilized to deposit a rhenium (IV) oxide (ReO) film to a thickness of less than about 1000 angstroms, or less than 500 angstroms, or less than 100 angstroms, or even less than 10 angstroms, after which the rhenium (IV) oxide (ReO) film may be contacted with an additional oxygen precursor, such as, for example, oxygen, water, an oxygen-containing plasma, ozone, acetic acid, or hydrogen peroxide, for a time period of 10 minutes or less, or less than 1 minute, or even less than 10 seconds, at a substrate temperature of less than 400° C., or less than 300° C., or less than 200° C., or even less than 100° C. For example, the additional oxygen-containing precursor may include hydrogen peroxide (H2O2), which may contact the rhenium (IV) oxide (ReO2) film to oxidize the film to form a rhenium (VII) oxide (Re2O7) film.

[0109] As a further non-limiting example, the cyclic deposition phase 205 of the exemplary process 300 may be utilized to form a rhenium (IV) oxide (ReO2) film to a thickness of less than about 1000 angstroms, or less than 500 angstroms, or less than 100 angstroms, and the rhenium (IV) oxide (ReO2) film may then be contacted with an additional oxygen precursor, such as, for example, oxygen, water, an oxygen-containing plasma, ozone, acetic acid, or hydrogen peroxide, for a time period of 10 minutes or less, or less than 1 minute, or even less than 10 seconds, at a substrate temperature of less than 400° C., or less than 300° C., or less than 200° C., or even less than 100° C. For example, the additional oxygen-containing precursor may include an oxygen-based plasma that may contact the rhenium (IV) oxide (ReO2) film to oxidize the film to form a rhenium (VII) oxide (Re2O7) film.

[0110] Thus, in some embodiments of the present disclosure, the rhenium oxide film comprises at least one of a rhenium (IV) oxide (ReO2) film, or a rhenium trioxide (ReO3) film, and the method of the present disclosure further comprises contacting the rhenium oxide film with an additional oxygen-containing precursor to form a rhenium (VII) oxide (Re2O7) film.

[0111] Once the substrate is contacted with the additional oxygen precursor, the exemplary rhenium oxide formation process 300 can proceed by purging the reaction chamber. For example, excess additional oxygen precursor and reaction by-products, if any, can be removed from the substrate surface, for example, by evacuating with a flow of inert gas. In some embodiments of the present disclosure, the purging process can include purging the substrate surface for about 1 second to about 100 seconds, or about 0.1 seconds to about 10 seconds, or about 0.5 seconds to about 3 seconds, or even about 1 second to 2 seconds.

[0112] Once purging of excess additional oxygen precursor (and any reaction by-products) from the reaction chamber is complete, the exemplary rhenium oxide formation process 300 continues at decision gate 340, which depends on the thickness of the rhenium oxide film formed. For example, if the rhenium oxide film is formed with an insufficient thickness for a desired device application, the cyclical deposition phase 305 may be repeated by returning to cyclical deposition phase 105 or 205 and continuing through cyclical deposition phase 305, where a unit deposition cycle of the cyclical deposition phase 305 may include forming a rhenium oxide film to a desired thickness and composition (cyclical phase 105 or 205), purging the reaction chamber, contacting the substrate with additional oxygen-containing precursor (process block 320), and purging the reaction chamber again. A unit deposition cycle of the cyclical deposition phase 305 may be repeated one or more times until a rhenium oxide film of a desired thickness having a desired composition is formed on the substrate. Once the rhenium oxide film is formed to the desired thickness and composition, the exemplary process 300 ends via process block 350, and the substrate with the rhenium oxide film formed thereon may be subjected to further processing to form a device structure.

[0113] In some embodiments of the present disclosure, the rhenium oxide film formed by the exemplary processes disclosed herein may include a dielectric material. For example, the rhenium (VII) oxide (Re2O7) film or the rhenium (IV) oxide (ReO2) film formed by the methods disclosed herein may include a dielectric material.

[0114] In some embodiments of the present disclosure, the rhenium oxide film formed by the exemplary processes disclosed herein may include a conductive rhenium oxide film. In some embodiments, the conductive phase of the rhenium oxide film may include a rhenium(IV) oxide (ReO2) or rhenium trioxide (ReO3) film. In some embodiments, the conductive rhenium oxide film has the general formula ReO xwhere x is less than 2. In some embodiments, the conductive phase of rhenium oxide films formed according to embodiments of the present disclosure can have an as-deposited electrical resistivity of less than 1000 μΩ-cm, or less than 700 μΩ-cm, or less than 500 μΩ-cm, or less than 250 μΩ-cm, or less than 100 μΩ-cm, or less than 50 μΩ-cm, or less than 25 μΩ-cm, or less than 10 μΩ-cm, or even less than 5 μΩ-cm. In some embodiments, the conductive phase of rhenium oxide films formed according to embodiments of the present disclosure can have an as-deposited electrical resistivity of between 5 μΩ-cm and 1000 μΩ-cm.

[0115] In some embodiments of the present disclosure, the rhenium oxide films formed according to embodiments of the present disclosure may be subjected to one or more additional processes to further improve the electrical resistivity of the rhenium oxide films.

[0116] More specifically, Figures 4A-4C depict cross-sectional schematic views of semiconductor structures formed utilizing an exemplary process for forming a low-resistance conductive rhenium oxide film. In some embodiments, methods of the present disclosure may include providing a substrate, such as substrate 400 of Figure 4A. Substrate 400 may include a non-planar or planar surface (as shown) and may further include one or more materials as previously disclosed with reference to process block 110 of Figure 1.

[0117] The substrate 400 may be placed in a suitable reaction chamber, such as, for example, an atomic layer deposition (ALD) reaction chamber, and heated to a desired deposition temperature. Once the substrate is heated to a desired deposition temperature, a rhenium oxide film 402 (FIG. 4B) may be deposited on the substrate 400 utilizing one of the exemplary processes 100 (FIG. 1), 200 (FIG. 2), or 300 (FIG. 3). In some embodiments, the rhenium oxide film 402 comprises a conductive rhenium oxide film. In some embodiments, the conductive rhenium oxide film 402 may comprise at least one of rhenium(IV) oxide (ReO2), or rhenium trioxide (ReO3). In some embodiments, the conductive rhenium oxide film may be formed of a material having the general formula ReO x where x is less than 2. In some embodiments, the conductive rhenium oxide film may be formed to a thickness of less than 1000 angstroms, or less than 500 angstroms, or less than 250 angstroms, or less than 100 angstroms, or less than 50 angstroms, or even less than 20 angstroms, and may have an electrical resistivity of less than 1000 μΩ-cm, or less than 500 μΩ-cm, or less than 100 μΩ-cm, or less than 50 μΩ-cm, or even less than 20 μΩ-cm.

[0118] In some embodiments of the present disclosure, the method of forming a low electrical resistivity conductive rhenium oxide film may further include forming a capping layer on the surface of the rhenium oxide film. For example, the capping layer 404 may be deposited directly on the upper exposed surface of the rhenium oxide film 402, thereby forming a semiconductor structure 406, as shown in FIG. 4C. In some embodiments, the capping layer 404 may include a conductive layer, such as titanium nitride (TiN), tantalum nitride (TaN), tantalum (Ta), tungsten carbide (WC), molybdenum (Mo), or niobium boride (NbB). While not wishing to be bound by any particular theory or mechanism, it is believed that adding a capping layer on the surface of the rhenium oxide film may prevent or substantially prevent sublimation of the rhenium oxide film.

[0119] Once the capping layer 404 is deposited on the surface of the rhenium oxide film 402, the method of the present disclosure may further include thermally annealing the rhenium oxide film 402. For example, the semiconductor structure 406 including the rhenium oxide film 402 may be thermally annealed at a temperature greater than 50° C., or greater than 100° C., or greater than 200° C., or greater than 300° C., or even greater than 400° C., or in a temperature range between 50° C. and 400° C. In some embodiments, thermally annealing the rhenium oxide film 402 may further include increasing the grain size of the crystals including the rhenium oxide film 402. In some embodiments, thermally annealing the rhenium oxide film 402 may further include forming a substantially single crystalline rhenium oxide film. In some embodiments, thermally annealing the rhenium oxide film 402 may further include reducing the density of grain boundaries within the rhenium oxide film. In some embodiments, thermally annealing the rhenium oxide film 402 may further include reducing the electrical resistivity of the rhenium oxide film. For example, the rhenium oxide film after thermal annealing may have an electrical resistivity of less than 1000 μΩ-cm, or less than 100 μΩ-cm, or less than 10 μΩ-cm.

[0120] Exemplary Cyclic Deposition Process for Forming Rhenium Sulfide Films In some embodiments of the present disclosure, the cyclic deposition process comprises a compound having the general formula ReS a Also Re x S y where a, x, and y are 7 or less, such as, for example, rhenium disulfide (ReS2), or dirhenium hepta sulfide (Re2S7). In some embodiments, the cyclic deposition process can include forming a rhenium sulfide film by a surface reaction between a first gas-phase reactant and a second gas-phase reactant. In some embodiments, the cyclic deposition process can include forming an intermediate rhenium oxide film, followed by contacting the intermediate rhenium oxide film with a sulfur-containing precursor.

[0121] An exemplary rhenium sulfide formation process may be understood with reference to FIG. 5, which illustrates an exemplary cyclic deposition process 500 for the formation of a rhenium sulfide film.

[0122] More specifically, the cyclic deposition process 500 may begin with process block 110, which includes providing a substrate into a reaction chamber and heating the substrate to a deposition temperature. Process block 110 has been described in detail with reference to FIG. 1 (cyclic deposition process 100), and therefore the details of process block 110 will not be repeated with respect to the cyclic deposition process 500.

[0123] Once the substrate is heated to the desired deposition temperature in a suitable reaction chamber, the cyclic deposition process 500 may continue with a cyclic deposition phase 505 process, which may begin via process block 120. Process block 120 has already been described in detail with reference to FIG. 1 (cyclic deposition process 100) and is therefore represented in abbreviated form with respect to the cyclic deposition process 500.

[0124] More specifically, process block 120 may include contacting the substrate with a rhenium precursor. In some embodiments, the rhenium precursor may include a rhenium halide, such as, for example, rhenium chloride, rhenium boride, rhenium fluoride, or rhenium iodide. In certain embodiments, the rhenium precursor may include a rhenium oxyhalide, such as, for example, rhenium oxyhalide or rhenium oxyfluoride. In some embodiments, the rhenium oxyhalide may be ReOF 4、 The rhenium precursor may include at least one of ReOF5, ReO2F2, or ReO2Cl3. In some embodiments, the rhenium precursor may include an alkyl rhenium oxide precursor, a cyclopentadienyl-based rhenium precursor, or a rhenium carbonyl halide precursor.

[0125] The exemplary rhenium sulfide formation process 500 of FIG. 5 may continue by purging the reaction chamber. For example, excess rhenium precursor and reaction by-products (if any) may be removed from the surface of the substrate, for example, by pumping in an inert gas. In some embodiments of the present disclosure, the purging process may include a purge cycle, where the substrate surface is purged for a time period less than about 5.0 seconds, or less than about 3.0 seconds, or even less than about 2.0 seconds. Excess rhenium precursor and possible reaction by-products may be removed using a vacuum generated by a pumping system in fluid communication with the reaction chamber.

[0126] The cyclical deposition phase 505 of the exemplary rhenium sulfide formation process 500 may continue with block 530, which includes contacting the substrate with a sulfur-containing precursor ("sulfur precursor"). In some embodiments, the sulfur-containing precursor includes at least one of hydrogen sulfide (HS), sulfur dioxide (SO), carbon disulfide (CS), dimethyl sulfide (CHS), methanethiol (CHSH), or a dialkyl disulfide.

[0127] In some embodiments of the present disclosure, contacting the substrate with the sulfur-containing precursor can include contacting the sulfur precursor with the substrate for a time period between about 0.01 seconds and about 60 seconds, between about 0.05 seconds and about 10 seconds, or between about 0.1 seconds and about 5.0 seconds. Furthermore, during contacting the substrate with the sulfur precursor, the flow rate of the sulfur precursor can be less than 2000 sccm, or less than 500 sccm, or even less than 100 sccm. Furthermore, during contacting the substrate with the sulfur precursor, the flow rate of the sulfur precursor can range from about 1 to 2000 sccm, from about 5 to 1000 sccm, or from about 10 to about 500 sccm.

[0128] The exemplary rhenium sulfide formation process 500 of FIG. 5 may continue by purging the reaction chamber. For example, excess sulfur precursor and reaction by-products (if any) may be removed from the surface of the substrate, for example, by pumping in an inert gas. In some embodiments of the present disclosure, the purging process may include a purge cycle, where the substrate surface is purged for a time period less than about 5.0 seconds, or less than about 3.0 seconds, or even less than about 2.0 seconds. Excess sulfur precursor and possible reaction by-products may be removed using a vacuum generated by a pumping system in fluid communication with the reaction chamber.

[0129] Upon completion of purging of excess sulfur precursor (and any reaction by-products) from the reaction chamber, the exemplary rhenium sulfide formation process 500 continues at decision gate 540, which depends on the thickness of the deposited rhenium sulfide film. For example, if the rhenium sulfide film has been deposited with an insufficient thickness for a desired device application, the cyclical deposition phase 505 may be repeated by returning to process block 120 and continuing with the cyclical deposition phase 505, where a unit deposition cycle of the cyclical deposition phase 505 may include contacting the substrate with a rhenium oxyhalide precursor (process block 120), purging the reaction chamber, contacting the substrate with a sulfur-containing precursor (process block 530), and also purging the reaction chamber. A unit deposition cycle of the cyclical deposition phase 505 may be repeated one or more times until a rhenium sulfide film having a desired composition and of a desired thickness is formed on the substrate. Once the rhenium sulfide film has been deposited to a desired thickness and composition, the exemplary process 500 ends via process block 550, and the substrate with the rhenium sulfide film formed thereon may be subjected to further processing to form a device structure.

[0130] It should be appreciated that in some embodiments of the present disclosure, the order of contacting the substrate with a first gas-phase reactant (e.g., a rhenium precursor) and a second gas-phase reactant (e.g., a sulfur precursor) can be such that the substrate is first contacted with the second gas-phase reactant followed by contact with the first gas-phase reactant. Additionally, in some embodiments, the cyclical deposition phase 505 of the exemplary process 500 can include contacting the substrate with the first gas-phase reactant one or more times before contacting the substrate with the second gas-phase reactant one or more times. Additionally, in some embodiments, the cyclical deposition phase 505 of the exemplary process 500 can include contacting the substrate with the second gas-phase reactant one or more times before contacting the substrate with the first gas-phase reactant one or more times.

[0131] As a non-limiting example, the reaction chamber may comprise an ALD reactor and the substrate may be heated to a temperature of about 100° C. to about 400° C. (process block 110). The substrate may then be subjected to one or more deposition cycles of a cyclical deposition phase 505, which may include contacting the substrate with ReO2F2 and then contacting the substrate with hydrogen sulfide (H2S) to form a rhenium disulfide (ReS2) film.

[0132] A further exemplary rhenium sulfide formation process may be understood with reference to FIG. 6, which illustrates a cyclic deposition process 600 for forming a rhenium sulfide film.

[0133] More specifically, the cyclic deposition process 600 may begin with process block 110, which includes providing a substrate into a reaction chamber and heating the substrate to a deposition temperature. Process block 110 has been described in detail with reference to FIG. 1 (cyclic deposition process 100), and therefore the details of process block 110 will not be repeated with respect to the cyclic deposition process 600.

[0134] Once the substrate is heated to the desired deposition temperature in a suitable reaction chamber, cyclic deposition process 600 can continue by forming a rhenium oxide film to the desired thickness and composition using either cyclic deposition phase 105 (process 100, FIG. 1), cyclic deposition phase 205 (process 200, FIG. 2), or cyclic deposition phase 305 (FIG. 3, process 300). Cyclic deposition phases 105, 205, and 305 have already been described in detail, and therefore details of cyclic deposition phases 105, 205, and 305 will not be repeated with respect to cyclic deposition process 600.

[0135] In some embodiments of the present disclosure, the cyclic deposition phase 105, 205, or 305 may be utilized to form a rhenium oxide film, such as, for example, a rhenium (IV) oxide (ReO2) film, a rhenium trioxide (ReO3), or a rhenium (VII) oxide (Re2O7) film. In some embodiments, the rhenium oxide film may be formed to a thickness of less than 1000 angstroms, or less than 500 angstroms, or less than 250 angstroms, or less than 100 angstroms, or even less than 10 angstroms.

[0136] In some embodiments of the present disclosure, the rhenium oxide may be formed to a thickness that may be completely converted to a rhenium sulfide film upon subsequent contacting of the rhenium oxide with a sulfur precursor, while in some alternative embodiments, the rhenium oxide may be formed to a thickness that may be only partially converted to a rhenium sulfide film upon subsequent contacting of the rhenium oxide with a sulfur precursor.

[0137] In some embodiments of the present disclosure, the cyclical deposition phase 605 may be continued by process block 620, which includes contacting the substrate with a sulfur-containing precursor ("sulfur precursor"). In some embodiments, the sulfur-containing precursor may include at least one of hydrogen sulfide (HS), sulfur dioxide (SO), carbon disulfide (CS), dimethyl sulfide (CHS), methanethiol (CHSH), or a dialkyl disulfide.

[0138] In some embodiments of the present disclosure, contacting the substrate, and in particular the rhenium oxide film, with a sulfur-containing precursor can include contacting the sulfur precursor with the substrate for a time period between about 0.01 seconds and about 60 seconds, between about 0.05 seconds and about 10 seconds, or between about 0.1 seconds and about 5.0 seconds. Furthermore, during contacting the substrate with the sulfur precursor, the flow rate of the sulfur precursor can be less than 2000 sccm, or less than 500 sccm, or even less than 100 sccm. Furthermore, during contacting the substrate with the sulfur precursor, the flow rate of the sulfur precursor can range from about 1 to 2000 sccm, from about 5 to 1000 sccm, or from about 10 to about 500 sccm.

[0139] The exemplary rhenium sulfide formation process 600 of FIG. 6 may continue by purging the reaction chamber. For example, excess sulfur precursor and reaction by-products (if any) may be removed from the surface of the substrate, for example, by pumping in an inert gas. In some embodiments of the present disclosure, the purging process may include a purge cycle, where the substrate surface is purged for a time period less than about 5.0 seconds, or less than about 3.0 seconds, or even less than about 2.0 seconds. Excess sulfur precursor and possible reaction by-products may be removed using a vacuum generated by a pumping system in fluid communication with the reaction chamber.

[0140] Once purging of excess additional sulfur precursor (and any reaction by-products) from the reaction chamber is complete, the exemplary rhenium sulfide formation process 600 continues at decision gate 640, which depends on the thickness of the rhenium sulfide film formed. For example, if the rhenium sulfide film is formed with an insufficient thickness for a desired device application, the cyclical deposition phase 605 may be repeated by returning to cyclical phases 105, 205, or 305 and continuing through cyclical deposition phase 605 to form a rhenium oxide film to a desired thickness and composition, where a unit deposition cycle of the cyclical deposition phase 605 may include forming a rhenium oxide film to a desired thickness and composition (cyclical phases 105, 205, or 305), purging the reaction chamber, contacting the substrate with a sulfur precursor (process block 640), and purging the reaction chamber again. A unit deposition cycle of the cyclical deposition phase 605 may be repeated one or more times until a rhenium sulfide film of a desired thickness having a desired composition is formed on the substrate. Once the rhenium sulfide film has been formed to a desired thickness and composition, the exemplary process 600 ends via process block 650, and the substrate with the rhenium sulfide film formed thereon may be subjected to further processing to form a device structure.

[0141] As a non-limiting example, the cyclic deposition phase 105 may be utilized in the cyclic deposition process 600 to deposit a rhenium trioxide film (ReO3) to a thickness of approximately less than 300 angstroms, after which the rhenium trioxide (ReO3) film may be contacted with a sulfur precursor, such as, for example, hydrogen sulfide (HS), sulfur monoxide (SO), sulfur dioxide (SO2), carbon disulfide (CS2), dimethyl sulfide (C2H6S), or methanethiol (CH3SH), for a time period of less than 10 minutes, or less than 5 minutes, or less than 1 minute, or even less than 10 seconds, at a substrate temperature ranging from 100° C. to 400° C., or from 150° C. to 300° C. For example, the sulfur-containing precursor may contact the rhenium trioxide film (ReO3), thereby converting the rhenium oxide film to rhenium disulfide (ReS2), dirhenium hepta sulfide (Re2S7), or a compound of the general formula ReS awhere a is a non-integer less than 3.5.

[0142] Exemplary Cyclic Deposition Process for Elemental Rhenium Film Formation In some embodiments of the present disclosure, a cyclic deposition process may be utilized to form an elemental rhenium film. In some embodiments, the cyclic deposition process may include forming an elemental rhenium film by a surface reaction between a first gas phase reactant and a second gas phase reactant. In some embodiments, the cyclic deposition process may include forming an intermediate rhenium oxide film, followed by contacting the intermediate rhenium oxide film with a hydrogen-containing precursor, thereby forming the elemental rhenium film.

[0143] An exemplary elemental rhenium formation process may be understood with reference to FIG. 7, which illustrates an exemplary cyclic deposition process 700 for the formation of an elemental rhenium film.

[0144] More specifically, the cyclic deposition process 700 may begin with process block 110, which includes providing a substrate into a reaction chamber and heating the substrate to a deposition temperature. Process block 110 has been described in detail with reference to FIG. 1 (cyclic deposition process 100), and therefore the details of process block 110 will not be repeated with respect to the cyclic deposition process 700.

[0145] Once the substrate is heated to the desired deposition temperature in a suitable reaction chamber, the cyclic deposition process 700 may continue with a cyclic deposition phase 705 process, which may begin via process block 120. Process block 120 has already been described in detail with reference to FIG. 1 (cyclic deposition process 100) and is therefore represented in abbreviated form with respect to the cyclic deposition process 700.

[0146] More specifically, process block 120 may include contacting the substrate with a rhenium precursor. In some embodiments, the rhenium precursor may include a rhenium halide, such as, for example, rhenium chloride, rhenium boride, rhenium fluoride, or rhenium iodide. In certain embodiments, the rhenium precursor may include a rhenium oxyhalide, such as, for example, rhenium oxyhalide or rhenium oxyfluoride. In some embodiments, the rhenium oxyhalide may be ReOF 4、 The rhenium precursor may include at least one of ReOF5, ReO2F2, or ReO2Cl3. In some embodiments, the rhenium precursor may include an alkyl rhenium oxide precursor, a cyclopentadienyl-based rhenium precursor, or a rhenium carbonyl halide precursor.

[0147] The exemplary elemental rhenium formation process 700 of FIG. 7 may continue by purging the reaction chamber. For example, excess rhenium precursor and reaction by-products (if any) may be removed from the surface of the substrate, for example, by pumping in an inert gas. In some embodiments of the present disclosure, the purging process may include a purge cycle, where the substrate surface is purged for a time period less than about 5.0 seconds, or less than about 3.0 seconds, or even less than about 2.0 seconds. Excess rhenium precursor and possible reaction by-products may be removed using a vacuum generated by a pumping system in fluid communication with the reaction chamber.

[0148] The cyclic deposition phase 705 of the exemplary elemental rhenium formation process 700 may continue with block 730, which includes contacting the substrate with a hydrogen-containing precursor ("hydrogen precursor"). In some embodiments, the hydrogen-containing precursor includes at least one of hydrogen sulfide (HS), molecular hydrogen (H), atomic hydrogen (H), hydrazine (NH), forming gas (H+N), ammonia (NH), an ammonia-hydrogen (NH-H) mixture, or a hydrogen-based plasma, which includes atomic hydrogen (H), hydrogen ions, hydrogen radicals, and excited hydrogen species, and may be generated by excitation of a hydrogen-containing gas (e.g., by applying RF power). It is noted that the term "gas-phase reactant" includes excited plasma and excited species that include plasma.

[0149] In some embodiments of the present disclosure, contacting the substrate with the hydrogen-containing precursor can include contacting the hydrogen precursor with the substrate for a time period between about 0.01 seconds and about 60 seconds, between about 0.05 seconds and about 10 seconds, or between about 0.1 seconds and about 5.0 seconds. Further, the flow rate of the hydrogen precursor during contacting the substrate with the hydrogen precursor can be less than 2000 sccm, or less than 500 sccm, or even less than 100 sccm. Further, the flow rate of the hydrogen precursor during contacting the substrate with the hydrogen precursor can range from about 1 to 2000 sccm, from about 5 to 1000 sccm, or from about 10 to about 500 sccm.

[0150] The exemplary elemental rhenium formation process 700 of FIG. 7 may continue by purging the reaction chamber. For example, excess hydrogen precursor and reaction by-products (if any) may be removed from the surface of the substrate, for example, by pumping in an inert gas. In some embodiments of the present disclosure, the purging process may include a purge cycle, where the substrate surface is purged for a time period less than about 5.0 seconds, or less than about 3.0 seconds, or even less than about 2.0 seconds. Excess hydrogen precursor and possible reaction by-products may be removed using a vacuum generated by a pumping system in fluid communication with the reaction chamber.

[0151] Once purging of excess hydrogen precursor (and any reaction by-products) from the reaction chamber is complete, the exemplary elemental rhenium formation process 700 continues at decision gate 740, which depends on the thickness of the elemental rhenium film formed. For example, if the elemental rhenium film is formed with an insufficient thickness for a desired device application, the cyclical deposition phase 705 may be repeated by returning to process block 120 and continuing with the cyclical deposition phase 705, where a unit deposition cycle of the cyclical deposition phase 705 may include contacting the substrate with a rhenium precursor (process block 120), purging the reaction chamber, contacting the substrate with a hydrogen-containing precursor (process block 730), and also purging the reaction chamber. The unit deposition cycle of the cyclical deposition phase 705 may be repeated one or more times until an elemental rhenium film of a desired thickness is formed on the substrate. Once the elemental rhenium film is deposited to a desired thickness, the exemplary process 700 ends via process block 750, and the substrate on which the elemental rhenium film is formed may be subjected to further processing for the formation of a device structure.

[0152] It will be appreciated that in some embodiments of the present disclosure, the order of contacting the substrate with a first gas phase reactant (e.g., a rhenium precursor) and a second gas phase reactant (e.g., a hydrogen precursor) can be such that the substrate is first contacted with the second gas phase reactant followed by contact with the first gas phase reactant. Additionally, in some embodiments, the cyclical deposition phase 705 of the exemplary process 700 can include contacting the substrate with the first gas phase reactant one or more times before contacting the substrate with the second gas phase reactant one or more times. Additionally, in some embodiments, the cyclical deposition phase 705 of the exemplary process 700 can include contacting the substrate with the second gas phase reactant one or more times before contacting the substrate with the first gas phase reactant one or more times.

[0153] As a non-limiting example, the reaction chamber may comprise an ALD reactor and the substrate may be heated to a temperature of approximately 150° C. to 300° C. (process block 110). The substrate may then be subjected to one or more deposition cycles of a cyclical deposition phase 705, which may include contacting the substrate with ReO2F2 and then contacting the substrate with a hydrogen-based plasma to form an elemental rhenium film.

[0154] A further exemplary elemental rhenium formation process may be understood with reference to FIG. 8, which illustrates an exemplary cyclic deposition process 800 for the formation of an elemental rhenium film.

[0155] More specifically, the cyclic deposition process 800 may begin with process block 110, which includes providing a substrate into a reaction chamber and heating the substrate to a deposition temperature. Process block 110 has been described in detail with reference to FIG. 1 (cyclic deposition process 100), and therefore the details of process block 110 will not be repeated with respect to the cyclic deposition process 800.

[0156] Once the substrate is heated to the desired deposition temperature in a suitable reaction chamber, cyclic deposition process 800 can continue by forming a rhenium oxide film to the desired thickness and composition using either cyclic deposition phase 105 (process 100, FIG. 1), cyclic deposition phase 205 (process 200, FIG. 2), or cyclic deposition phase 305 (FIG. 3, process 300). Cyclic deposition phases 105, 205, and 305 have already been described in detail, and therefore details of cyclic deposition phases 105, 205, and 305 will not be repeated with respect to cyclic deposition process 800.

[0157] In some embodiments of the present disclosure, the cyclical deposition phase 105, 205, or 305 may be utilized to form a rhenium oxide film, such as, for example, a rhenium (IV) oxide (ReO2) film, a rhenium trioxide (ReO3), or a rhenium (VII) oxide (Re2O7) film. In some embodiments, the rhenium oxide film is formed to a thickness of less than 1000 angstroms, or less than 500 angstroms, or less than 100 angstroms, or less than 10 angstroms, or even less than 5 angstroms.

[0158] In some embodiments of the present disclosure, the rhenium oxide may be formed to a thickness that may be subsequently converted completely to an elemental rhenium film by contacting the rhenium oxide with a sulfur precursor, while in some alternative embodiments, the rhenium oxide may be formed to a thickness that may be subsequently converted only partially to an elemental rhenium film by contacting the rhenium oxide with a hydrogen precursor.

[0159] In some embodiments of the present disclosure, the cyclical deposition phase 805 may be continued by process block 820, which includes contacting the substrate with a hydrogen-containing precursor ("hydrogen precursor"). In some embodiments, the hydrogen-containing precursor may include at least one of hydrogen sulfide (HS), hydrazine (NH), forming gas (H+N), ammonia (NH), an ammonia-hydrogen (NH-H) mixture, molecular hydrogen (H), atomic hydrogen (H), or a hydrogen-based plasma, which includes atomic hydrogen (H), hydrogen ions, hydrogen radicals, and excited hydrogen species, and may be generated by excitation of a hydrogen-containing gas (e.g., by applying RF power).

[0160] In some embodiments of the present disclosure, contacting the substrate, and in particular the rhenium oxide film, with a hydrogen-containing precursor can include contacting the hydrogen precursor with the substrate for a time period between about 0.01 seconds and about 60 seconds, between about 0.05 seconds and about 10 seconds, or between about 0.1 seconds and about 5.0 seconds. Further, the flow rate of the hydrogen precursor during contacting the substrate with the hydrogen precursor can be less than 2000 sccm, or less than 500 sccm, or even less than 100 sccm. Further, the flow rate of the hydrogen precursor during contacting the substrate with the hydrogen precursor can range from about 1 to 2000 sccm, from about 5 to 1000 sccm, or from about 10 to about 500 sccm.

[0161] The exemplary elemental rhenium film formation process 800 of FIG. 8 may continue by purging the reaction chamber. For example, excess hydrogen precursor and reaction by-products (if any) may be removed from the surface of the substrate, for example, by pumping in an inert gas. In some embodiments of the present disclosure, the purging process may include a purge cycle, where the substrate surface is purged for a time period less than about 5.0 seconds, or less than about 3.0 seconds, or even less than about 2.0 seconds. Excess hydrogen precursor and possible reaction by-products may be removed using a vacuum generated by a pumping system in fluid communication with the reaction chamber.

[0162] Once purging of excess hydrogen precursor (and any reaction by-products) from the reaction chamber is complete, the exemplary elemental rhenium formation process 800 continues at decision gate 840, which depends on the thickness of the elemental rhenium film formed. For example, if the elemental rhenium film is formed with an insufficient thickness for a desired device application, the cyclical deposition phase 805 may be repeated by returning to cyclical phases 105, 205, or 305 and continuing through the deposition cycle phase 805 to form a rhenium oxide film to a desired thickness and composition, where a unit deposition cycle of the cyclical deposition cycle 805 may include forming a rhenium oxide film to a desired thickness and composition (cyclical phases 105, 205, or 305), purging the reaction chamber, contacting the substrate with a hydrogen precursor (process block 820), and purging the reaction chamber again. A unit deposition cycle of the cyclical deposition phase 805 may be repeated one or more times until an elemental rhenium film of a desired thickness is formed on the substrate. Once the elemental rhenium film is formed to a desired thickness, the exemplary process 800 ends via process block 850, and the substrate with the elemental rhenium film formed thereon may be subjected to further processing to form a device structure.

[0163] As a non-limiting example, the cyclic deposition phase 105 may be utilized in the cyclic deposition process 800 to deposit a rhenium trioxide film (ReO3) to a thickness of less than 200 angstroms, after which the rhenium trioxide (ReO3) film may be contacted with a hydrogen precursor, such as, for example, hydrogen diatomic gas (H2), a hydrogen-containing plasma, ammonia (NH3), an ammonia-hydrogen mixture (NH3-H2), or forming gas (H2-N2), for a time period of less than 10 minutes, or less than 5 minutes, or less than 1 minute, or even less than 10 seconds, at a substrate temperature ranging from 80° C. to 400° C. For example, the hydrogen-containing precursor may include a hydrogen-based plasma that may contact the rhenium trioxide film (ReO3) and thereby convert the oxide film to form an elemental rhenium film.

[0164] Properties of rhenium-containing films formed by a cyclic deposition process In some embodiments of the present disclosure, the growth rate of the rhenium-containing film, such as, for example, an elemental rhenium film, a rhenium oxide film, a rhenium boride film, or a rhenium sulfide film, can be from about 0.005 angstroms / cycle to about 5 angstroms / cycle, from about 0.01 angstroms / cycle to about 2.0 angstroms / cycle. In some embodiments, the growth rate of the rhenium-containing film can be from about 0.1 angstroms / cycle to about 10 angstroms / cycle. In some embodiments, the growth rate of the rhenium-containing film is greater than about 0.05 angstroms / cycle, greater than about 0.1 angstroms / cycle, greater than about 0.15 angstroms / cycle, greater than about 0.20 angstroms / cycle, greater than about 0.25 angstroms / cycle, or even greater than about 0.3 angstroms / cycle. In some embodiments, the growth rate of the rhenium-containing film is less than about 2.0 Angstroms / cycle, or less than about 1.0 Angstroms / cycle, or less than about 0.75 Angstroms / cycle, or less than about 0.5 Angstroms / cycle, or less than 0.2 Angstroms / cycle. Some embodiments of the present disclosure may deposit rhenium-containing films at a growth rate of less than about 2.5 Angstroms / cycle, or even less than 1 Angstrom / cycle.

[0165] The rhenium-containing film deposited by the method disclosed herein can be a continuous film. In some embodiments, the rhenium-containing film can be continuous at a thickness of about 100 angstroms or less, or about 60 angstroms or less, or about 50 angstroms or less, or about 40 angstroms or less, or about 30 angstroms or less, or about 20 angstroms or less, or about 10 angstroms or less, or even about 5 angstroms or less. The continuity referred to herein can be physical continuity or electrical continuity. In some embodiments of the present disclosure, the thickness at which a material film may be physically continuous may not be the same as the thickness at which the film is electrically continuous, and vice versa.

[0166] In some embodiments of the present disclosure, the rhenium-containing films formed according to the embodiments of the present disclosure may have a thickness of about 20 nanometers to about 100 nanometers, or about 20 nanometers to about 60 nanometers. In some embodiments, the rhenium-containing films deposited according to some of the embodiments described herein may have a thickness of more than about 20 nanometers, or more than about 30 nanometers, or more than about 40 nanometers, or more than about 50 nanometers, or more than about 60 nanometers, or more than about 100 nanometers, or more than about 250 nanometers, or more than about 500 nanometers, or more. In some embodiments, the rhenium-containing films deposited according to some of the embodiments described herein may have a thickness of less than about 50 nanometers, or less than about 30 nanometers, or less than about 20 nanometers, or less than about 15 nanometers, or less than about 10 nanometers, or less than about 5 nanometers, or less than about 3 nanometers, or even less than about 2 nanometers. In some embodiments, the rhenium-containing film can have a thickness between about 0.1 nanometers and 50 nanometers, or between 1 nanometer and 30 nanometers, or between 4 nanometers and 20 nanometers.

[0167] In some embodiments of the present disclosure, rhenium-containing films can be formed on substrates including high aspect ratio features, such as three-dimensional, non-planar substrates, etc. In some embodiments, the step coverage of the rhenium-containing films can be about 50% or more, or about 80% or more, or about 90% or more, or about 95% or more, or about 98% or more, or about 99% or more, or more, on structures having aspect ratios (height / width) of 2 or more, or 5 or more, or 10 or more, or 25 or more, or 50 or more, or even 100 or more.

[0168] In some embodiments of the present disclosure, the rhenium-containing film may include pure rhenium, or rhenium and hydrogen, or rhenium, hydrogen and oxygen, or rhenium, hydrogen, carbon and oxygen, or rhenium, sulfur and oxygen. In some embodiments, the rhenium-containing film may further include impurities including, but not limited to, halides (e.g., chlorine, fluorine, iodine, or bromine), carbon, hydrogen, and nitrogen.

[0169] The rhenium-containing films formed by the embodiments of the present disclosure may be utilized in various technology applications. Non-limiting exemplary rhenium oxide films may be utilized as electrical interconnects, barrier layer films, as part of Schottky diode devices, as part of metal-insulator-semiconductor (MIS) devices, as part of metal-insulator-metal (MIM) devices, as part of gate electrodes for semiconductor devices such as NMOS or PMOS logic devices, as electrodes for semiconductor device structures such as DRAM devices. In addition, rhenium oxide films, such as rhenium(VII) oxide (Re2O7), may exhibit dielectric properties and thus may be utilized in DRAM devices and in capacitor structures. Furthermore, rhenium sulfides, such as rhenium disulfide (ReS2), may behave in a manner similar to 2D materials and may find applications in tribology, other low friction applications, solar cell applications, quantum computing, and ultra-high speed data processing.

[0170] As a non-limiting exemplary embodiment, the rhenium-containing film may include a conductive rhenium oxide film and may be utilized in semiconductor device structures including conductive interconnects for electrically connecting one or more semiconductor device structures.

[0171] More specifically, FIG. 9 illustrates a semiconductor device structure 900 that may include a substrate 902 that may include one or more semiconductor device structures (not shown) formed in or on a surface of the substrate. For example, the substrate 902 may include partially fabricated and / or fabricated semiconductor device structures, such as transistors and memory elements. The semiconductor device structure 900 may also include a dielectric material 904 formed on the substrate 902, which may include a low-k material, silicon oxide, silicon nitride, silicon oxynitride, or mixtures thereof. The semiconductor device structure 900 may further include a barrier material 906 that prevents or substantially prevents the conductive interconnect material 908 from diffusing into the surrounding dielectric material 904. In some embodiments of the present disclosure, the barrier material 906 may include a rhenium-containing material formed according to an embodiment of the present disclosure, such as, for example, a conductive rhenium oxide. The semiconductor device structure 900 may further include a conductive interconnect material 908 that may be utilized to electrically connect the semiconductor device structures formed in and / or on the substrate 902. In some embodiments of the present disclosure, the conductive interconnect material 908 may also include a rhenium-containing film formed according to an embodiment of the present disclosure. For example, the conductive interconnect material 908 may include a conductive rhenium oxide or elemental rhenium formed according to the methods disclosed herein. The semiconductor device structure 900 may also include a capping layer 910, such as a conductive capping layer including, for example, titanium nitride (TiN), tantalum nitride (TaN), or tungsten (W).

[0172] The embodiments of the present disclosure may also include a reaction system configured to form the rhenium-containing films of the present disclosure. More specifically, FIG. 10 illustrates a schematic of a reaction system 1000 comprising a reaction chamber 1002 for holding a substrate (not shown) under predetermined pressure, temperature, and environmental conditions, and further comprising mechanisms for selectively exposing the substrate to various gases. A precursor reactant source 1004 may be connected to the reaction chamber 1002 by a conduit or other suitable means 1004A, and may further be connected to a manifold, valve control system, mass flow control system, or mechanism for controlling the gaseous precursors originating from the precursor reactant source 1004. The precursors (not shown), reactants (not shown) provided by the precursor reactant source 1004 may be liquids or solids under room temperature and standard atmospheric pressure conditions. Such precursors may be vaporized in a vacuum vessel of the reactant source, and the precursors may be maintained above the vaporization temperature in the precursor source chamber. In such embodiments, the vaporized precursor may be transported in a carrier gas (e.g., an inactive or inert gas) and delivered into the reaction chamber 1002 through conduit 1004A. In other embodiments, the precursor may be gaseous under standard conditions. In such embodiments, the precursor does not need to be vaporized and does not require a carrier gas. For example, in one embodiment, the precursor may be stored in a gas cylinder.

[0173] As noted above, the reaction system 1000 may also include an additional precursor reactant source, such as a precursor reactant source 1006, which may be coupled to the reaction chamber by a conduit 1006A. As noted above, the reaction system may also include an additional precursor reactant source 1008, which may be coupled to the reaction chamber by a conduit 1008A. As noted, the reaction system may also include a further additional precursor reactant source 1009, which may be coupled to the reaction chamber by a conduit 1009A. In some embodiments of the present disclosure, the precursor reactant source 1004 may include a rhenium precursor, the precursor reactant source 1006 may include at least one of an oxygen-containing precursor, a sulfur-containing precursor, a boron-containing precursor, or a hydrogen-containing precursor, the precursor reactant source 1008 may include a reducing agent precursor, and the precursor reactant source 1009 may include an oxidizing precursor. Thus, in some embodiments of the present disclosure, the exemplary cyclical deposition processes 100, 200, 300, 500, 600, 700, and 800 of the present disclosure may be performed in a single reaction chamber.

[0174] A purge gas source 1010 is also coupled to the reaction chamber 1002 via conduit 1010A to selectively supply various inert or noble gases to the reaction chamber 1002 to assist in the removal of precursor or waste gases from the reaction chamber. The various inert or noble gases that may be supplied may come from solid, liquid or stored gaseous forms.

[0175] The reaction system 1000 of FIG. 10 may also include a system operation and control mechanism 1012 that provides electronic circuitry and mechanical components for selectively operating the valves, manifolds, pumps, and other devices included in the reaction system 1000. Such circuits and components operate to introduce precursors, their respective precursor sources 1004, 1006, 1008, 1009, and purge gas from a purge gas source 1010. The system operation and control mechanism 1012 also controls the timing of gas pulse sequences, substrate and reaction chamber temperatures, reaction chamber pressure, and various other operations required to properly operate the reaction system 1000. The operation and control mechanism 1012 may include control software and electrical or pneumatic control valves for controlling the flow of precursors, reactants, and purge gas into and out of the reaction chamber 1002. The control system may include software or hardware components, such as modules, such as FPGAs or ASICs, that perform specific tasks. The modules are advantageously configured to reside on an addressable storage medium of the control system and may be configured to perform one or more processes.

[0176] Those skilled in the relevant art will appreciate that other configurations of the present reaction system are possible, including different numbers and types of precursor reactant and purge gas sources. Moreover, such skilled artisans will also appreciate that there are many arrangements of valves, conduits, precursor sources, and purge gas sources that can be used to achieve the goal of selectively delivering gases into the reaction chamber 1002. Moreover, as a simplified illustration of the reaction system, many components are omitted for ease of illustration. Such components may include, for example, various valves, manifolds, purifiers, heaters, reservoirs, vents, and / or bypasses.

[0177] The exemplary embodiments of the present disclosure described above are merely examples of embodiments of the present invention, as defined by the appended claims and their legal equivalents, and therefore do not limit the scope of the present invention. Any equivalent embodiments are intended to be within the scope of the present invention. Indeed, various modifications of the present disclosure in addition to those shown and described herein may become apparent to those skilled in the art from the description, such as alternative useful combinations of the described elements. Such modifications and embodiments are also intended to fall within the scope of the appended claims.

Claims

1. 1. A method for forming a rhenium-containing film on a substrate by a cyclic deposition process, the method comprising: contacting the substrate with a first vapor phase reactant comprising a rhenium precursor selected from the group consisting of a rhenium oxyhalide precursor, an alkyl rhenium oxide precursor, a cyclopentadienyl-based rhenium precursor, or a rhenium carbonyl halide precursor; and contacting the substrate with a second gas phase reactant comprising a boron-containing precursor.

2. The method of claim 1 , wherein the rhenium-containing film comprises a rhenium boride film.

3. The method of claim 1 , wherein the rhenium oxyhalide comprises rhenium oxyfluoride.

4. The rhenium oxyfluoride is rhenium oxytetrafluoride (ReOF ４ ), rhenium oxypentafluoride (ReOF ５ ), rhenium dioxide difluoride (ReO ２ F ２ ), rhenium trioxyfluoride (ReO ３ F), rhenium dioxytrifluoride (ReO ２ F ３ ), rhenium oxydifluoride (ReOF ２ ), rhenium oxytrifluoride (ReOF ３ 4. The method of claim 3, further comprising at least one of: rhenium oxyfluoride (ReOF);

5. The method of claim 1 , wherein the rhenium oxyhalide comprises rhenium oxychloride.

6. The rhenium oxychloride is rhenium dioxytrichloride (ReO ２ C ３ ), rhenium oxytetrachloride (ReOCl ４ ), rhenium oxypentafluoride (ReOCl ５ ), rhenium trioxychloride (ReO ３ Cl), rhenium dioxide dichloride (ReO ２ C ２ ), rhenium oxydichloride (ReOCl ２ ), rhenium oxytrichloride (ReOCl ３ 6. The method of claim 5, further comprising at least one of the following: rhenium oxychloride (ReOCl);

7. The alkylrhenium oxide precursor is methylrhenium trioxide (CH ３ ReO ３ 2. The method of claim 1 , comprising:

8. 2. The method of claim 1, wherein the cyclopentadienyl-based rhenium precursor comprises at least one of a cyclopentadienyl rhenium hydride or a cyclopentadienyl rhenium carbonyl.

9. The rhenium carbonyl halide precursor is ReCl[CO] ５ The method of claim 8 , comprising:

10. The method of claim 1 , wherein the cyclical deposition process comprises an atomic layer deposition (ALD) process.

11. The method of claim 1 , wherein the cyclic deposition process comprises a cyclic chemical vapor deposition (CCVD) process.

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