Vapor deposition of gold-containing thin films

Abstract

Vapor deposition methods for forming a thin film comprising gold on a substrate in a reaction space are provided. The method may be a cyclic vapor deposition method, such as an atomic layer deposition (ALD) method. The method can include contacting the substrate with a gold precursor comprising at least one sulfur donor ligand and at least one alkyl ligand and contacting the substrate with a second reactant comprising ozone. The deposited gold-containing thin film can be uniform, continuous and conductive at very low thicknesses.

Description

[0001] This application is a divisional application of Chinese Invention Patent Application No. 201880008213.5 (Applicant: ASM IP Holdings Limited, Invention Title: Vapor Deposition of a Thin Film Containing Gold), filed on January 10, 2018. Technical Field

[0002] This disclosure generally relates to the field of vapor deposition, and in particular to the cyclic vapor deposition of thin films containing gold. Background Technology

[0003] Gold-containing thin films possess the electronic and plasmonic properties required for a wide range of applications across various fields, including photonics, MEMS devices, electronic components, electrochromic devices, photovoltaic devices, and photocatalysis. However, it has been shown that reliably depositing gold-containing thin films via cyclic vapor deposition is challenging, particularly for the deposition of continuous and conductive gold-containing films. Summary of the Invention

[0004] According to some embodiments, this document provides a method for forming a gold-containing thin film on a substrate in a reaction space. In some embodiments, the method may include alternately and sequentially contacting the substrate with a gaseous gold precursor and a gaseous second reactant, wherein the gaseous gold precursor comprises at least one ligand comprising sulfur or selenium and at least one alkyl ligand, and wherein the gold precursor and the second reactant react to form a gold-containing thin film.

[0005] In some embodiments, alternating and sequentially contacting the substrate with the vaporized gold precursor and the vaporized second reactant may include repeating deposition cycles two or more times. In some embodiments, the deposition cycle may further include removing excess vaporized gold precursor and reaction byproducts (if any) from the reaction space after contacting the substrate with the vaporized gold precursor. In some embodiments, the deposition cycle may further include removing excess second reactant and reaction byproducts (if any) from the reaction space after contacting the substrate with the second reactant.

[0006] According to some embodiments, the gold in the gold precursor has a +III oxidation state. In some embodiments, the ligand containing sulfur or selenium contains sulfur. In some embodiments, the ligand containing sulfur or selenium contains selenium. In some embodiments, the gold precursor contains one or more additional neutral adducts. In some embodiments, the gold precursor contains a diethyldithiocarbamate ligand. In some embodiments, the gold precursor contains Me₂Au(S₂CNEt₂). In some embodiments, the second reactant contains oxygen. In some embodiments, the second reactant contains a reactive species of oxygen. In some embodiments, the second reactant contains ozone.

[0007] According to some embodiments, the deposition temperature of the method is from about 120°C to about 220°C. In some embodiments, the gold-containing film is continuous when it reaches a thickness of about 20 nm.

[0008] In some embodiments, the gold-containing film has a thickness of about 20 nm to about 50 nm. In some embodiments, the gold-containing film has a resistivity of less than about 20 µΩcm. In some embodiments, the gold-containing film has a growth rate greater than about 0.8 Å per deposition cycle. In some embodiments, the method is atomic layer deposition (ALD). In some embodiments, the method is cyclic chemical vapor deposition (CVD).

[0009] According to some embodiments, an atomic layer deposition (ALD) method is provided for forming a gold-containing thin film on a substrate in a reaction space. In some embodiments, the method may include multiple deposition cycles, wherein at least one deposition cycle includes alternately and sequentially contacting the substrate with a vapor-phase gold precursor and a vapor-phase second reactant, wherein the deposition cycle is repeated two or more times to form a gold-containing thin film, wherein the gold in the vapor-phase gold precursor has a +III oxidation state and the vapor-phase gold precursor contains at least one sulfur donor ligand and at least one alkyl ligand.

[0010] According to some embodiments, the gold precursor comprises Me₂Au(S₂CNEt₂). In some embodiments, the second reactant comprises ozone. In some embodiments, the gold-containing film is continuous when it reaches a thickness of about 20 nm. In some embodiments, the gold-containing film is continuous after 100 deposition cycles. Attached Figure Description

[0011] The invention will be better understood from the detailed description and accompanying drawings, which are intended to illustrate and not limit the invention, and wherein:

[0012] Figure 1 is a process flow diagram, which generally illustrates the cyclic vapor deposition method used to deposit thin films containing gold.

[0013] Figure 2 is a process flow diagram, which roughly illustrates the atomic layer deposition method used to deposit thin films containing gold.

[0014] Figure 3 The thermogravimetric curve of Me2Au(S2CNEt2) is shown.

[0015] Figure 4A is a graph of the film growth rate versus deposition temperature for a gold-containing thin film deposited by a cyclic vapor deposition method as described herein and according to some embodiments.

[0016] Figure 4B is a graph showing the film thickness of a gold-containing thin film deposited at temperatures from 120°C to 200°C using a cyclic vapor deposition method as described herein and according to some embodiments, as a function of the distance between the film and the gold precursor inlet in the reaction chamber.

[0017] Figure 4C is a graph of the film resistivity versus deposition temperature of a gold-containing thin film deposited at temperatures from 120°C to 200°C by cyclic vapor deposition as described herein and according to some embodiments.

[0018] Figure 4D is an X-ray diffraction pattern of a gold-containing thin film deposited at a temperature of 120°C to 200°C by cyclic vapor deposition as described herein and according to some embodiments.

[0019] Figures 5A-D are scanning electron microscope (SEM) images of gold-containing thin films deposited at temperatures from 120°C to 200°C by cyclic vapor deposition as described herein and according to some embodiments.

[0020] Figure 6A is a graph showing the growth rate of a gold-containing thin film deposited at 180°C using a cyclic vapor deposition method as described herein and according to some embodiments, as a function of the gold precursor pulse length.

[0021] Figure 6B is a graph showing the film thickness of gold-containing films deposited by cyclic vapor deposition with gold precursor pulse lengths of 1 second and 2 seconds as described herein and according to some embodiments, as a function of the distance between the film and the gold precursor inlet in the reaction chamber.

[0022] Figure 6C is a graph of the thin film resistivity versus the gold precursor pulse length of a gold-containing thin film deposited by cyclic vapor deposition as described herein and according to some embodiments.

[0023] Figure 7A is a graph showing the thickness of a gold-containing thin film versus the number of deposition cycles deposited by a cyclic vapor deposition method as described herein and according to some embodiments.

[0024] Figures 7B-D are SEM images of gold-containing thin films deposited by cyclic vapor deposition with between 50 and 500 cycles, as described herein and according to some embodiments. Detailed Implementation

[0025] Gold-containing thin films, particularly continuous gold thin films deposited according to some embodiments described herein, have a wide range of potential applications. For example, in the field of plasma sensing, gold-containing thin films deposited according to some embodiments described herein can be used in surface-enhanced Raman spectroscopy (SERS). The unique plasmonic properties of gold-containing thin films make such films highly suitable for many next-generation electronic and photonic devices. Compared to other metal thin films, gold is also a highly efficient conductor and can carry very small currents while remaining relatively corrosion-free. Therefore, gold-containing thin films deposited according to some embodiments described herein can be used in a wide range of electronic components and device applications, including, for example, nanofabricated semiconductor devices.

[0026] Continuous and conductive gold-containing thin films deposited through some of the embodiments described herein can also be applied to microelectromechanical systems (MEMS) devices, such as radio frequency (RF) MEMS devices, because such films have high conductivity. RF MEMS devices incorporating continuous and conductive gold-containing thin films deposited through some of the embodiments described herein can operate at gigahertz frequencies, thereby allowing for large bandwidths and extremely high signal-to-noise ratios. Continuous gold-containing thin films deposited through some of the embodiments described herein can also be used in inertial MEMS to increase proof-mass quality and achieve high sensitivity in accelerometers. Such gold-containing thin films can be used in variable capacitors, chemical and biological sensors, and optical detectors.

[0027] The gold-containing thin films deposited according to the method described herein can also be used in applications such as electrochromic devices, photovoltaic cells, and photocatalysis.

[0028] According to some embodiments, gold-containing thin films and methods for forming gold-containing thin films are provided. In some embodiments, the gold-containing thin films deposited according to the methods described herein may be metallic and may be continuous and conductive.

[0029] In some embodiments, the gold-containing thin film is deposited on a substrate by vapor deposition. For example, in some embodiments, the gold-containing thin film can be deposited by a surface-controlled reaction deposition method, wherein a gold precursor on the substrate reacts with a second reactant to form a gold-containing film, such as in atomic layer deposition methods. In some embodiments, the vapor deposition method can be a thermal deposition method.

[0030] In some embodiments, the vapor deposition method may be plasma deposition. However, in some embodiments, the vapor deposition method does not employ plasma. In some embodiments, the deposition method may be a cyclic deposition method, such as atomic layer deposition (ALD) or cyclic chemical vapor deposition (CVD). In some embodiments, the method for depositing a gold-containing thin film may include alternately and continuously contacting a substrate with a first vapor-phase gold reactant and a second reactant.

[0031] In some embodiments, the deposition method may employ an organometallic gold precursor and a second reactant. In some embodiments, the gold in the organometallic gold precursor may have an oxidation state of +III. In some embodiments, the organometallic gold precursor may contain sulfur. In some embodiments, the organometallic gold precursor contains at least one sulfur-containing ligand and at least one alkyl ligand. For example, when a gold precursor is used in a method as described herein and the gold precursor does not contain at least one sulfur-containing ligand and at least one alkyl ligand, such a method may not deposit a continuous film containing gold, or may only produce a continuous film at high film thicknesses. Therefore, it has been unexpectedly found that employing a gold precursor containing at least one sulfur-containing ligand and at least one alkyl ligand, such as a gold precursor containing Me2Au(S2CNEt2), allows for the deposition of high-quality thin films containing gold at relatively low film thicknesses, for example, continuous gold films with relatively low film thicknesses. In some embodiments, the organometallic gold precursor may contain Me2Au(S2CNEt2). In some embodiments, the second reactant may contain oxygen. In some embodiments, the second reactant may comprise a reactive form of oxygen, such as ozone. In some embodiments, the method for depositing a gold-containing thin film may employ a gold precursor comprising at least one sulfur-containing ligand, at least one alkyl ligand ( wherein the gold in the gold precursor is in the +III oxidation state), and a second reactant comprising ozone.

[0032] In some embodiments, the deposited film may contain gold. In some embodiments, a film containing metallic gold may be deposited. In some embodiments, the deposited gold-containing film may contain a certain amount of oxygen. In some embodiments, the deposited gold-containing film may be continuous. In some embodiments, the deposited gold-containing film may be continuous at a thickness of less than about 50 nm, less than about 40 nm, less than about 30 nm, or less than about 20 nm or less. In some embodiments, the continuous gold-containing film may be deposited by a deposition method comprising less than about 500 deposition cycles, less than about 400 deposition cycles, less than about 300 deposition cycles, less than about 200 deposition cycles, or less than about 100 deposition cycles or less.

[0033] In some embodiments, the deposited gold-containing film may be a conductive film. In some embodiments, the deposited gold-containing film may have a resistivity of less than about 20 µΩcm, less than about 15 µΩcm, less than about 10 µΩcm, less than about 5 µΩcm, or even less.

[0034] Vapor deposition of thin films containing gold

[0035] In some embodiments, the vapor deposition method may be a thermal deposition method. Atomic layer deposition (ALD) type methods are based on controlled, self-limiting surface reactions of precursor chemicals or reactants. Gas-phase reactions are avoided by alternately and sequentially contacting the substrate with the precursors. For example, gas-phase reactants are separated from each other on the substrate surface by removing excess reactants and / or reactant byproducts from the substrate surface of interest between reactant pulses. In some embodiments, one or more substrate surfaces are alternately and sequentially contacted with two or more gas-phase precursors or reactants. Contacting the substrate surface with gas-phase reactants refers to a limited period of time during which reactant vapors are in contact with the substrate surface. In other words, it can be understood that the substrate surface is exposed to each gas-phase reactant for a limited period of time.

[0036] In short, the substrate is typically heated to a suitable deposition temperature under reduced pressure. The deposition temperature is generally maintained below the thermal decomposition temperature of the reactants, but at a level high enough to avoid reactant condensation and to provide the activation energy for the desired surface reaction. Of course, the appropriate temperature window for any given ALD reaction will depend on the surface termination state and reactant species involved. Here, the temperature varies depending on the precursors used and is generally at or below about 700°C. In some embodiments, for vapor deposition, the deposition temperature is generally at or above about 100°C; in some embodiments, the deposition temperature is between about 100°C and about 250°C; and in some embodiments, the deposition temperature is between about 120°C and about 200°C. In some embodiments, the deposition temperature is below about 500°C, below about 400°C, or below about 300°C. In some cases, for example, if additional reactants or reducing agents, such as those containing hydrogen, are used in the process, the deposition temperature may be below about 200°C, below about 150°C, or below about 100°C.

[0037] The surface of the substrate is brought into contact with a first gaseous reactant or precursor. In some embodiments, a pulse of the gaseous first reactant is supplied to the reaction space containing the substrate (e.g., in a time-divided ALD). In some embodiments, the substrate is moved to a reaction space containing the gaseous first reactant (e.g., in a spatially divided ALD, also known as a spatial ALD). Options may be chosen such that no more than about one monolayer of the first reactant or its species is adsorbed in a self-limiting manner onto the first surface of the substrate. However, in some arrangements, mixed CVD / ALD or cyclic CVD methods allow different interacting reactants to overlap on the substrate and thus more than one monolayer can be produced per cycle. A suitable contact time can be readily determined by those skilled in the art based on specific circumstances. Excess first reactant and reaction byproducts (if any) are removed from the substrate surface, for example, by purging with an inert gas or by removing the substrate from the presence of the first reactant.

[0038] For ALD processes where overlap between reactants is minimized or avoided, gaseous precursors and / or gaseous byproducts are removed from the substrate surface, such as by evacuating the chamber with a vacuum pump and / or by purging (e.g., replacing the gas in the reactor with an inert gas such as argon or nitrogen). During removal, the supply of reactants to the substrate surface is typically stopped, and reactants can be diverted to different chambers or to the vacuum pump during removal. Typical removal times are approximately 0.05 to 20 seconds, approximately 1 to 10 seconds, or approximately 1 to 2 seconds. However, other removal times may be used if desired, such as when high conformal step coverage is required on structures with extremely high aspect ratios or other structures with complex surface morphologies.

[0039] The substrate surface is brought into contact with a gaseous second reactant or precursor. In some embodiments, a pulse of the second reactant is supplied to a reaction space containing the substrate. In some embodiments, the substrate is moved to a reaction space containing the gaseous second reactant. If applicable, excess second reactant and gaseous byproducts of the surface reaction are removed from the substrate surface. Contact and removal are repeated until a film of the desired thickness is formed on the substrate, leaving no more than about one molecular monolayer per cycle in ALD or ALD-type methods, or one or more molecular monolayers per cycle in hybrid CVD / ALD or cyclic CVD methods. Additional stages, including alternating and sequential contact of the substrate surface with other reactants, may be introduced to form more complex materials, such as alloys containing two or more metals, or composite materials containing gold and some other one or more compounds.

[0040] As described above, for the ALD method, each stage of each cycle can be self-limiting. An excess of reactant is supplied in each stage to saturate the susceptible substrate surface. Surface saturation ensures that the reactant occupies all available reaction sites (e.g., limited by physical size or "steric hindrance") and thus ensures excellent step coverage. Typically, less than one molecular layer of material is deposited per cycle; however, in some embodiments, more than one molecular layer is deposited during cycling.

[0041] Removing excess reactants may include evacuating some of the contents of the reaction space and / or purging the reaction space with helium, nitrogen, argon, or another inert gas. In some embodiments, purging may include disconnecting the flow of the reactant gas while the inert carrier gas continues to flow into the reaction space. For example, in some embodiments, the inert carrier gas may be allowed to flow continuously throughout the deposition process, while the precursors or reactants may be supplied to the reaction space intermittently.

[0042] The substrate can comprise various types of materials. When fabricating integrated circuits, the substrate typically comprises multiple thin films with different chemical and physical properties. In some embodiments, the substrate may comprise silicon or silicon oxide, such as native or thermal oxides. In some embodiments, the substrate may comprise glass. In some embodiments, the substrate may comprise one or more oxide materials, such as metal oxide materials. In some embodiments, the substrate may comprise dielectric materials. In some embodiments, the substrate may comprise metals or metal films, such as metal nitrides, metal carbides, metal silicides, or mixtures thereof. In some embodiments, the substrate may be a semiconductor substrate. In some embodiments, the substrate may comprise one or more three-dimensional structures. In some embodiments, one or more structures may have an aspect ratio of 1:1 to 10:1 or greater. In some embodiments, the substrate may comprise integrated circuit artifacts. In some embodiments, the substrate does not comprise a semiconductor substrate or wafer.

[0043] In vapor deposition, the precursor used can be a solid, liquid, or gaseous material under standard conditions (room temperature and atmospheric pressure), provided that the precursor is in the gaseous phase before contacting the substrate surface. Contact between the substrate surface and the evaporated precursor refers to a limited period of time during which the precursor vapor contacts the substrate surface. Typically, the contact time is approximately 0.05 to 10 seconds. However, depending on the substrate type, its surface area, and / or the size of the chamber, the contact time can even exceed 10 seconds. In some cases, the contact time can be several minutes, especially for batch deposition on multiple substrates. A skilled technician can easily determine the optimal contact time based on the specific circumstances.

[0044] The mass flow rate of the precursor can also be determined by a skilled technician. In some embodiments, for single-wafer deposition reactors, the precursor flow rate is, without limitation, between about 1 and 1000 sccm, more particularly between about 100 and 500 sccm. In some embodiments, the flow rate may be less than 100 sccm, less than 75 sccm, or less than 50 sccm.

[0045] The pressure in the reaction chamber is typically from about 0.01 mbar to about 20 mbar or from about 1 mbar to about 10 mbar. In some embodiments, the reaction chamber pressure may be from about 0.01 mbar to about atmospheric pressure. Before starting film deposition, the substrate is typically heated to a suitable growth temperature. The growth temperature varies depending on the type of film formed, the chemical and physical properties of the precursor, etc. The growth temperature may be below the crystallization temperature of the deposited material, resulting in the formation of an amorphous film, or above the crystallization temperature, resulting in the formation of a crystalline film. The deposition temperature can vary with many factors, such as, but not limited to, the reactant precursor, pressure, flow rate, reactor arrangement, the crystallization temperature of the deposited film, and the composition of the substrate, including the properties of the material to be deposited thereon. A skilled artisan can select a specific growth temperature.

[0046] In some embodiments, the substrate temperature is high enough to support thermal ALD of the reactants of interest. For example, the substrate temperature is typically above about 100°C and at or below about 700°C. In some embodiments, the substrate temperature is between about 100°C and about 250°C, and in some embodiments, the substrate temperature is between about 120°C and about 200°C. In some embodiments, the substrate temperature is below about 500°C, below about 400°C, or below about 300°C. In some cases, the substrate temperature may be below about 200°C, below about 150°C, or below about 100°C.

[0047] In some embodiments, a gold-containing thin film can be formed on a substrate by a method comprising at least one deposition cycle, said deposition cycle comprising alternately and sequentially contacting the substrate with a vapor-phase gold precursor and a vapor-phase second reactant. In some embodiments, the deposition cycle may be repeated two or more times. In some embodiments, the deposition cycle may be sequentially repeated two or more times. In some embodiments, excess gold precursor and reaction byproducts (if any) may be removed after contacting the substrate with the vapor-phase gold precursor and before contacting the substrate with the vapor-phase second reactant. In some embodiments, excess second reactant and reaction byproducts (if any) may be removed after contacting the substrate with the vapor-phase gold precursor and before starting another deposition cycle. In some embodiments, the substrate may be contacted with a purge gas after contacting the substrate with the vapor-phase gold precursor and before contacting the substrate with the vapor-phase second reactant. In some embodiments, the substrate may be contacted with a purge gas after contacting the substrate with the vapor-phase second reactant and before starting another deposition cycle.

[0048] The gold-containing thin films formed according to some embodiments are between about 20 nm and about 50 nm thick; however, the selected actual thickness may be chosen based on the intended application of the film. In some embodiments, it is desirable to ensure that all or most of the target substrate surface is covered by the gold-containing thin film. In some embodiments, it is desirable to form a continuous gold-containing film. In such cases, it may be desirable to form a gold-containing film at least about 10 nm thick, at least about 20 nm thick, at least about 30 nm thick, at least about 40 nm thick, or at least about 50 nm thick. In some embodiments, a thickness greater than 50 nm may be required, for example, greater than 100 nm, greater than 250 nm, or greater than 500 nm or greater. However, in some other embodiments, it may be desirable to form a discontinuous gold-containing thin film, or a film comprising individual islands or nanoparticles containing gold.

[0049] In some embodiments, it may be desirable to form a gold-containing film with a certain number of deposition cycles, such as more than about 50 cycles, more than about 100 cycles, more than about 250 cycles, or more than about 500 cycles or more. In some embodiments, the deposition method may include any number of deposition cycles.

[0050] Deposition can be performed using reactors capable of growing thin films. Such reactors include ALD reactors and CVD reactors equipped with suitable equipment and measures for providing precursors. According to some embodiments, spray head reactors may be used.

[0051] Examples of suitable reactors that can be used include commercially available single-substrate (or single-wafer) deposition equipment, such as Pulsar® reactors (e.g., Pulsar® 2000, Pulsar® 3000, and Pulsar® XP ALD) and EmerALD® reactors, available from ASM America, Inc. of Phoenix, Arizona, USA, and ASM Europe BV of Almere, Netherlands. Other commercially available reactors include those available under the trade names Eagle® XP and XP8 from ASM Japan KK (Tokyo, Japan).

[0052] In some embodiments, a batch reactor may be used. Suitable batch reactors include, but are not limited to, the Advance® 400 series reactors, commercially available from ASMEurope BV (Almere, Netherlands), under the trade names A400 and A412 PLUS. In some embodiments, a vertical batch reactor, such as the A412, is employed in which the wafers rotate during processing. Thus, in some embodiments, the wafers rotate during processing. In other embodiments, the batch reactor comprises a small batch reactor configured to accommodate 10 or fewer wafers, eight or fewer wafers, six or fewer wafers, four or fewer wafers, or two wafers. In some embodiments where a batch reactor is used, the inter-wafer inhomogeneity is less than 3% (1 sigma), less than 2%, less than 1%, or even less than 0.5%.

[0053] The deposition method described herein can optionally be carried out in a reactor or reaction space connected to a clustering tool. In a clustering tool, since each reaction space is dedicated to one type of process, the temperature of the reaction space in each module can be kept constant, which improves throughput compared to a reactor where the substrate is heated to the process temperature before each operation. Additionally, in a clustering tool, it is possible to reduce the time required to pressurize the reaction space to the process pressure level needed between the substrates using pumps.

[0054] Independent reactors can be equipped with loading locks. In this case, it is not necessary to cool the reaction space between runs. In some embodiments, the deposition method for depositing thin films containing gold may include multiple deposition cycles, such as an ALD cycle.

[0055] In the second stage, the substrate is brought into contact with a second reactant, such as a second reactant containing ozone, which can convert the adsorbed first precursor into gold material. Bringing the substrate into contact with the second reactant and subsequently removing excess second reactant and reaction byproducts (if any) from the substrate surface can be considered a stage and may be referred to as the second stage, the second reactant stage, the second precursor stage, etc.

[0056] One or more precursors may be provided using a carrier gas such as N2, Ar, or He. Additional stages may be added and certain stages may be removed as needed to adjust the composition of the final membrane. The terms "first" and "second" may be applied to any particular precursor or reactant, depending on the sequence of any particular embodiment. For example, depending on the embodiment, the first reactant may be either a gold precursor or a second reactant.

[0057] Referring to Figure 1 and according to some embodiments, a thin film containing gold is deposited on a substrate in a reaction space by a cyclic vapor deposition method 100 comprising at least one deposition cycle, said deposition cycle comprising:

[0058] At frame 110, the surface of the substrate is brought into contact with a gaseous gold precursor containing at least one sulfur donor ligand (i.e., a ligand bonded to a gold atom via a sulfur atom) and at least one alkyl ligand.

[0059] Remove any excess gold precursors and reaction byproducts (if any) from the surface at box 120;

[0060] At frame 130, the surface of the substrate is brought into contact with the gaseous second reactant;

[0061] Remove any excess second reactant and reaction byproducts (if any) from the surface of the substrate at box 140; and

[0062] Optionally repeat the contact and removal steps at frame 150 to form a gold-containing film of the desired thickness.

[0063] In some embodiments, the cyclic deposition method 100 described above can be an ALD-type method. In some embodiments, the cyclic deposition method 100 can be an ALD method. In some embodiments, the cyclic deposition method 100 described above can be a hybrid ALD / CVD or cyclic CVD method.

[0064] While the illustrated deposition cycle begins by contacting the substrate surface with the vapor gold precursor, in other embodiments, the deposition cycle may begin by contacting the substrate surface with a second reactant. Those skilled in the art will understand that if the substrate surface contacts the first precursor and the precursor does not react, the process will begin by providing the next precursor.

[0065] In some embodiments, removal of precursors or reactants and any excess reaction byproducts at frames 120 and 140 may include purging the reaction space or reaction chamber. Purging the reaction chamber may include using a purge gas and / or applying a vacuum to the reaction space. When using a purge gas, the purge gas may flow continuously through the reaction space or may flow only after the flow of the reactant gas has stopped and before the next reactant gas begins to flow through the reaction space. It is also possible to continuously flow the purge or non-reactive gas through the reaction chamber to utilize the non-reactive gas as a carrier gas for various reactive species. Thus, in some embodiments, a gas such as nitrogen flows continuously through the reaction space, while the gold precursor and the second reactant are pulsed into the reaction chamber as needed. Because the carrier gas is continuously flowing, the removal of excess reactants or reaction byproducts can be achieved simply by stopping the flow of reactant gas into the reaction space.

[0066] In some embodiments, removal of precursors or reactants and any excess reaction byproducts at frames 120 and 140 may include moving the substrate from the first reaction chamber to a second, different reaction chamber containing purge gas. In some embodiments, removal of precursors or reactants and any excess reaction byproducts at frames 120 and 140 may include moving the substrate from the first reaction chamber to a second, different reaction chamber under vacuum. In some embodiments, removal of precursors or reactants and any excess reaction byproducts at frames 120 and 140 may include moving the substrate from a first precursor region to a second, different precursor region. These two regions may be separated, for example, by a buffer containing purge gas and / or vacuum.

[0067] In some embodiments, the deposited gold-containing film may be subjected to a processing step after deposition. In some embodiments, this processing step may, for example, enhance the conductivity or continuity of the gold-containing deposited film. In some embodiments, the processing step may include, for example, an annealing process. In some embodiments, the gold-containing film may be annealed in an atmosphere containing one or more annealing gases, such as a hydrogen-containing gas.

[0068] Referring to Figure 2 and according to some embodiments, a thin film containing gold is deposited on a substrate in a reaction space by an atomic layer deposition method 200 comprising at least one deposition cycle, said deposition cycle comprising:

[0069] At frame 210, the surface of the substrate is brought into contact with a vapor-phase gold precursor containing Me2Au(S2CNEt2);

[0070] Remove any excess gold precursors and reaction byproducts (if any) from the surface at box 220;

[0071] At frame 230, the surface of the substrate is brought into contact with a gaseous second reactant containing ozone;

[0072] Remove any excess oxygen reactants and reaction byproducts (if any) from the surface of the substrate at box 240; and

[0073] Optionally repeat the contact and removal steps at frame 250 to form a gold-containing film of the desired thickness.

[0074] In some embodiments, a gold-containing thin film is formed on a substrate using an ALD-type method comprising at least one deposition cycle, said deposition cycle including:

[0075] The surface of the substrate is brought into contact with a gaseous gold precursor comprising at least one sulfur donor ligand and at least one alkyl ligand to form at most one molecular monolayer of the gold precursor or a species thereof on the substrate;

[0076] Remove excess gold precursors and reaction byproducts from the surface;

[0077] The surface of the substrate is brought into contact with a gaseous second reactant containing ozone;

[0078] Remove any excess of the second reactant from the surface and any gaseous byproducts formed in the reaction between the gold precursor layer and the ozone-containing second reactant.

[0079] The contact and removal steps can be repeated until a gold-containing film of the desired thickness is formed.

[0080] In some embodiments, the gold-containing thin film deposition method may further include subjecting the substrate to a pretreatment process before contacting the substrate with a first vapor-phase gold precursor. In some embodiments, the pretreatment process may include exposing the substrate to a pretreatment reactant. In some embodiments, the pretreatment reactant may remove unwanted contaminants or prepare a surface for subsequent deposition of the gold-containing thin film. In some embodiments, the pretreatment reactant may contain, for example, HCl, HF, or reactive species such as plasma.

[0081] gold precursor

[0082] In some embodiments, the gold precursor used in a vapor deposition process for depositing a gold-containing thin film may comprise an organometallic compound. In some embodiments, the gold precursor may comprise a sulfur-containing organometallic compound. In some embodiments, the gold precursor may comprise at least one sulfur-containing ligand, such as a sulfur donor ligand, and at least one alkyl ligand, such as at least one methyl or ethyl ligand. As used herein, the sulfur donor ligand is a ligand bonded via a sulfur atom. In some embodiments, the gold in the gold precursor may comprise a +III oxidation state. In some embodiments, the gold precursor may comprise at least one sulfur donor ligand and two independently selected alkyl ligands. In some embodiments, the gold precursor comprises at least one sulfur-containing bidentate ligand, such as a bidentate sulfur donor ligand. In some embodiments, the bidentate sulfur donor ligand comprises one sulfur atom, such as a donor sulfur atom bonded to gold, and another atom, such as a nitrogen, selenium, or oxygen atom bonded to gold. In some embodiments, the bidentate sulfur donor ligand makes the compound thermally stable. In some embodiments, the gold precursor comprises at least two sulfur-containing monodentate ligands, such as sulfur donor ligands. In some embodiments, the gold precursor comprises at least two sulfur-containing monodentate ligands, such as two sulfur donor ligands and an alkyl ligand.

[0083] In some embodiments, the gold precursor may comprise a selenium-containing organometallic compound. In some embodiments, the gold precursor may comprise at least one selenium-containing ligand, such as a selenium donor ligand, and at least one alkyl ligand, such as at least one methyl or ethyl ligand. As used herein, the selenium donor ligand is a ligand bonded via a selenium atom. In some embodiments, the gold in the gold precursor may comprise a +III oxidation state. In some embodiments, the gold precursor may comprise at least one selenium donor ligand and two independently selected alkyl ligands. In some embodiments, the gold precursor comprises at least one selenium-containing bidentate ligand, such as a bidentate selenium donor ligand. In some embodiments, the bidentate selenium donor ligand comprises one selenium atom or, in some embodiments, two selenium atoms. In some embodiments, the bidentate selenium donor ligand comprises a ν atom, such as a donor selenium atom bonded to gold, and another atom, such as a nitrogen, selenium, or oxygen atom bonded to gold. In some embodiments, the bidentate selenium donor ligand makes the compound thermally stable. In some embodiments, the gold precursor comprises at least two selenium-containing monodentate ligands, such as selenium donor ligands. In some implementations, the gold precursor comprises at least two selenium-containing monodentate ligands, such as two selenium donor ligands and an alkyl ligand.

[0084] In some embodiments, the gold precursor may comprise one or more additional neutral adducts. The adductor forming ligand may be an ether, polyether, thioether, polysulfide, amine, or polyamine or its derivatives, such as THF (tetrahydrofuran), DME (dimethyl ether), diethylene glycol dimethyl ether, dimethyl sulfide, 1,2-bis(methylthio)ethane, tetrahydrothiophene, TMEDA (tetramethylethylenediamine), diene, Et3N, pyridine, quinine ring, or 1-methylpyrrolidone or its derivatives.

[0085] In some embodiments, the gold precursor may comprise two independently selected alkyl ligands and a sulfur-containing ligand such as a sulfur donor ligand. In some embodiments, the sulfur-containing ligand may comprise a dithiocarbamate ligand. In some embodiments, the sulfur-containing ligand may comprise a thiocarbamate ligand. In some embodiments, the sulfur-containing ligand may comprise an alkylthiocarbamate ligand, for example, a dialkylthiocarbamate ligand. In some embodiments, the sulfur-containing ligand may comprise a dialkylthiocarbamate ligand, such as a diethylthiocarbamate ligand. In some embodiments, the sulfur-containing ligand may comprise a dialkyldithiocarbamate ligand, such as a diethyldithiocarbamate ligand. In some embodiments, the gold precursor may comprise the diethyldithiocarbamate of dimethyl gold(III) (Me2Au(S2CNEt2)). In some embodiments, the gold precursor may comprise a thioamide ligand, a β-thiodione ligand, a β-dithiodione ligand, a β-thioketone imine ligand, a thiocarboxylic acid ligand, and / or a dithiocarboxylic acid ligand.

[0086] In some embodiments, the gold precursor may comprise a sulfur-containing ligand, such as a sulfur donor ligand, and a bidentate ligand, for example, a ligand selected from one of 2,2,6,6-tetramethyl-3,5-heptadecanedione ligand (THD), hexafluoroacetylacetone ligand (HFAC), and 2,2-dimethyl-6,6,7,7,8,8,8-heptafluorooctane-3,5-dione ligand (FOD). In some embodiments, the gold precursor may comprise two independently selected alkyl ligands and a carboxylic acid ligand, a thiocarboxylic acid ligand, or a dithiocarboxylic acid ligand. In some embodiments, the gold precursor may comprise an alkyl ligand, such as two independently selected alkyl ligands and a ligand having the formula SR, wherein R is an independently selected alkyl group. In some embodiments, the gold precursor may also comprise a ligand having the formula OR, wherein R is an independently selected alkyl group.

[0087] In some embodiments, the alkyl ligand of the gold precursor may contain fewer than 5, 4, 3, or 2 carbon atoms. In some embodiments, the alkyl ligand may contain one carbon atom, as in a methyl group. In some embodiments, the alkyl ligand may contain two carbon atoms, as in an ethyl group. In some embodiments, the alkyl ligand is not a substituted alkyl ligand.

[0088] Second reactant

[0089] In some embodiments, the second reactant may comprise oxygen. In some embodiments, the second reactant may comprise reactive species of oxygen, such as oxygen atoms, oxygen radicals, oxygen ions, and / or oxygen plasma. In some embodiments, the second reactant may comprise ozone (O3). In some embodiments, the second reactant may comprise molecular oxygen (O2) and ozone. In some embodiments, the second reactant may not contain any oxygen-containing compounds other than ozone. In some embodiments, the second reactant may comprise nitrogen, such as N2O. In some embodiments, the second reactant may comprise a peroxide, such as H2O2.

[0090] In some embodiments, the second reactant may not contain H2O. In some embodiments, the second reactant does not contain plasma, such as oxygen plasma. However, in some other embodiments, the second reactant may contain reactive species generated from plasma containing oxygen gas.

[0091] In some embodiments, the second precursor contains ozone and less than about 50%, 25%, 15%, 10%, 5%, 1% or 0.1% of impurities other than inert gases.

[0092] Film properties

[0093] The gold-containing thin film deposited according to some embodiments described herein can be a continuous gold-containing thin film. In some embodiments, the gold-containing thin film deposited according to some embodiments described herein can be continuous at a thickness of less than about 100 nm, less than about 60 nm, less than about 50 nm, less than about 40 nm, less than about 30 nm, less than about 25 nm, or less than about 20 nm, or less than about 15 nm, or less than about 10 nm, or less than about 5 nm, or even less. The mentioned continuity can be physical continuity or electrical continuity. In some embodiments, the thickness that makes the film physically continuous may be different from the thickness that makes the film electrically continuous, and the thickness that makes the film electrically continuous may be different from the thickness that makes the film physically continuous.

[0094] While in some embodiments the gold-containing thin films deposited according to some embodiments described herein may be continuous, in other embodiments it may be desirable to form discontinuous gold-containing thin films, or films comprising individual islands or nanoparticles containing gold. In some embodiments, the deposited gold-containing thin films may comprise gold-containing nanoparticles that are substantially not physically or electrically continuous with each other. In some embodiments, the deposited gold-containing thin films may comprise individual nanoparticles or individual islands containing gold.

[0095] In some embodiments, gold-containing films deposited according to embodiments described herein may have a resistivity of less than about 20 µΩcm at a thickness of less than about 100 nm. In some embodiments, gold-containing films deposited according to embodiments described herein may have a resistivity of less than about 20 µΩcm at a thickness of less than about 60 nm, less than about 50 nm, less than about 40 nm, less than about 30 nm, less than about 25 nm, or less than about 20 nm or less. In some embodiments, gold-containing films deposited according to embodiments described herein may have a resistivity of less than about 15 µΩcm at a thickness of less than about 60 nm, less than about 50 nm, less than about 40 nm, less than about 30 nm, less than about 25 nm, or less than about 20 nm or less. In some embodiments, gold-containing thin films deposited according to some embodiments described herein may have a resistivity of less than about 10 µΩcm at a thickness of less than about 60 nm, less than about 50 nm, less than about 40 nm, less than about 30 nm, less than about 25 nm, or less than about 20 nm or less. In some embodiments, gold-containing thin films deposited according to some embodiments described herein may have a resistivity of less than about 200 µΩcm at a thickness of less than about 30 nm, less than about 20 nm, less than about 15 nm, less than about 10 nm, less than about 8 nm, or less than about 5 nm or less.

[0096] In some embodiments, gold-containing films deposited according to some embodiments described herein may have resistivities of less than about 200 µΩcm, less than about 100 µΩcm, less than about 50 µΩcm, less than about 30 µΩcm, less than about 20 µΩcm, less than about 18 µΩcm, less than about 15 µΩcm, less than about 12 µΩcm, less than about 10 µΩcm, less than about 8 µΩcm, or less than about 5 µΩcm or less at a thickness of less than about 100 nm. In some embodiments, gold-containing films deposited according to some embodiments described herein may have resistivities of less than about 20 µΩcm, less than about 18 µΩcm, less than about 15 µΩcm, less than about 12 µΩcm, less than about 10 µΩcm, less than about 8 µΩcm, or less than about 5 µΩcm or less at a thickness of less than about 50 nm.

[0097] In some embodiments, the gold-containing thin film deposited according to some embodiments described herein may be crystalline or polycrystalline. In some embodiments, the gold-containing thin film deposited according to some embodiments described herein may have a cubic crystal structure.

[0098] In some embodiments, the gold-containing thin film deposited according to some embodiments described herein may have a thickness of about 20 nm to about 100 nm. In some embodiments, the gold-containing thin film deposited according to some embodiments described herein may have a thickness of about 20 nm to about 60 nm. In some embodiments, the gold-containing thin film deposited according to some embodiments described herein may have a thickness greater than about 20, greater than about 30 nm, greater than about 40 nm, greater than about 50 nm, greater than about 60 nm, greater than about 100 nm, greater than about 250 nm, greater than about 500 nm, or greater. In some embodiments, the gold-containing thin film deposited according to some embodiments described herein may have a thickness less than about 50 nm, less than about 30 nm, less than about 20 nm, less than about 15 nm, less than about 10 nm, less than about 5 nm, or in some cases, the amount of gold corresponds to a thickness less than about 5 nm, less than about 3 nm, less than about 2 nm, or less than about 1 nm, for example, if a discontinuous film or individual particles or islands containing gold are desired.

[0099] In some embodiments, the membrane growth rate is from about 0.01 Å / cycle to about 5 Å / cycle, or from about 0.05 Å / cycle to about 2 Å / cycle. In some embodiments, the membrane growth rate is greater than about 0.1 Å / cycle, greater than about 0.3 Å / cycle, greater than about 0.5 Å / cycle, greater than about 0.7 Å / cycle, greater than about 0.8 Å / cycle, greater than about 0.9 Å / cycle, greater than about 1 Å / cycle, greater than about 1.1 Å / cycle, or greater than about 1.2 Å / cycle or greater.

[0100] In some embodiments, the gold-containing film may contain less than about 20 atomic%, less than about 10 atomic%, less than about 7 atomic%, less than about 5 atomic%, less than about 3 atomic%, less than about 2 atomic%, or less than about 1 atomic% of impurities, i.e., elements other than Au. In some embodiments, the gold-containing film may contain less than about 20 atomic%, less than about 10 atomic%, less than about 5 atomic%, less than about 2 atomic%, or less than about 1 atomic% of hydrogen. In some embodiments, the gold-containing film may contain less than about 10 atomic%, less than about 5 atomic%, less than about 2 atomic%, less than about 1 atomic%, or less than about 0.5 atomic% of carbon. In some embodiments, the gold-containing film may contain less than about 5 atomic%, less than about 2 atomic%, less than about 1 atomic%, less than about 0.5 atomic%, or less than about 0.2 atomic% of nitrogen. In some embodiments, the gold-containing film may contain less than about 15 atomic%, less than about 10 atomic%, less than about 5 atomic%, less than about 3 atomic%, less than about 2 atomic%, or less than about 1 atomic% of oxygen. In some embodiments, the gold-containing film may contain less than about 5 atomic%, less than about 1 atomic%, less than about 0.5 atomic%, less than about 0.2 atomic%, or less than about 0.1 atomic% of sulfur. In some embodiments, the gold-containing film may contain more than about 80 atomic%, more than about 90 atomic%, more than about 93 atomic%, more than about 95 atomic%, more than about 97 atomic%, or more than about 99 atomic% of gold.

[0101] In some embodiments, a gold-containing thin film may be deposited on a three-dimensional structure. In some embodiments, in structures with an aspect ratio (height / width) greater than about 2, greater than about 5, greater than about 10, greater than about 25, or greater than about 50, the step coverage of the gold-containing thin film may be equal to or greater than about 50%, greater than about 80%, greater than about 90%, about 95%, about 98%, or about 99%, or higher.

[0102] Example

[0103] Example 1

[0104] The thermal properties of diethyldithiocarbamate of dimethyl gold(III) (Me2Au(S2CNEt2)) were investigated. Me2Au(S2CNEt2) was found to be solid at room temperature. Upon heating, it was observed to melt between approximately 40 °C and approximately 44 °C. As shown in Figure 3, the thermogravimetric analysis (TGA) curves for Me2Au(S2CNEt2) (heating rate 10 °C / min, 10 mg sample size, N2 flow at 1 atm) indicate almost complete evaporation below approximately 220 °C.

[0105] Example 2

[0106] Gold-containing thin films were deposited according to some embodiments and the ALD-type method described herein. Me₂Au(S₂CNEt₂) was used as the gold precursor and ozone (O₃) was used as the second reactant. Gold-containing sample thin films were deposited at temperatures of 120°C, 150°C, 180°C, and 200°C. Each thin film sample was deposited according to some embodiments and the deposition method described herein, comprising 500 deposition cycles, each cycle having a 1-second gold precursor pulse time, a 1-second gold precursor purge time, a 1-second ozone pulse time, and a 1-second ozone purge time.

[0107] As shown in Figure 4A, the growth rate, measured in Å / cycle, increases with increasing film deposition temperature, from approximately 0.4 Å / cycle at 120 °C to approximately 1.1 Å / cycle at 200 °C.

[0108] The sample films were found to be homogeneous, as shown in Figure 4B. The thickness of each gold-containing sample film remained substantially uniform across the entire substrate from the precursor inlet adjacent to the reaction space to a distance of 4.0 cm from the precursor inlet. Unlike previous chemical reaction-based vapor deposition methods such as ALD or CVD, this uniformity was achieved for gold-containing films at very low film thicknesses (approximately 20 nm to approximately 60 nm).

[0109] The resistivity of the sample films was measured, and it was found that all the deposited sample films were conductive, such as... Figure 4C As shown in the figure, the resistivity decreased from about 50 µΩcm at a deposition temperature of 120 °C to about 5 µΩcm at a deposition temperature of 150 °C, and remained below about 10 µΩcm for films deposited at 180 °C and 200 °C. These results indicate that, unlike previous gold vapor deposition methods, the deposited gold-containing sample films are continuous and conductive.

[0110] The crystal structure of the deposited sample film was determined by X-ray diffraction. As shown in Figure 4D, the intensity peaks of the X-ray diffraction pattern indicate that the sample film has a cubic crystal structure at all deposition temperatures, suggesting the deposition of metallic gold.

[0111] The sample films were also studied using scanning electron microscopy, as shown in Figures 5A-D. The SEM images show that, unlike previous gold vapor deposition methods, the gold-containing sample films exhibit uniform and continuous thicknesses of approximately 20 nm to approximately 60 nm across all deposition temperatures between 120 °C and 200 °C. At all deposition temperatures between 120 °C and 200 °C, the deposited gold-containing sample films completely covered the substrate.

[0112] Example 3

[0113] Gold-containing films were deposited according to several embodiments and the ALD-type method described herein. Me₂Au(S₂CNEt₂) was used as the gold precursor, and ozone (O₃) was used as the second reactant. The deposition temperature for all sample films was 180 °C. Each film sample was deposited according to several embodiments and the deposition method described herein, consisting of 500 deposition cycles. The pulse times for the gold precursor and second reactant varied between 0.5 sec and 2 sec, while the purge time remained constant at 1 sec.

[0114] like Figure 6A As shown, the growth rate, measured in Å / cycle, saturates at a precursor pulse length of 1 second. This growth rate was found to be approximately 0.9 Å / cycle. For the range of precursor pulse lengths studied, the growth rate varied between approximately 0.8 Å / cycle and approximately 0.9 Å / cycle.

[0115] As shown in Figure 6B, the gold-containing sample film deposited with a 1-second precursor pulse time was found to be more uniform than the sample film deposited with a 2-second precursor pulse time. In both cases, the sample films were found to be uniform and continuous at a very low thickness of approximately 43 nm to approximately 45 nm.

[0116] The resistivity of the sample films was measured, and it was found that all the deposited sample films were conductive, such as... Figure 6C As shown in the figure, the resistivity decreased from approximately 17 µΩcm for the deposition method with a precursor pulse time of 0.5 seconds to approximately 5 µΩcm for the deposition method with a precursor deposition time of 2 seconds. It was found that as the precursor pulse time increased from 1 second to 1.5 seconds, the resistivity increased slightly from approximately 10 µΩcm to approximately 12 µΩcm. These results indicate that the deposited gold-containing sample film is continuous and conductive.

[0117] Example 4

[0118] Gold-containing films were deposited according to some embodiments and the ALD-type method described herein. Me₂Au(S₂CNEt₂) was used as the gold precursor, and ozone (O₃) was used as the second reactant. Sample films were deposited at a temperature of 180°C. The number of deposition cycles varied for each sample film, ranging from 50 to 500 cycles. Each deposition cycle consisted of a 1-second gold precursor pulse time, a 1-second gold precursor purge time, a 1-second ozone pulse time, and a 1-second ozone purge time.

[0119] like Figure 7A As shown, the sample film thickness increased approximately linearly from less than about 5 nm in a deposition method involving 50 deposition cycles to about 45 nm in a deposition method involving 500 deposition cycles.

[0120] The sample films were also studied using scanning electron microscopy, as shown in Figures 7B-D. (SEM images)

[0121] The results show that the sample film deposited through 500 cycles is uniform and continuous.

[0122] Example 5

[0123] Gold-containing sample films were deposited according to some embodiments and the ALD-type method described herein. Me₂Au(S₂CNEt₂) was used as the gold precursor and ozone (O₃) was used as the second reactant. The first sample was prepared at a deposition temperature of 120 °C, while the second sample was prepared at a deposition temperature of 180 °C. Both film samples were deposited according to some embodiments and the deposition method described herein, comprising 500 deposition cycles, each cycle having a 10-second gold precursor pulse time, a 10-second gold precursor purge time, a 10-second ozone pulse time, and a 10-second ozone purge time.

[0124] The first gold-containing film, deposited at 120°C, was found to be approximately 21 nm thick. The second gold-containing film, deposited at 180°C, was found to be approximately 47 nm thick. The composition of the films was analyzed and is shown in Table 1 below. Sulfur was not detected in either sample film.

[0125]

[0126] Table 1: Film composition of two gold-containing sample films deposited at 120℃ and 180℃

[0127] The degree language used in this document, such as the terms "approximately," "about," "generally," and "basically," indicates a value, quantity, or characteristic that is close to the stated value, quantity, or characteristic and still performs the desired function or achieves the desired result. For example, the terms "approximately," "about," "generally," and "basically" may refer to a quantity that is less than or equal to 10% of the stated quantity, less than or equal to 5% of the stated quantity, less than or equal to 1% of the stated quantity, less than or equal to 0.1% of the stated quantity, and less than or equal to 0.01% of the stated quantity. If the stated quantity is 0 (e.g., none), then the ranges listed above may be specific ranges and not within a specific percentage of that value. For example, within 10% by weight / volume of the stated amount, within 5% by weight / volume of the stated amount, within 1% by weight / volume of the stated amount, within 0.1% by weight / volume of the stated amount, and within 0.01% by weight / volume of the stated amount.

[0128] For simplicity, the terms “membrane” and “thin film” are used herein. “Membrane” and “thin film” refer to any continuous or discontinuous structure and material deposited by the methods disclosed herein. For example, “membrane” and “thin film” can include 2D materials, nanorods, nanotubes, or nanoparticles, or even single partial or complete molecular layers, or partial or complete atomic layers, or atomic and / or molecular clusters. “Membrane” and “thin film” may contain materials or layers with pores, but are still at least partially continuous.

[0129] Those skilled in the art will understand that a wide variety of modifications can be made without departing from the spirit of the invention. The described features, structures, characteristics, and precursors can be combined in any suitable manner. Therefore, it should be clearly understood that the form of the invention is illustrative only and is not intended to limit the scope of the invention. It is intended that all modifications and variations fall within the scope of the invention as defined in the appended claims.

Claims

1. A method for forming a gold-containing thin film on a substrate in a reaction space, the method comprising: Expose the substrate to the pretreatment reactants; The substrate is contacted alternately and sequentially with the vapor-phase gold precursor and the vapor-phase second reactant; The formed film is annealed in an atmosphere containing hydrogen gas. The fumed gold precursor contains at least one ligand comprising sulfur or selenium and at least one alkyl ligand; The second reactant contains oxygen; The gold precursor and the second reactant react to form the gold-containing thin film, and The method described therein has a deposition temperature of about 120°C to about 200°C.

2. The method of claim 1, wherein alternating and sequentially contacting the substrate with the vapor-phase gold precursor and the vapor-phase second reactant comprises repeating two or more deposition cycles.

3. The method of claim 2, wherein the deposition cycle further includes removing excess fumed gold precursor and reaction byproducts from the reaction space, if any, after contacting the substrate with the fumed gold precursor.

4. The method of claim 2, wherein the deposition cycle further comprises removing excess second reactant and reaction byproducts from the reaction space, if any, after contacting the substrate with the second reactant.

5. The method of claim 1, wherein the gold of the gold precursor has a +III oxidation state.

6. The method of claim 1, wherein the ligand comprising sulfur or selenium comprises sulfur.

7. The method of claim 1, wherein the ligand comprising sulfur or selenium comprises selenium.

8. The method of claim 1, wherein the gold precursor comprises one or more additional neutral adducts.

9. The method of claim 1, wherein the gold precursor comprises a diethyldithiocarbamate ligand.

10. The method of claim 9, wherein the gold precursor comprises Me2Au(S2CNEt2).

11. The method of claim 1, wherein the second reactant comprises a reactive species of oxygen.

12. The method of claim 11, wherein the second reactant comprises ozone.

13. The method of claim 2, wherein the gold-containing film is continuous when it reaches a thickness of about 20 nm.

14. The method of claim 13, wherein the gold-containing film has a thickness of about 20 nm to about 50 nm.

15. The method of claim 13, wherein the gold-containing thin film has a resistivity of less than about 20 µΩcm.

16. The method of claim 2, wherein the gold-containing film has a growth rate greater than about 0.8 Å per deposition cycle.

17. The method according to claim 2, wherein the method is atomic layer deposition (ALD).

18. The method according to claim 2, wherein the method is a cyclic chemical vapor deposition (CVD) method.

19. An atomic layer deposition (ALD) method for forming a gold-containing thin film on a substrate in a reaction space, wherein the ALD method comprises multiple deposition cycles, wherein at least one deposition cycle comprises: The substrate is contacted alternately and sequentially with the vapor-phase gold precursor and the vapor-phase second reactant; The formed film is annealed in an atmosphere containing hydrogen gas. The deposition cycle is repeated two or more times to form the gold-containing film. The gold in the fumed gold precursor has a +III oxidation state and the fumed gold precursor comprises at least one sulfur donor ligand and at least one alkyl ligand. The second reactant contains oxygen. The method described therein has a deposition temperature of approximately 120°C to approximately 200°C, and In this process, the substrate is exposed to pretreatment reactants before it comes into contact with the vapor phase gold precursor.

20. The method of claim 19, wherein the gold precursor comprises Me2Au(S2CNEt2).

21. The method of claim 19, wherein the second reactant comprises ozone.

22. The method of claim 19, wherein the gold-containing film is continuous when it reaches a thickness of about 0 nm.

23. The method of claim 19, wherein the gold-containing film is continuous after 100 deposition cycles.

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