Homoleptic bismuth precursors for the deposition of bismuth oxide-containing thin films

Abstract

The disclosed and claimed subject matter relates to (i) homoleptic precursors of formula Bi(Ar), where Ar is one or more bulky alkyl groups selected from iso-propyl, sec-butyl, iso-butyl, neo-pentyl, sec-pentyl, and iso-pentyl, and (ii) their use as precursors for the deposition of metal-containing films.

Description

[Technical field]

[0001] The disclosed and claimed subject matter comprises: (i) a compound of formula Bi(Ar): 3 wherein Ar is a bulky alkyl group selected from iso-propyl, sec-butyl, iso-butyl, neo-pentyl, sec-pentyl, and iso-pentyl, and (ii) their use as precursors for the deposition of metal-containing films. [Background technology]

[0002] Metal-containing films are used in semiconductor and electronics applications. Chemical vapor deposition (CVD) and atomic layer deposition (ALD) have been applied as the primary deposition techniques to produce thin films for semiconductor devices. These methods allow the achievement of conformal films (metals, metal oxides, metal nitrides, metal silicides, and the like) through chemical reactions of metal-containing compounds (precursors). The chemical reactions occur on surfaces that may include metals, metal oxides, metal nitrides, metal silicides, and other surfaces. In CVD and ALD, the precursor molecules play a critical role in achieving high quality films with high conformality and low impurities. The temperature of the substrate in CVD and ALD processes is an important consideration in selecting the precursor molecules. Higher substrate temperatures, in the range of 150-500 degrees Celsius (°C), promote higher film growth rates. The preferred precursor molecules should be stable in this temperature range. The preferred precursors are capable of being delivered to the reaction vessel in liquid phase. Liquid phase delivery of precursors generally provides a more uniform delivery of precursors to the reaction vessel than solid phase precursors.

[0003] CVD and ALD processes are increasingly being used because they offer the advantages of enhanced compositional control, high film uniformity, and effective control of doping, and further provide excellent conformal step coverage over the highly non-planar geometries associated with modern microelectronic devices.

[0004] CVD is a chemical process that uses precursors to form thin films on a substrate surface. In a typical CVD process, precursors are passed over the surface of a substrate (e.g., a wafer) in a low-pressure or atmospheric pressure reaction chamber. The precursors react and / or decompose on the substrate surface to produce a thin film of deposited material. Plasma can be used to assist the precursor reaction or to improve material properties. Volatile by-products are removed by gases flowing through the reaction chamber. The deposited film thickness can be difficult to control because it depends on the adjustment of many parameters, such as temperature, pressure, gas flow and uniformity, chemical depletion effects, and time.

[0005] ALD is a chemical method for the deposition of thin films. ALD is a unique self-limiting, continuous film growth technique based on surface reactions that provides precise thickness control and allows conformal thin films of precursor-provided materials to be deposited on surface substrates of various compositions. In ALD, precursors are separated during reaction. A first precursor is passed over the substrate surface, producing a monolayer on the substrate surface. Excess unreacted precursor is pumped out of the reaction chamber. A second precursor or co-reactant is then passed over the substrate surface, reacting with the first precursor and forming a second monolayer on the first formed monolayer on the substrate surface. Plasma may be used to assist the reaction of precursors or co-reactants or to improve material quality. The cycle is repeated to produce a film of the desired thickness.

[0006] Thin films, especially metal-containing thin films, have a variety of important applications, such as in nanotechnology and the manufacture of semiconductor devices. Examples of such applications include capacitor electrodes, gate electrodes, adhesive diffusion barriers, and integrated circuits.

[0007] Trimethylbismuth (BiMe 3 ) and triphenylbismuth (BiPh 3) are volatile homoleptic bismuth compounds that are somewhat useful as ALD precursors. Nevertheless, they are not practical options for ALD applications. In particular, trimethylbismuth is difficult to purify and deliver in a safe manner. See Adv. Mater. Opt. Electron., 10, 193 (2000); Integr. Ferroelectr., 45, 215 (2002). Trimethylbismuth is also a pyrophoric liquid and is stabilized with dioxane to prevent explosions when used as a bismuth source in MOCVD applications. Trimethylbismuth and triethylbismuth have been used for MOCVD applications, but are not practical options for atomic layer deposition due to their very low thermal stability. See Chem. Vap. Deposition, 19, 61-67 (2013). Triphenylbismuth has good thermal stability and has been used for atomic layer deposition, but triphenylbismuth is a solid with a very low vapor pressure. See Thin Solid Films, 622, 65-70 (2017) and Chem. Vap. Deposition, 6, 139-145 (2000). These shortcomings make them problematic for high volume manufacturing of semiconductor devices and therefore preclude their use in applications requiring conformality and a high degree of control over precursor flux.

[0008] Virtual Bi(Np) 3 For the complex, the cone angle has been theoretically calculated, see Koordinatsyonnaya Khimiya, 11(9), 1171-1178 (1985). This reference does not report the synthesis or characterization of this material.

[0009] Apart from the homoleptic alkyl and aryl compounds for consideration as bismuth precursors, other bismuth compounds are known for use in ALD in limited capacity, such as: [ka] See Coord.Chem.Rev.,251,974-1006(2007); Coord.Chem.Rev.,257,3297-3322(2013); Organomet.Chem.,42,1-53(2019). For example, bismuth tris(2,2,6,6-tetramethyl-3,5-heptanedionate) has a high molecular weight and requires high source temperatures for precursor delivery. This precursor has a narrow ALD window of 275-300 °C. At lower deposition temperatures, precursor condensation was observed, but at higher temperatures, the growth rate per cycle decreased. See J.Phys.Chem.C,116,3449-3456(2012).

[0010] Bismuth alkoxide compounds are relatively easy to prepare and are volatile. Bismuth alkoxide precursors were used to prepare Bismuth alkoxide films on a substrate heated to 200°C or less. 2 O 3 However, at temperatures above 200°C, specifically close to 300°C, the thermal decomposition rate is fast, so the bismuth alkoxide is 2 O 3 is unlikely to be suitable for ALD of 1,000,000 uranium. See J. Vac. Sci. Technol. A., 32(1), 01A113 (2014).

[0011] Silicon-containing bismuth compounds are problematic in ozone-ALD processes. The precursors tris(hexamethyldisilazane)bismuth and tris(trimethylsilylmethyl)bismuth have been shown to deposit bismuth silicate thin films in ozone-based ALD. See Chem. Vap. Deposition, 11, 362-367 (2005).

[0012] The use of bismuth compounds is also described in Thin Solid Films, 622, 65-70 (2017); U.S. Patent Nos. 5,902,639; 7,618,681; 6,916,944; 10,186,570; and U.S. Patent Application Publication No. 2010 / 0279011. Any of these references or the above references may be incorporated herein by reference in their entirety to the BiNp disclosed and claimed herein. 3 Through the process of using 2 O 3 does not describe a viable ALD. Summary of the Invention

[0013] The disclosed and claimed subject matter comprises: (i) a compound of formula Bi(Ar): 3 The present invention relates to homoleptic precursors of the formula (I) wherein Ar is a bulky alkyl group selected from isopropyl, sec-butyl, iso-butyl, neo-pentyl, sec-pentyl and iso-pentyl, and (ii) their use as precursors for deposition of bismuth oxide thin films under high throughput process parameters. Moreover, the process parameters are compatible with current state-of-the-art methods for depositing high quality metal oxide thin films in semiconductor manufacturing. Thus, mixed metal oxide thin films are achievable with the methods and compositions of the present invention. When two or more processes are compatible, both processes can be run consecutively on a single instrument without requiring downtime to switch between parameters (e.g., changing substrate temperature). High throughput process parameters for atomic layer deposition target short cycle times. The precursor compositions of the present invention allow for high precursor fluxes, short precursor purge times, self-limiting growth behavior at substrate temperatures of about 200° C. to about 400° C., and the use of ozone as a second precursor in some embodiments.

[0014] In one preferred embodiment, the formula Bi(Ar) 3 The homoleptic precursor of is tri(neo-pentyl)bismuth (BiNp 3 "). [ka]

[0015] In one preferred embodiment, the formula Bi(Ar) 3 The homoleptic precursor of is tri(sec-pentyl)bismuth.

[0016] In one preferred embodiment, the formula Bi(Ar) 3 The homoleptic precursor of is tri(iso-pentyl)bismuth.

[0017] In one embodiment, the formula Bi(Ar) 3 The homoleptic precursor of is tri(iso-propyl)bismuth.

[0018] In one embodiment, the formula Bi(Ar) 3 The homoleptic precursor of is tri(sec-butyl)bismuth.

[0019] In one embodiment, the formula Bi(Ar) 3 The homoleptic precursor of is tri(iso-butyl)bismuth.

[0020] In another embodiment, the disclosed and claimed subject matter includes the use of the above-described heteroleptic bismuth compounds in an ALD deposition process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] All references cited in this specification, including publications, patent applications, and patents, are herein incorporated by reference to the same extent as if each reference was individually and specifically indicated to be incorporated by reference and was set forth in its entirety herein.

[0022] The use of the terms "a," "an," "the," and similar referents in the context of describing the disclosed and claimed subject matter (particularly in the context of the claims below) are to be construed to encompass both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms "comprising," "having," "including," and "containing" are to be construed as open-ended terms (i.e., meaning "including, but not limited to"), unless otherwise indicated. The recitation of ranges of values ​​herein is intended merely to serve as a shorthand method for individually referring to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order, unless otherwise indicated herein or clearly contradicted by context. The use of any and all examples or exemplary language (e.g., "such as") provided herein is intended merely to better describe the disclosed and claimed subject matter and does not pose a limitation on the scope of the disclosed and claimed subject matter unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the disclosed and claimed subject matter. In this specification and in the claims, use of the terms "comprising" or "including" includes the narrower language "consisting essentially of" and "consisting of."

[0023] Embodiments of the disclosed and claimed subject matter are described herein, including the best mode known to the inventors for carrying out the disclosed and claimed subject matter. Variations of these embodiments may become apparent to those of skill in the art upon reading the foregoing description. The inventors expect those of skill in the art to make appropriate use of such variations, and the inventors intend for the disclosed and claimed subject matter to be practiced other than as specifically described herein. Accordingly, the disclosed and claimed subject matter includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the disclosed and claimed subject matter unless otherwise indicated herein or clearly contradicted by context.

[0024] For ease of reference, "microelectronic device" or "semiconductor device" corresponds to semiconductor wafers having integrated circuits, memories, and other electronic structures fabricated thereon, as well as flat panel displays, phase change memory devices, solar panels, and other products including solar substrates, photovoltaics, and microelectromechanical systems (MEMS) fabricated for use in microelectronic, integrated circuit, or computer chip applications. Solar substrates include, but are not limited to, silicon, amorphous silicon, polycrystalline silicon, single crystal silicon, CdTe, copper indium selenide, copper indium sulfide, and gallium arsenide on gallium. Solar substrates may be doped or undoped. It is understood that the terms "microelectronic device" or "semiconductor device" are not meant to be limiting in any way and include any substrate that will ultimately become a microelectronic device or microelectronic assembly.

[0025] As defined herein, the term "barrier material" corresponds to any material used in the art to encapsulate metal wiring, e.g., copper interconnects, to minimize diffusion of the metal, e.g., copper, into dielectric materials. Preferred barrier layer materials include tantalum, titanium, ruthenium, hafnium, and other refractory metals and their nitrides and silicides.

[0026] "Substantially free" is defined herein as less than 0.001% by weight. "Substantially free" also includes 0.000% by weight. The term "free" means 0.000% by weight. As used herein, "about" or "approximately" is intended to correspond to within ±5% of the stated value. The term "substantially free" also refers to, for example, chloride (i.e., chloride-containing species such as HCl or bismuth compounds having at least one Bi-Cl bond) as well as compounds of the formula Bi(Ar) 3 The term "substantially free" may refer to halide ions (or halides), such as fluoride, bromide and iodide, as impurities in bismuth compounds having the formula Bi(Ar) . The level of halide impurities is less than 5 ppm (by weight) as measured by ion chromatography (IC), preferably less than 3 ppm as measured by IC, more preferably less than 1 ppm as measured by IC, and most preferably 0 ppm as measured by IC. In addition, the term "substantially free" refers to the presence of a bismuth compound having the formula Bi(Ar) 3 Metal ions, such as Li, may be present as impurities in bismuth compounds having the formula + , Na + , K + ,Mg 2+ , Ca 2+ , Al 3+ , Fe 2+ , Fe 3+ , Ni 2+ and Cr 3+As used herein, the term "substantially free" refers to Li, Na, K, Mg, Ca, Al, Fe, Ni, and Cr, each of which is less than 5 ppm (by weight), preferably less than 3 ppm, more preferably less than 1 ppm, and most preferably 0.1 ppm, as measured by ICP-MS or other analytical method for measuring the metal.

[0027] In all such compositions where certain components of a composition are discussed with reference to a weight percentage (or "wt %") range including a zero lower limit, it is understood that such components may or may not be present in various specific embodiments of the composition, and that when such components are present, they may be present in concentrations as low as 0.001 wt %, based on the total weight of the composition in which such components are used. Note that all percentages of components are weight percentages and are based on the total weight of the composition, i.e., 100%. Any reference to "one or more" or "at least one" includes "two or more" and "three or more", etc.

[0028] Where applicable, unless otherwise indicated, all weight percentages are "neat," meaning that they do not include the aqueous solution they are in when added to the composition. For example, "neat" refers to the weight percent amount of undiluted acid or other material (i.e., a content of 100 g of 85% phosphoric acid constitutes 85 g of acid and 15 grams of diluent).

[0029] Furthermore, when referring to compositions described herein in terms of weight percent, the weight percent of all components, including non-essential components such as impurities, is not to be understood to add up to more than 100% by weight in any case. In a composition "consisting essentially of" a recited component, such components can be added up to 100% by weight of the composition, or can be added up to less than 100% by weight. In the case of components added up to less than 100% by weight, such compositions may contain small amounts of non-essential contaminants or impurities. For example, in one such embodiment, the formulation can contain 2% or less by weight of impurities. In another embodiment, the formulation can contain 1% or less by weight of impurities. In a further embodiment, the formulation can contain 0.05% or less by weight of impurities. In other such embodiments, the components can form at least 90% by weight of the composition, more preferably at least 95% by weight, more preferably at least 99% by weight, more preferably at least 99.5% by weight, and most preferably at least 99.9% by weight, and can include other components that do not substantially affect the performance of the composition. Otherwise, it is understood that in the absence of significant non-essential impurity ingredients, the composition of all essential components adds up to essentially 100% by weight.

[0030] The headings used herein are not intended to be limiting; rather, they are included for organizational purposes only.

[0031] Disclosed and claimed bismuth precursors.

[0032] In one embodiment, the disclosed and claimed subject matter has the formula Bi(Ar) 3 where Ar is a neo-pentyl group, a sec-pentyl group, and an iso-pentyl group.

[0033] In one preferred embodiment, the formula Bi(Ar) 3 The homoleptic precursor of is tri(neo-pentyl)bismuth (BiNp 3 "). [ka]

[0034] In one embodiment, the disclosed and claimed subject matter comprises tri(neo-pentyl)bismuth ("BiNp 3 ").

[0035] In one preferred embodiment, the formula Bi(Ar) 3 The homoleptic precursor of is tri(sec-pentyl)bismuth.

[0036] In one embodiment, the disclosed and claimed subject matter includes a formulation comprising, consisting essentially of, or consisting of tri(sec-pentyl)bismuth.

[0037] In one preferred embodiment, the formula Bi(Ar) 3 The homoleptic precursor of is tri(iso-pentyl)bismuth.

[0038] In one embodiment, the disclosed and claimed subject matter includes a formulation comprising, consisting essentially of, or consisting of tri(iso-pentyl)bismuth.

[0039] How to use.

[0040] The disclosed and claimed subject matter further comprises a compound of formula Bi(Ar): 3 wherein Ar is a bulky alkyl group selected from iso-propyl, sec-butyl, iso-butyl, neo-pentyl, sec-pentyl, and iso-pentyl, depositing the bismuth-containing film using any chemical vapor deposition process known to one of skill in the art. As used herein, the term "chemical vapor deposition process" refers to any process in which a substrate is exposed to one or more volatile precursors that react and / or decompose on the substrate surface to produce the desired deposit.

[0041] In one embodiment, the method includes the use of one or more of the homoleptic bismuth precursors described above to deposit a bismuth-containing film using an atomic layer deposition process (ALD). As used herein, the term "atomic layer deposition process" or ALD refers to a continuous surface chemistry that deposits a film of material on a substrate of various compositions that is self-limiting (e.g., the amount of film material deposited in each reaction cycle is constant). Although the precursors, reagents and sources used herein are sometimes described as "gases", it is understood that the precursors can be either liquids or solids that are transported to the reactor via direct vaporization, bubbling or sublimation, with or without an inert gas. In some cases, the vaporized precursors can be passed through a plasma generator. As used herein, the term "reactor" includes, but is not limited to, a reaction chamber, a reaction vessel or a deposition chamber.

[0042] Chemical vapor deposition processes that can utilize the homoleptic bismuth precursor include, but are not limited to, those used in the manufacture of semiconductor-type microelectronic devices and the like, such as ALD and plasma-enhanced ALD (PEALD). In one embodiment, for example, a metal-containing film is deposited using an ALD process. In another embodiment, for example, a metal-containing film is deposited using a plasma-enhanced ALD (PEALD) process.

[0043] Suitable substrates onto which the homoleptic bismuth precursor can be deposited are not particularly limited and will vary depending on the intended end use. For example, the substrate may be HfO 2 based materials, TiO 2 based material, ZrO 2 The substrate may be selected from oxide or nitride based films such as nitride based materials, rare earth oxide based materials, ternary oxide based materials, etc. Other substrates include metal substrates (e.g., Au, Pd, Rh, Ru, W, Al, Ni, Ti, Co, Pt, and metal silicides (e.g., TiSi 2 , CoSi 2 , and NiSi 2); metal nitride-containing substrates (e.g., TaN, TiN, WN, TaCN, TiCN, TaSiN, and TiSiN); semiconductor materials (e.g., Si, SiGe, GaAs, InP, diamond, GaN, and SiC); insulators (e.g., SiO 2 , Si 3 N 4 , SiON, HfO 2 , Ta 2 O 5 , ZrO 2 , TiO 2 , Al 2 O 3 The substrate may include a solid substrate such as HfO, HfO 2 , HfO 3 , HfO 4 , HfO 5 , HfO 6 , HfO 7 , HfO 8 , HfO 9 , HfO 10 , HfO 11 , HfO 12 , HfO 13 , HfO 14 , HfO 15 , HfO 16 , Hf 2 based materials, TiO 2 based material, ZrO 2 These include oxide-based materials, rare earth oxide-based materials, and silicon oxide-based substrates.

[0044] In such deposition methods and processes, an oxidizing agent may be utilized. The oxidizing agent is typically introduced in gaseous form. Examples of suitable oxidizing agents include, but are not limited to, oxygen gas, water vapor, ozone, oxygen plasma, or mixtures thereof.

[0045] The deposition methods and processes may also include one or more purge gases. Purge gases used to purge unconsumed reactants and / or reaction by-products are inert gases that do not react with the precursors. Exemplary purge gases are argon (Ar), nitrogen (N), and argon (Ar). 2 A purge gas, such as, for example, Ar, including but not limited to, argon (Ar), helium (He), neon, and mixtures thereof, is fed into the reactor at a flow rate ranging from about 10 to about 2000 sccm for about 0.1 to 10000 seconds, thereby purging unreacted materials and any by-products that may remain in the reactor.

[0046] The deposition methods and processes require the application of energy to the homoleptic bismuth precursor, oxidizer, other precursors, or combinations thereof to induce a reaction and form a metal-containing film or coating on the substrate. Such energy can be provided by, but is not limited to, thermal, plasma, pulsed plasma, helicon plasma, high density plasma, inductively coupled plasma, x-ray, e-beam, photon, remote plasma methods, and combinations thereof. In some processes, a secondary RF frequency source can be used to modify the plasma characteristics at the substrate surface. When utilizing plasma, the plasma generation process can include a direct plasma generation process in which the plasma is generated directly in the reactor, or alternatively, a remote plasma generation process in which the plasma is generated outside of the reactor and fed into the reactor.

[0047] When utilized in such deposition methods and processes, the homoleptic bismuth precursor can be delivered to a reaction chamber, such as an ALD reactor, in a variety of ways. In some cases, a liquid delivery system can be utilized. In other instances, a combination liquid delivery and flash evaporation process unit, such as a turbo evaporator manufactured by MSP Corporation of Shoreview, Minn., can be used to allow for volumetric delivery of low volatility materials, resulting in reproducible transport and deposition without thermal decomposition of the precursor. BiNp 3 can be effectively used as source reagents via direct liquid injection (DLI) to provide vapor flows of these metal precursors to an ALD reactor.

[0048] When used in these deposition methods and processes, the homoleptic bismuth precursor formulations can be mixed with and include hydrocarbon solvents, which are particularly desirable due to their ability to be dried to sub-ppm levels for water. Exemplary hydrocarbon solvents that can be used for the precursor include, but are not limited to, toluene, mesitylene, cumene (isopropylbenzene), p-cymene (4-isopropyltoluene), 1,3-diisopropylbenzene, octane, dodecane, 1,2,4-trimethylcyclohexane, n-butylcyclohexane, and decahydronaphthalene (decalin). The disclosed and claimed precursors can also be stored and used in stainless steel containers. In certain embodiments, the hydrocarbon solvent is a high boiling solvent or has a boiling point of 100 degrees Celsius or greater. The disclosed and claimed precursors can also be mixed with other suitable metal precursors, and the mixture used to simultaneously deliver both metals for the growth of bimetallic-containing films.

[0049] A flow of argon and / or other gases can be used as a carrier gas to help deliver the vapor containing the homoleptic bismuth precursor to the reaction chamber during precursor pulsing. When delivering the homoleptic bismuth precursor, the reaction chamber process pressure is 1-50 Torr, preferably 5-20 Torr.

[0050] Substrate temperature can be an important process variable in the deposition of high quality metal-containing films. Typical substrate temperatures range from about 150° C. to about 550° C. Higher temperatures can promote higher film growth rates.

[0051] In view of the above, one of ordinary skill in the art will recognize that the disclosed and claimed subject matter further includes the use of the above homoleptic bismuth precursors in chemical vapor deposition processes as follows:

[0052] In one embodiment, the disclosed and claimed subject matter includes a method for forming a bismuth-containing film on at least one surface of a substrate, the method comprising the steps of: a. providing a substrate having at least one surface within a reaction vessel; b. forming a bismuth-containing film on at least one surface by a thermal chemical vapor deposition (CVD) or atomic layer deposition (ALD) process using one of the homoleptic bismuth precursors described above as a metal source compound for the deposition process. In a further aspect of this embodiment, the method includes introducing at least one reactant into the reaction vessel, wherein the at least one reactant is selected from the group consisting of water, diatomic oxygen, oxygen plasma, ozone, NO, N 2 O, NO 2 , carbon monoxide, carbon dioxide, and combinations thereof. In another aspect of this embodiment, the method includes introducing at least one reactant to a reaction vessel, wherein the at least one reactant is selected from the group of ammonia, hydrazine, monoalkylhydrazine, dialkylhydrazine, nitrogen, nitrogen / hydrogen, ammonia plasma, nitrogen plasma, nitrogen / hydrogen plasma, and combinations thereof. In another aspect of this embodiment, the method includes introducing at least one reactant to a reaction vessel, wherein the at least one reactant is selected from the group of hydrogen, hydrogen plasma, a mixture of hydrogen and helium, a mixture of hydrogen and argon, hydrogen / helium plasma, hydrogen / argon plasma, a boron-containing compound, a silicon-containing compound, and combinations thereof.

[0053] In one embodiment, the disclosed and claimed subject matter includes a method of forming a bismuth-containing film via a cyclic chemical vapor deposition (CCVD) process at a temperature greater than 300° C., comprising the steps of: a. providing a substrate within a reaction vessel; b. introducing one of the homoleptic bismuth precursors and a feed gas into a reaction vessel; c. purging the reaction vessel with a purge gas; d. sequentially repeating steps b through c until a bismuth-containing film of desired thickness is obtained. In a further aspect of this embodiment, the source gas is water, diatomic oxygen, oxygen plasma, ozone, NO, N 2 O, NO 2 , carbon monoxide, carbon dioxide, and combinations thereof. In another aspect of this embodiment, the source gas is one or more of the nitrogen-containing source gases selected from ammonia, hydrazine, monoalkylhydrazine, dialkylhydrazine, nitrogen, nitrogen / hydrogen, ammonia plasma, nitrogen plasma, nitrogen / hydrogen plasma, and mixtures thereof. In a further aspect of this embodiment, the purge gas is selected from argon, nitrogen, helium, neon, and combinations thereof. In a further aspect of this embodiment, the method further comprises applying energy to the homoleptic bismuth precursor, the source gas, the substrate, and combinations thereof, the energy being one or more of thermal, plasma, pulsed plasma, helicon plasma, high density plasma, inductively coupled plasma, x-ray, e-beam, photon, remote plasma techniques, and combinations thereof. In a further aspect of this embodiment, step b of the method further comprises introducing the homoleptic bismuth precursor into the reaction vessel using a flow of carrier gas to deliver vapor of the precursor to the reaction vessel. In a further aspect of this embodiment, step b of the process further comprises the use of a solvent medium comprising one or more of toluene, mesitylene, isopropylbenzene, 4-isopropyltoluene, 1,3-diisopropylbenzene, octane, dodecane, 1,2,4-trimethylcyclohexane, n-butylcyclohexane, and decahydronaphthalene, and combinations thereof.

[0054] In one embodiment, the disclosed and claimed subject matter includes a method of forming a bismuth-containing film via a thermal atomic layer deposition (ALD) process or a thermal ALD-like process comprising the steps of: a. providing a substrate within a reaction vessel; b. introducing one of the homoleptic bismuth precursors described above into a reaction vessel; c. purging the reaction vessel with a first purge gas; d. introducing a feed gas into the reaction vessel; e. purging the reaction vessel with a second purge gas; f. sequentially repeating steps b through e until a bismuth-containing film of desired thickness is obtained. In a further aspect of this embodiment, the feed gas is water, dioxygen, ozone, NO, N 2 O, NO 2 , carbon monoxide, carbon dioxide, and combinations thereof. In another aspect of this embodiment, the source gas is one or more of the nitrogen-containing source gases selected from ammonia, hydrazine, monoalkylhydrazine, dialkylhydrazine, nitrogen, nitrogen / hydrogen, ammonia plasma, nitrogen plasma, nitrogen / hydrogen plasma, and mixtures thereof. In a further aspect of this embodiment, the first and second purge gases are each independently selected from one or more of argon, nitrogen, helium, neon, and combinations thereof. In a further aspect of this embodiment, the method further comprises applying energy to the one or more precursors, source gas, substrate, and combinations thereof, the energy being one or more of thermal, plasma, pulsed plasma, helicon plasma, high density plasma, inductively coupled plasma, x-ray, e-beam, photon, remote plasma, and combinations thereof. In a further aspect of this embodiment, step b of the method further comprises introducing the precursor into the reaction vessel using a flow of carrier gas to deliver a vapor of the precursor into the reaction vessel. In a further aspect of this embodiment, step b of the process further comprises the use of a solvent medium comprising one or more of toluene, mesitylene, isopropylbenzene, 4-isopropyltoluene, 1,3-diisopropylbenzene, octane, dodecane, 1,2,4-trimethylcyclohexane, n-butylcyclohexane, and decahydronaphthalene, and combinations thereof.

[0055] In one embodiment of the present disclosure, one of the homoleptic precursors described above may be used to codeposit a multicomponent oxide film, which may further include an oxide of one or more elements selected from magnesium, calcium, strontium, barium, aluminum, gallium, indium, titanium, zirconium, hafnium, vanadium, niobium, tantalum, molybdenum, tungsten, tellurium, and antimony.

[0056] In one embodiment, the disclosed and claimed subject matter includes a method of forming a bismuth-containing multi-component oxide film in a thermal atomic layer deposition (ALD) process or a thermal ALD-like process comprising the steps of: a. providing a substrate in a reactor; b. introducing one of the homoleptic bismuth precursors described above into a reaction vessel; c. introducing one or more co-precursors comprising an element other than bismuth into the reaction vessel; d. purging the reaction vessel with a first purge gas; e. introducing a feed gas into the reaction vessel; f. purging the reaction vessel with a second purge gas; g. sequentially repeating steps b through f until a bismuth-containing multi-component oxide film of desired thickness is obtained.

[0057] In another embodiment, the disclosed and claimed subject matter includes a method of forming a bismuth-containing multi-component oxide film in a thermal atomic layer deposition (ALD) process or a thermal ALD-like process comprising the steps of: a. providing a substrate in a reactor; b. introducing one of the homoleptic bismuth precursors described above into a reaction vessel; c. purging the reaction vessel with a first purge gas; d. introducing a feed gas into the reaction vessel; e. purging the reaction vessel with a second purge gas; f. introducing one or more co-precursors comprising an element other than bismuth into the reaction vessel; g. purging the reaction vessel with a third purge gas; h. introducing a feed gas into the reaction vessel; i. purging the reaction vessel with a fourth purge gas; j. sequentially repeating steps bi until a bismuth-containing multi-component oxide film of desired thickness is obtained.

[0058] Examples of co-precursors include, but are not limited to, trimethylaluminum, tetrakis(dimethylamino)titanium, tetrakis(ethylmethylamino)zirconium, tetrakis(ethylmethylamino)hafnium, and tris-isopropylcyclopentadienyllanthanum. EXAMPLES

[0059] Reference is now made to more specific embodiments of the present disclosure and experimental results which provide support for such embodiments. The examples are provided below to more fully illustrate the disclosed and claimed subject matter and should not be construed as in any way limiting the disclosed subject matter.

[0060] It will be apparent to those skilled in the art that various modifications and variations can be made in the disclosed subject matter and the specific examples provided herein without departing from the spirit or scope of the disclosed subject matter. Thus, the disclosed subject matter, including the description provided by the following examples, is intended to cover modifications and variations of the disclosed subject matter that fall within the scope of any claims and their equivalents.

[0061] Materials and Methods.

[0062] All reactions and manipulations described in the examples were carried out in an inert atmosphere glove box or under a nitrogen atmosphere using standard Schlenk techniques. All chemicals were received from Millipore-Sigma.

[0063] Tri(neo-pentyl)bismuth (Bi(Np) 3 ").

[0064] BiCl 3 (46.52 g, 116 mmol) was dissolved in 200 mL of THF and cooled to -78°C. neo-pentylMgCl (350 mL, 1 M in THF, 350 mmol) was added dropwise via cannula and the mixture was stirred for 18 h while warming to room temperature. All volatile components were removed under reduced pressure (1 Torr, 30°C) to give a light grey solid. The solid was extracted with portions of pentane (4 x 200 mL). Each portion of pentane was collected by filtration, combined, and then concentrated under reduced pressure (1 Torr) to give a white solid. The solid was sublimed to tri(neo-pentyl)bismuth (48 g, 96%) at 80°C and 100 mTorr.

[0065] analysis: 1 H NMR(C 6 D 6 ,25℃):1.09(s,27H),2.11(d,6H).

[0066] Bi(Np) 3 Chemical vapor deposition of bismuth-containing films using

[0067] To deposit bismuth-containing thin films, Bi(Np) 3 The deposition process was then tested using another homoleptic precursor, BiPh 3 The deposition process was compared with that using BiNp 3 BiPh 3 It is much more volatile than BiPh and required less heating of the vessel to generate sufficient vapor pressure. 3 The vessel temperature for Bi(Np) was set high at 160 °C to deliver an adequate amount of precursor vapor per pulse, while a vessel temperature of 85 °C was used to deliver an adequate amount of Bi(Np) vapor per pulse. 3 was sufficient to deliver an appropriate amount of precursor vapor.

[0068] "Bi CVD" experiments were performed using alternating pulses of precursor and carrier gas (Ar) only. No reactants were used in these experiments to demonstrate the feasibility of depositing bismuth-containing films by a thermal CVD process. As shown in Table 1, BiNp 3 deposited a bismuth-containing film of 1542 Å at 400 °C, whereas BiPh 3 deposited negligible amounts of bismuth at this temperature. These results clearly demonstrate the relationship between the number of bismuth-aryl bonds and thermal stability. Bi(Np) 3 is a preferred precursor for deposition of bismuth-containing films by thermal CVD above 320° C. due to its lower thermal stability, whereas below 280° C. it is sufficiently thermally stable to enable low-temperature ALD of bismuth-containing films, such as bismuth oxide.

[0069] [Table 1]

[0070] It is anticipated that the methods of the present invention may be used in conjunction with deposition tools commonly found in semiconductor manufacturing sites to produce bismuth-containing layers for logic applications and other potential functions.

[0071] The foregoing description is intended primarily for purposes of illustration. Although the disclosed and claimed subject matter has been shown and described with reference to exemplary embodiments thereof, it should be understood by those skilled in the art that the foregoing and various other changes, omissions, and additions in form and detail thereof may be made therein without departing from the spirit and scope of the disclosed and claimed subject matter.

Claims

1. Formula Bi(Ar) ３ A homoleptic precursor of the formula: where Ar is one of a neo-pentyl group, a sec-pentyl group, and an iso-pentyl group.

2. The formula Bi(Ar) ３ The homoleptic precursor of BiNp is tri(neo-pentyl)bismuth. ３ " ) is: 【Chemistry 1】 The precursor of claim 1.

3. The formula Bi(Ar) ３ 2. The precursor of claim 1, wherein the homoleptic precursor of is tri(sec-pentyl)bismuth.

4. The formula Bi(Ar) ３ 2. The precursor of claim 1, wherein the homoleptic precursor of is tri(iso-pentyl)bismuth.

5. A formulation comprising a precursor according to any one of claims 1 to 4.

6. 1. A method of forming a bismuth-containing film on at least one surface of a substrate, comprising: a. providing a substrate having at least one surface within a reaction vessel; b. Formula Bi(Ar) ３ forming a bismuth-containing film on the at least one surface by a chemical vapor deposition (CVD) or atomic layer deposition (ALD) process using a homoleptic precursor, where Ar is a bulky alkyl group selected from iso-propyl, sec-butyl, iso-butyl, neo-pentyl, sec-pentyl, and iso-pentyl; The method includes:

7. The formula Bi(Ar) ３ The method according to claim 6, wherein the homoleptic precursor of the formula (I) comprises a precursor according to any one of claims 1 to 4.

8. The method of claim 6 , wherein forming the bismuth-containing film comprises chemical vapor deposition (CVD).

9. The method of claim 6 , wherein forming the bismuth-containing film comprises thermal chemical vapor deposition (CVD).

10. The method of claim 6 , wherein forming the bismuth-containing film comprises cyclic chemical vapor deposition (CCVD).

11. The method of claim 6 , wherein forming the bismuth-containing film comprises atomic layer deposition (ALD).

12. 1. A method of forming a bismuth-containing film on at least one surface of a substrate, comprising: a. providing a substrate in a reaction vessel; b. Formula Bi(Ar) ３ introducing one or more precursors into the reaction vessel, including homoleptic precursors, where Ar is a bulky alkyl group selected from iso-propyl, sec-butyl, iso-butyl, neo-pentyl, sec-pentyl, and iso-pentyl; c. purging the reaction vessel with a first purge gas; d. introducing a feed gas into the reaction vessel; e. purging the reaction vessel with a second purge gas; f. sequentially repeating steps b through e until a desired thickness of said bismuth-containing film is obtained; The method includes:

13. The formula Bi(Ar) ３ The method according to claim 12, wherein the homoleptic precursor of comprises a precursor according to any one of claims 1 to 4.

14. The raw material gas is water, diatomic oxygen, oxygen plasma, ozone, NO, N ２ O, NO ２ 13. The method of claim 12, wherein the oxygen-containing feed gas is one or more selected from the group consisting of carbon monoxide, carbon dioxide, and combinations thereof.

15. 13. The method of claim 12, wherein the source gas is one or more nitrogen-containing source gases selected from ammonia, hydrazine, monoalkylhydrazine, dialkylhydrazine, nitrogen, nitrogen / hydrogen, ammonia plasma, nitrogen plasma, nitrogen / hydrogen plasma, and mixtures thereof.

16. 13. The method of claim 12, wherein the first and second purge gases are each independently selected from one or more of argon, nitrogen, helium, neon, and combinations thereof.

17. 13. The method of claim 12, further comprising applying energy to the one or more precursors, the feed gases, the substrate, and combinations thereof, the energy being one or more of thermal, plasma, pulsed plasma, helicon plasma, high density plasma, inductively coupled plasma, x-ray, e-beam, photon, remote plasma, and combinations thereof.

18. 13. The method of claim 12, wherein step b further comprises: introducing the one or more precursors into the reaction vessel using a flow of a carrier gas to deliver vapor of the one or more precursors to the reaction vessel.

19. 13. The method of claim 12, wherein step b further comprises using a solvent medium comprising one or more of toluene, mesitylene, isopropylbenzene, 4-isopropyltoluene, 1,3-diisopropylbenzene, octane, dodecane, 1,2,4-trimethylcyclohexane, n-butylcyclohexane, and decahydronaphthalene, and combinations thereof.

20. A precursor supply package comprising a container and a precursor according to any one of claims 1 to 4, said container adapted to contain and dispense said precursor.

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