Precursors for the deposition of bismuth-containing films

Abstract

The disclosed and claimed subject matter relates to bismuth precursors of formula Bi(Ra)x(Ar)3-x, where x=1 or 2, and their use as precursors for the deposition of metal-containing films.

Description

[Technical field]

[0001] The disclosed and claimed subject matter comprises a compound of formula Bi(R a ) x (Ar) 3-x wherein x=1 or 2, and their use as precursors for the deposition of bismuth-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, etc.) 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 the 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- 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 in nanotechnology and the manufacture of semiconductor devices, including capacitor electrodes, gate electrodes, adhesives, diffusion barriers, and integrated circuits.

[0007] Trimethylbismuth (BiMe3) and triphenylbismuth (BiPh3) are volatile homoleptic bismuth compounds that have some utility 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] Apart from the homoleptic alkyl and aryl compounds to consider as bismuth precursors, other bismuth compounds are known to be used for ALD with limited capacity as shown in Figure 1. 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).

[0009] Bismuth alkoxide compounds are relatively easy to prepare and are volatile. ALD of Bi2O3 has been demonstrated using bismuth alkoxide precursors on substrates heated below 200 °C. However, at higher temperatures above 200 °C, specifically approaching 300 °C, bismuth alkoxides are unlikely to be suitable for ALD of Bi2O3 due to the fast thermal decomposition rate. See J.Vac.Sci.Technol.A.,32(1),01A113(2014).

[0010] 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).

[0011] The use of bismuth compounds is also described in: Thin Solid Films, 622, 65-70 (2017); U.S. Pat. Nos. 5,902,639; 7,618,681; 6,916,944; 10,186,570; and U.S. Patent Application Publication No. 2010 / 0279011. None of these or the above references describe viable ALD of Bi2O3 via a process using a heteroleptic bismuth precursor with aryl and alkyl precursors as disclosed and claimed herein. Summary of the Invention

[0012] The disclosed and claimed subject matter comprises a compound of formula Bi(R a ) x (Ar) 3-x The present invention relates to bismuth precursors of the formula (I) where x=1 or 2, and their use as precursors for the 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 piece of equipment without requiring downtime to switch between parameters (e.g., changing the 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.

[0013] In one embodiment, the disclosed and claimed subject matter has the formula Bi(R a ) x (Ar) 3-x A heteroleptic bismuth compound of the formula: (i) x=1 or 2, (ii) Each R ais independently one of an unsubstituted linear C1-C6 alkyl group, a linear C1-C6 alkyl group substituted with one or more halogens, a linear C1-C6 alkyl group substituted with an amino group, an unsubstituted branched C3-C6 alkyl group, a branched C3-C6 alkyl group substituted with one or more halogens, a branched C3-C6 alkyl group substituted with an amino group, an unsubstituted amine, a substituted amine, and -Si(CH3)3; (iii) each Ar is independently one of a C3-C8 unsubstituted aromatic group, a C3-C8 aromatic group substituted with one or more halogens, a C3-C8 aromatic group substituted with an amino group, a five-membered heterocycle, and a six-membered heterocycle; Bismuth compounds of such formulas have been shown to have favorable thermal stability and vapor pressure for atomic layer deposition processes in the manufacture of semiconductor devices.

[0014] In one aspect of the above embodiment, each Ar is independently one of the following: [ka] Each R 1 ~R 12 are independently H or R a In a more particular embodiment, each R 1 -R 12 are independently H, an unsubstituted straight chain C1-C6 alkyl group, and an unsubstituted branched C3-C6 alkyl group.

[0015] In another embodiment, the disclosed and claimed subject matter includes the use of the above-described heteroleptic bismuth compounds in an ALD deposition process. [Brief description of the drawings]

[0016] The accompanying drawings, which are included to provide a further understanding of the disclosed subject matter and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosed subject matter and, together with the description, serve to explain the principles of the disclosed subject matter.

[0017] [Figure 1]FIG. 1 shows a prior art ALD bismuth precursor for depositing bismuth oxide-containing thin films; [Diagram 2] Figure 2 shows differential scanning calorimetry of BiMe3, BiPh2Me, and BiPh3, comparing the onset of thermal decomposition of each; [Diagram 3] FIG. 3 shows vapor pressure curves for heteroleptic bismuth precursors (including vapor pressure curves for the homoleptic precursors BiMe3 and BiPh3 for comparison); [Figure 4] FIG. 4 shows the growth rates of Bi2O3 thin films using heteroleptic and homoleptic bismuth precursors at various pulse times. The heteroleptic precursor showed better saturation behavior, indicative of an ALD mechanism; and [Diagram 5] FIG. 5 shows the dependence of bismuth oxide thickness on the number of ALD cycles, indicating that self-limiting growth can be achieved. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] 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.

[0019] 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."

[0020] 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 that such variations will be utilized by those of skill in the art as appropriate, and the inventors intend that the disclosed and claimed subject matter 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.

[0021] 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.

[0022] 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.

[0023] "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.

[0024] 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.

[0025] 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).

[0026] 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.

[0027] The headings used herein are not intended to be limiting; rather, they are included for organizational purposes only.

[0028] Exemplary embodiments

[0029] As noted above, the disclosed and claimed subject matter relates to heteroleptic bismuth compounds for use as ALD precursors.

[0030] Disclosed and claimed heteroleptic bismuth precursors

[0031] In one embodiment, the disclosed and claimed subject matter has the formula Bi(R a ) x (Ar) 3-xA heteroleptic bismuth compound of the formula: (i) x=1 or 2, (ii) Each R a is independently one of an unsubstituted linear C1-C6 alkyl group, a linear C1-C6 alkyl group substituted with one or more halogens, a linear C1-C6 alkyl group substituted with an amino group, an unsubstituted branched C3-C6 alkyl group, a branched C3-C6 alkyl group substituted with one or more halogens, a branched C3-C6 alkyl group substituted with an amino group, an unsubstituted amine, a substituted amine, and -Si(CH3)3; (iii) each Ar is independently one of a C3-C8 unsubstituted aromatic group, a C3-C8 aromatic group substituted with one or more halogens, a C3-C8 aromatic group substituted with an amino group, a five-membered heterocycle, and a six-membered heterocycle; and (iv) Precursors do not include: [ka] Bismuth compounds of such formulas have been shown to have favorable thermal stability and vapor pressure for atomic layer deposition processes in the manufacture of semiconductor devices.

[0032] R a Alkyl Substituents

[0033] As mentioned above, each R a is independently one of an unsubstituted linear C1-C6 alkyl group, a linear C1-C6 alkyl group substituted with one or more halogens, a linear C1-C6 alkyl group substituted with an amino group, an unsubstituted branched C3-C6 alkyl group, a branched C3-C6 alkyl group substituted with one or more halogens, a branched C3-C6 alkyl group substituted with an amino group, an unsubstituted amine, a substituted amine, and -Si(CH3)3.

[0034] In one embodiment, R a is an unsubstituted linear C1-C6 alkyl group. In one aspect of this embodiment, R a is a methyl group. In one aspect of this embodiment, R ais an ethyl group. In one aspect of this embodiment, R a is a propyl group. In one aspect of this embodiment, R a is a butyl group. In one aspect of this embodiment, R a is a pentyl group. In one aspect of this embodiment, R a is a hexyl group.

[0035] In one embodiment, R a is a substituted linear C1-C6 alkyl group substituted with one or more halogens. a is a methyl group substituted with one or more halogens. In one aspect of this embodiment, R a is an ethyl group substituted with one or more halogens. In one aspect of this embodiment, R a is a propyl group substituted with one or more halogens. In one aspect of this embodiment, R a is a butyl group substituted with one or more halogens. In one aspect of this embodiment, R a is a pentyl group substituted with one or more halogens. In one aspect of this embodiment, R a is a hexyl group substituted with one or more halogens. In one aspect of this embodiment, the one or more halogens include fluorine. In one aspect of this embodiment, the one or more halogens include chlorine. In one aspect of this embodiment, the one or more halogens include bromine. In one aspect of this embodiment, the one or more halogens include iodine.

[0036] In one embodiment, R a is a substituted linear C1-C6 alkyl group substituted with an amino group. a is a methyl group substituted with an amino group. In one aspect of this embodiment, R a is an ethyl group substituted with an amino group. a is a propyl group substituted with an amino group. In one aspect of this embodiment, R ais a butyl group substituted with an amino group. In one aspect of this embodiment, R a is a pentyl group substituted with an amino group. a is a hexyl group substituted with an amino group.

[0037] In one embodiment, R a is an unsubstituted branched C3-C6 alkyl group. In one aspect of this embodiment, R a is an isopropyl group. In one aspect of this embodiment, R a is an isobutyl group. In one aspect of this embodiment, R a is a sec-butyl group. In one aspect of this embodiment, R a is a tert-butyl group. In one aspect of this embodiment, R a is a branched pentyl group, e.g., neopentyl, sec-pentyl, or tert-pentyl. In one aspect of this embodiment, R a is a neopentyl group. In one aspect of this embodiment, R a is a branched hexyl group.

[0038] In one embodiment, R a is a substituted branched C3-C6 alkyl group substituted with one or more halogens. In one aspect of this embodiment, R a is an isopropyl group substituted with one or more halogens. In one aspect of this embodiment, R a is an isobutyl group substituted with one or more halogens. In one aspect of this embodiment, R a is a sec-butyl group substituted with one or more halogens. In one aspect of this embodiment, R a is a tert-butyl group substituted with one or more halogens. In one aspect of this embodiment, R a is a branched pentyl group substituted with one or more halogens. In one aspect of this embodiment, R a is a neopentyl group substituted with one or more halogens. In one aspect of this embodiment, R ais a branched hexyl group substituted with one or more halogens. In one aspect of this embodiment, the one or more halogens include fluorine. In one aspect of this embodiment, the one or more halogens include chlorine. In one aspect of this embodiment, the one or more halogens include bromine. In one aspect of this embodiment, the one or more halogens include iodine.

[0039] In one embodiment, R a is a substituted branched C3-C6 alkyl group substituted with an amino group. a is an isopropyl group substituted with an amino group. In one aspect of this embodiment, R a is an isobutyl group substituted with an amino group. In one aspect of this embodiment, R a is a sec-butyl group substituted with an amino group. a is a tert-butyl group substituted with an amino group. a is a branched pentyl group substituted with an amino group. In one aspect of this embodiment, R a is a neopentyl group substituted with an amino group. In one aspect of this embodiment, R a is a branched hexyl group substituted with an amino group.

[0040] In one embodiment, R a is an unsubstituted amine.

[0041] In one embodiment, R a is a substituted amine.

[0042] In one embodiment, R a is -Si(CH3)3.

[0043] In some embodiments, R a has the structure set out in Table 1: [Table 1]

[0044] R a The substituents are not limited to those exemplified in Table 1.

[0045] Ar substituent

[0046] As described above, each Ar is independently one of a C3-C8 unsubstituted aromatic group, a C3-C8 aromatic group substituted with one or more halogens, a C3-C8 aromatic group substituted with an amino group, a five-membered heterocycle, and a six-membered heterocycle.

[0047] In one embodiment, each Ar is independently one of the following: [ka] Each R 1 ~R 12 are independently H or R a In a more particular embodiment, each R 1 -R 12 is independently H. In a more particular embodiment, each R 1 -R 12 are independently a In a more particular embodiment, each R 1 -R 12 are independent and have the same R a In a more particular embodiment, each R 1 -R 12 is an unsubstituted linear C1-C6 alkyl group. In more particular embodiments, each R 1 -R 12 is an unsubstituted branched C3-C6 alkyl group.

[0048] In one embodiment, each Ar is: [ka] Each R 1 -R 5 are independently H or R a In a more particular embodiment, each R 1 -R 5is independently H. In a more particular embodiment, each R 1 -R 5 are independently a In a more particular embodiment, each R 1 -R 5 are independent and have the same R a In a more particular embodiment, each R 1 -R 5 is an unsubstituted linear C1-C6 alkyl group. In more particular embodiments, each R 1 -R 5 is an unsubstituted branched C3-C6 alkyl group.

[0049] In one embodiment, each Ar is: [ka] Each R 6 -R 9 are independently H or R a In a more particular embodiment, each R 6 -R 9 is independently H. In a more particular embodiment, each R 6 -R 9 are independently a In a more particular embodiment, each R 6 -R 9 are independent and have the same R a In a more particular embodiment, each R 6 -R 9 is an unsubstituted linear C1-C6 alkyl group. In more particular embodiments, each R 6 -R 9 is an unsubstituted branched C3-C6 alkyl group.

[0050] In one embodiment, each Ar is: [ka] Each R 10 -R 12 are independently H or R a In a more particular embodiment, each R10 -R 12 is independently H. In a more particular embodiment, each R 10 -R 12 are independently a In a more particular embodiment, each R 10 -R 12 are independent and have the same R a In a more particular embodiment, each R 10 -R 12 is an unsubstituted linear C1-C6 alkyl group. In more particular embodiments, each R 10 -R 12 is an unsubstituted branched C3-C6 alkyl group.

[0051] In some embodiments, Ar has the structure shown in Table 2: [Table 2]

[0052] Ar substituents are not limited to those exemplified in Table 2.

[0053] Exemplary Heteroleptic Bismuth Precursors

[0054] In one aspect of this embodiment, the heteroleptic bismuth compound is "BiPhNp2" having the following structure: [ka] In this embodiment, the formula Bi(R a ) x (Ar) 3-x In the formula, x=2, each Ra is a neopentyl group and each Ar is a phenyl group.

[0055] In one aspect of this embodiment, the heteroleptic bismuth compound is "BiPyr2Me" having the following structure: [ka] where x=1, Ra is a methyl group, and each Ar is [ka] It is.

[0056] In one aspect of this embodiment, the heteroleptic bismuth compound is "BiPyrNp2" having the following structure: [ka] where x=2, Ra is a neopentyl group, and Ar is [ka] It is.

[0057] In one aspect of this embodiment, the heteroleptic bismuth compound is "BiImid2Me" having the following structure or an isomer of the following structure: [ka] where x=1, Ra is a methyl group, and each Ar is [ka] It is.

[0058] In one aspect of this embodiment, the heteroleptic bismuth compound is "BiImidMe2" having one of the following structures or an isomer of the following structure: [ka]

[0059] How to use

[0060] The disclosed and claimed subject matter provides a method for depositing a bismuth-containing film using any chemical vapor deposition process known to one of skill in the art, comprising the steps of: a ) x (Ar) 3-xA heteroleptic bismuth compound of the formula: (i) x=1 or 2, (ii) Each R a is independently one of an unsubstituted linear C1-C6 alkyl group, a linear C1-C6 alkyl group substituted with one or more halogens, a linear C1-C6 alkyl group substituted with an amino group, an unsubstituted branched C3-C6 alkyl group, a branched C3-C6 alkyl group substituted with one or more halogens, a branched C3-C6 alkyl group substituted with an amino group, an unsubstituted amine, a substituted amine, and -Si(CH3)3; (iii) each Ar is independently one of a C3-C8 unsubstituted aromatic group, a C3-C8 aromatic group substituted with one or more halogens, a C3-C8 aromatic group substituted with an amino group, a five-membered heterocycle, and a six-membered heterocycle; 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 a desired deposit.

[0061] In one embodiment, the method includes the use of a heteroleptic bismuth compound 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.

[0062] In one embodiment, the heteroleptic bismuth compound used in the disclosed and claimed method for depositing a bismuth-containing film is the disclosed and claimed heteroleptic bismuth precursor Bi(R a ) x (Ar) 3-x In one aspect of this embodiment, the heteroleptic bismuth precursor comprises, consists essentially of, or consists of BiPhNp2. In one aspect of this embodiment, the heteroleptic bismuth precursor comprises, consists essentially of, or consists of BiPyr2Me. In one aspect of this embodiment, the heteroleptic bismuth precursor comprises, consists essentially of, or consists of BiPyrNp2. In one aspect of this embodiment, the heteroleptic bismuth precursor comprises, consists essentially of, or consists of BiImid2Me. In one aspect of this embodiment, the heteroleptic bismuth precursor comprises, consists essentially of, or consists of BiImidMe2.

[0063] In another embodiment, the heteroleptic bismuth compound used in the disclosed and claimed method for depositing a bismuth-containing film has the formula Bi(R a ) x (Ar) 3-x where x=1, R a is a methyl group and each Ar is a phenyl group ("BiPhMe"): [ka] The precursor BiPh2Me is described in Organometallics, 20(3), 586-589 (2001) and Chem. Ber., 118, 1031-1038 (1985), but has not been used in a deposition process.

[0064] In another embodiment, the heteroleptic bismuth compound used in the disclosed and claimed method for depositing a bismuth-containing film has the formula Bi(R a ) x (Ar) 3-x where x=2, each R a is a methyl group and Ar is a phenyl group ("BiPhMe2"): [ka] The precursor BiPhMe2 is described in Z. Naturforsch., B, 40, 1476 (1985) but has not been used in a deposition process.

[0065] In another embodiment, the heteroleptic bismuth compound used in the disclosed and claimed method for depositing a bismuth-containing film has the formula Bi(R a ) x (Ar) 3-x where x=1, Ra is a neopentyl group, and each Ar is a phenyl group ("BiPhNp"): [ka] The precursor BiPh2Np is described in Organometallics, 22(14), 2929-2924 (2003) but has not been used in a deposition process.

[0066] In another embodiment, the heteroleptic bismuth compound used in the disclosed and claimed method for depositing a bismuth-containing film can be represented by the formula Bi(R a ) x (Ar) 3-x The heteroleptic bismuth precursor may comprise, consist essentially of, or consist of:

[0067] Chemical vapor deposition processes in which the disclosed and claimed precursors can be utilized 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.

[0068] Suitable substrates on which the disclosed and claimed precursors can be deposited are not particularly limited and vary depending on the intended end use. For example, the substrate may be selected from oxide or nitride-based films, such as HfO2-based materials, TiO2-based materials, ZrO2-based materials, rare earth oxide-based materials, ternary oxide-based materials, etc. Other substrates can include solid substrates such as metal substrates (e.g., Au, Pd, Rh, Ru, W, Al, Ni, Ti, Co, Pt, and metal silicides (e.g., TiSi2, CoSi2, and NiSi2); 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., SiO2, Si3N4, SiON, HfO2, Ta2O5, ZrO2, TiO2, Al2O3, and barium strontium titanate); combinations thereof). Preferred substrates include HfO2-based materials, TiO2-based materials, ZrO2-based materials, rare earth oxide-based materials, and silicon oxide-based substrates.

[0069] 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.

[0070] The deposition methods and processes may also include one or more purge gases. The 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 include, but are not limited to, argon (Ar), nitrogen (N), helium (He), neon, and mixtures thereof. For example, a purge gas such as Ar 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.

[0071] Deposition methods and processes require the application of energy to at least one of the precursors, oxidizers, 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 the reactor and fed into the reactor.

[0072] When utilized in such deposition methods and processes, suitable precursors, such as those disclosed and claimed herein, 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 enable volumetric delivery of low volatility materials, resulting in reproducible transport and deposition without thermal decomposition of the precursor. The precursor compositions described herein can be effectively used as source reagents via direct liquid injection (DLI) to provide a vapor flow of these metal precursors to an ALD reactor.

[0073] When used in these deposition methods and processes, the disclosed and claimed precursors 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 precursors 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 point 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 metal-containing films.

[0074] A flow of argon and / or other gases can be used as a carrier gas to help deliver a vapor containing at least one of the disclosed and claimed precursors to the reaction chamber during precursor pulsing. When delivering the precursors, the reaction chamber process pressure is 1-50 Torr, preferably 5-20 Torr.

[0075] 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.

[0076] 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 disclosed and claimed precursors in chemical vapor deposition processes such as:

[0077] 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 atomic layer deposition (ALD) process using one of the disclosed and claimed precursors 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. In a further aspect of this embodiment, the method includes introducing at least one reactant into the reaction vessel, where the at least one reactant is selected from the group of water, dioxygen, oxygen plasma, ozone, NO, NO, NO, NO, carbon monoxide, carbon dioxide, and combinations thereof. In another aspect of this embodiment, the method includes introducing at least one reactant into the reaction vessel, where 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 into the reaction vessel, where 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.

[0078] 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 or more of the disclosed and claimed bismuth precursors 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 source gas is one or more oxygen-containing source gases selected from water, dioxygen, ozone, NO, NO, NO, NO, carbon monoxide, carbon dioxide, and combinations thereof. In another aspect of this embodiment, 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. 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 gases, 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 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 method 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.

[0079] In one aspect of the present disclosure, a bismuth precursor 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.

[0080] 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 or more of the disclosed and claimed bismuth precursors 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.

[0081] 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 or more of the disclosed and claimed bismuth precursors 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.

[0082] Examples of co-precursors include, but are not limited to, trimethylaluminum, tetrakis(dimethylamino)titanium, tetrakis(ethylmethylamino)zirconium, tetrakis(ethylmethylamino)hafnium, and tris-isopropylcyclopentadienyllanthanum.

[0083] In another embodiment, the bismuth-containing film is deposited directly on a substrate that promotes self-limiting growth, i.e., an "SLG oxide layer." The SLG oxide layer is a thin layer of oxide (also a thin film of oxide) that stimulates self-limiting growth of the bismuth-containing film. Self-limiting growth occurs where and when the deposition rate of the bismuth-containing film decreases substantially with increasing number of cycles. Self-limiting growth is desired for conformal deposition of thin films on high aspect ratio features. Without being bound by theory, it is believed that the self-limiting growth is due to the significantly lower deposition rate of the bismuth-containing film on the bismuth-containing film compared to the deposition rate of the bismuth-containing film on the SLG oxide layer.

[0084] Examples of SLG oxides may include, but are not limited to, aluminum oxide and titanium oxide. The thickness of the SLG oxide layer is preferably less than 5 nm, more preferably less than 3 nm, and even more preferably less than 1 nm. EXAMPLES

[0085] 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.

[0086] 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.

[0087] Materials and Methods

[0088] 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.

[0089] Specific Examples

[0090] Example 1: Synthesis of BiPh2Cl

[0091] BiCl3 (34.23 g) was dissolved in 100 mL of tetrahydrofuran. BiPh3 (28.35 g) was dissolved in 200 mL of tetrahydrofuran. The tetrahydrofuran solution of BiCl3 was added dropwise to the solution of BiPh3 at -10°C over 1.5 hours. The cloudy solution was stirred at room temperature overnight and filtered to remove a small amount of insoluble solid. The solvent was removed under reduced pressure to give a white solid. The solid was dried under reduced pressure at 60°C for 1 hour, washed with diethyl ether, and redried. 34.2 g of BiPh2Cl was recovered, 98%.

[0092] analysis: 1 H NMR(C6D6,25℃):7.35(m,4H), 7.62(t,4H), 8.29(d,2H)

[0093] Example 2: Synthesis and purification of BiPh2Me

[0094] The synthesis of BiPh2Me is described in Chem. Ber., 118, 1031-1038 (1985). Attempts to reproduce this procedure gave low purity material that was difficult to purify by vacuum distillation. Changing the reaction solvent to toluene gave pure material that could be purified by vacuum distillation. In theory, a heterogeneous reaction mixture in toluene would separate the product from insoluble impurities. The impurities, if soluble, would catalyze the decomposition of the product.

[0095] BiPh2Cl (34.23 g, 85.9 mmol) was suspended in 250 mL of toluene and cooled to -78 °C. MeLi (60 mL, 1.6 M in Et2O, 96 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 to give a cloudy oil. The oil was extracted with portions of hexane (3 x 50 mL). Each portion of hexane was collected by filtration. The filtrates were combined and concentrated under reduced pressure to give a colorless oil (30.42 g, 99%). The oil was purified by fractional distillation under reduced pressure. The first fraction gave a colorless oil (3.5 g, 1 The first major fraction was collected at 98 °C / 77 mTorr (25.2 g, 78%) as BiPhMe2 (confirmed as BiPhMe2 by H NMR).

[0096] analysis: 1 H NMR(C6D6,25℃):1.19(s,3H), 7.08-7.13(m,3H), 7.15-7.19(m,4H), 7.67-7.70(m,4H)

[0097] Example 3: Synthesis of BiPh(Np)

[0098] BiPhCl2 (37.63 g, 105.4 mmol) was suspended in 300 mL of toluene and cooled to -78 °C. NeopentylMgCl (209 mL, 1 M in THF, 209 mmol) was added dropwise via cannula and the mixture was stirred for 18 h while warming to room temperature. A large amount of solid had formed after 18 h such that magnetic stirring was ineffective. 200 mL of THF was added to dissolve the solid. Stirring was continued for 24 h. All volatile components were removed under reduced pressure to give a light brown solid. The solid was extracted with portions of hexane (3 x 150 mL). Each portion of hexane was collected by filtration. The three hexane filtrates were combined and concentrated under reduced pressure to give a colorless oil. The colorless oil was purified by vacuum distillation (41.22 g, 91.3%).

[0099] Analysis: 1H NMR (C6D6, 25℃): 1.02 (s, 18H), 2.15 (d, 2H), 2.27 (2, 2H), 7.13-7.17 (m, 1H), 7.19-7.24 (m, 2H), 7.81-7.84 (m, 2H)

[0100] Example 4: Synthesis of BiPyr(NP)2

[0101] Tris(N-methyl-2-pyrrolyl)bismuth (BiPyr3) was synthesized via salt metathesis of bismuth trichloride and N-methyl-2-pyrrolyllithium. Analytical data from Dalton Trans., 46, 8269-8278 (2017) were used for comparison to confirm the synthesis. BiPyr3 (3.04 g, 6.77 mmol) dissolved in 50 mL of THF was added dropwise to BiCl3 (4.27 g, 13.54 mmol) dissolved in 100 mL of THF. The solution was stirred for 18 h. NeopentylMgCl (40.6 mL, 1 M in THF, 40.6 mmol) was added dropwise via cannula while cooling to -78 °C. The mixture was stirred for 18 h while warming to room temperature. Volatiles were removed under reduced pressure of 1 torr and the flask was gently heated to 30 °C. The crude material was extracted with portions of hexane (3 x 50 mL). Each portion of hexane was collected by filtration. The filtrates were combined and concentrated under reduced pressure to give a cloudy oil (8.61 g, 98%). This oil was heated to 70°C at 60 mTorr and sublimed to trisneopentylbismuth. The oil was then heated to 110°C at 60 mTorr and a colorless liquid was distilled (2.17 g, 25%, bp = 63°C / 60 mTorr).

[0102] analysis: 1 H NMR(C6D6,25℃):1.01(s,18H), 2.20(d,2H), 2.49(2,2H), 3.23(s,3H), 6.52-6.55(m,2H), 6.65(t,1H)

[0103] Example 5: Synthesis of Bi(Np)

[0104] BiCl3 (46.52 g, 116 mmol) was dissolved in 200 mL of THF and cooled to -78 °C. NeopentylMgCl (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 gray 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 trisneopentylbismuth (48 g, 96%) at 80 °C and 100 mTorr.

[0105] analysis: 1 H NMR(C6D6,25℃):1.09(s,27H), 2.11(d,6H)

[0106] Example 6: Thermal analysis of heteroleptic bismuth precursors

[0107] Physical properties such as thermal stability and volatility are determined by the ligands in the precursor. Bismuth aryl compounds have low volatility and high thermal stability. Bismuth alkyl compounds have high volatility and low thermal stability. Heteroleptic bismuth precursors containing aryl and alkyl ligands surprisingly have intermediate physical properties with respect to homoleptic compounds. Atomic layer deposition using heteroleptic bismuth precursors can deposit thin films of Bi2O3 without the limitations imposed by low volatility and low thermal stability. Heteroleptic bismuth precursors enable atomic layer deposition of Bi2O3 in a manner suitable for mass production of semiconductor and memory devices.

[0108] Figure 2 shows the thermal stability analysis of BiMe3, BiPh2Me and BiPh3, measured by differential scanning calorimetry and comparing the respective onsets of thermal decomposition. The trend of thermal stability depended on the type of ligand in the compound. As shown in Table 3, BiMe3 started to decompose at about 170°C, BiPh2Me at about 250°C, and BiPh3 at around 300°C. Specifically, BiPh2Me and BiPh3 started to decompose at 250°C and 300°C, respectively.

[0109] [Table 3]

[0110] FIG. 3 shows the vapor pressure curves of the heteroleptic bismuth precursors (including the vapor pressure curves of the homoleptic precursors BiMe3 and BiPh3 for comparison).

[0111] Evaporation data for several heteroleptic bismuth compounds was collected by TGA to determine the temperature required to generate a vapor pressure of 1 Torr. As shown in Table 3, for BiPh2Me the temperature was determined to be 110°C. A range of 60-130°C was determined for all heteroleptic compounds. For comparison, a temperature of 175°C was determined for BiPh3. Regarding the vapor pressure data for BiMe3, Fluid Phase Equilibria, 360, 106-110 (2013) reports that the temperature required for a vapor pressure of 1 Torr is less than 20°C. This 1 Torr temperature is interesting for atomic layer deposition processes because it represents the set temperature of the precursor vessel to carry out the process in a rational manner. The precursors of the present invention have a vapor pressure of 1 torr from 30°C to 130°C.

[0112] Example 7: Deposition of bismuth-containing films

[0113] Several bismuth precursors were tested in deposition experiments to deposit Bi2O3 thin films. The experiments were carried out in a manner consistent with ALD (i.e., precursors and oxidant were delivered to the reaction chamber independently separated by an inert gas purge). In general, the heteroleptic bismuth precursors required reasonable vessel temperatures of about 100 °C to deliver a saturating pulse of gaseous precursor. This was expected due to their intermediate volatility characteristics compared to the homoleptic bismuth precursors. The tri(neopentyl)bismuth precursors are volatile and require mild vessel heating to generate sufficient vapor pressure. The vessel temperature for tri(phenyl)bismuth was set as high as 160 °C to deliver an adequate amount of precursor vapor per pulse. Heating the precursor vessel and delivery piping uniformly to about 100 °C without cold spots was a manageable task using heating jackets and heating tapes commonly used in ALD equipment.

[0114] "Bi CVD" experiments were performed to determine precursor stability under the reactor setup. Precursors were pulsed into the reaction chamber (without O3 oxidant) to measure the amount of bismuth deposited by thermal decomposition, as shown in Table 4. The heteroleptic precursors deposited less than 1 Å of bismuth after 100 pulses at 280 °C and 320 °C. At 400 °C, di(neopentyl)phenylbismuth deposited 3 Å of bismuth, indicating a slight increase in thermal decomposition. Tri(neopentyl)bismuth deposited 1542 Å of bismuth at 400 °C, while triphenylbismuth deposited negligible amounts of bismuth at all three temperatures. These results clearly demonstrate the relationship between the number of bismuth-aryl bonds and thermal stability. Furthermore, the heteroleptic bismuth precursors exhibited sufficient thermal stability to allow for the controlled deposition of Bi2O3 in a manner consistent with ALD. The growth rates of diphenylmethylbismuth and di(neopentyl)phenylbismuth were measured to be 0.13 Å / cycle with optimized precursor pulse times near saturation conditions. As shown in Figure 4, the precursor pulse times for diphenyl-methylbismuth and di(neopentyl)phenylbismuth were selected to be 5 s and 2 s for nearly self-limiting growth behavior according to the saturation curve. The conditions in Figure 4 are 280 °C, 100 cycles, 5 s O3 pulse for BiPh2Me; 2 s O3 pulse for BiPh(Np)2 and BiNp3. Notably, tri(neopentyl)bismuth did not show self-limiting growth, likely due to thermal decomposition of the precursor.

[0115] [Table 4]

[0116] Example 8: Self-limiting growth of Bi-containing films on SLG oxide layers

[0117] We demonstrated self-limiting growth (SLG) of bismuth-containing films on aluminum oxide SLG oxide layers. The experiments were performed in a manner consistent with ALD (i.e., precursor and oxidant were delivered into a reaction chamber independently separated by an inert gas purge). The SLG oxide layer was deposited by a trimethylaluminum / ozone thermal ALD process at 300°C. The bismuth oxide film was deposited using a BiPh2Me bismuth precursor at 280°C using the following ALD sequence: BiPh2Me / Ar purge / O3 / Ar purge = 5s / 43s / 2s / 43s. The number of cycles in the bismuth oxide ALD process was varied from 20 to 250 to determine whether self-limiting growth could be achieved. Figure 5 shows the dependence of bismuth oxide thickness on the number of ALD cycles. The results show that self-limiting growth can be achieved when aluminum oxide is used as the SLG oxide layer self-limiting growth of the bismuth oxide film, whereas self-limiting growth is not observed on zirconium oxide.

[0118] It is anticipated that the disclosed and claimed methods may be used in conjunction with deposition tools commonly found in semiconductor manufacturing sites to produce molybdenum-containing layers for logic applications and other potential functions.

[0119] 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(R ａ ) ｘ (Ar) ３－ｘ a precursor of (i) x=1 or 2; (ii) Each of the R ａ are independently unsubstituted linear C １ -C ６ Alkyl group, linear C substituted with one or more halogens １ -C ６ Linear C substituted with alkyl or amino groups １ -C ６ Alkyl group, unsubstituted branched C ３ -C ６ alkyl group, branched C substituted with one or more halogens ３ -C ６ Branched C substituted with alkyl group or amino group ３ -C ６ Alkyl groups, unsubstituted amines, substituted amines, and —Si(CH ３ ) ３ It is a type of (iii) each Ar is independently C ３ -C ８ an unsubstituted aromatic group of C substituted with one or more halogens; ３ -C ８ an aromatic group of C substituted with an amino group; ３ -C ８ is one of an aromatic group, a five-membered heterocycle, and a six-membered heterocycle; and (iv) the precursor does not include: 【Chemical 1】 Precursor.

2. The R ａ is an unsubstituted linear C １ -C ６ The precursor of claim 1 , comprising an alkyl group.

3. The R ａ is a substituted linear C １ -C ６ The precursor of claim 1 which is an alkyl group.

4. The R ａ is an unsubstituted branched C ３ -C ６ The precursor of claim 1 , comprising an alkyl group.

5. The R ａ is a substituted branched C substituted with an amino group ３ -C ６ The precursor of claim 1 , comprising an alkyl group.

6. The R ａ The precursor of claim 1 , wherein comprises an unsubstituted amine.

7. The R ａ The precursor of claim 1 , wherein comprises a substituted amine.

8. The R ａ comprises one or more of a methyl group, an ethyl group, a propyl group, an n-butyl group, an n-pentyl group, an isopropyl group, an isobutyl group, an isopentyl group, a sec-butyl group, a sec-pentyl group, a tert-butyl group, and a tert-pentyl group.

9. Each Ar independently comprises one of the following: 【Chemistry 2】 a precursor, wherein each R １ -R １２ is H or the R ａ and R ａ is as defined in claim 1.

10. Each Ar independently comprises one of the following: 【Table 1】 The precursor of claim 1 .

11. A precursor having the following structure: 【Chemistry 3】 2. The precursor of claim 1, wherein x=2, each Ra is a neopentyl group, and each Ar is a phenyl group.

12. A precursor having the following structure: 【Chemistry 4】 Here, x=1, the Ra is a methyl group, and each Ar is as follows: 【Chemistry 5】 The precursor of claim 1 .

13. A precursor having the following structure: 【Chemistry 6】 where x=1, each Ra is a methyl group, and each Ar is 【Chemistry 7】 The precursor of claim 1 .

14. A precursor having the following structure: 【Chemistry 8】 where x=2, each Ra is a methyl group, and each Ar is 【Chemistry 9】 The precursor of claim 1 .

15. A precursor having the following structure: 【Chemistry 10】 where x=2, each Ra is a methyl group, and each Ar is 【Chemistry 11】 The precursor of claim 1 .

16. A precursor having the following structure: 【Chemistry 12】 where x=2, each Ra is a methyl group, and each Ar is 【Chemistry 13】 The precursor of claim 1 .

17. A precursor having the following structure: 【Chemistry 14】 where x=2, each Ra is a neopentyl group, and Ar is 【Chemistry 15】 The precursor of claim 1 .

18. 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(R ａ ) ｘ (Ar) ３－ｘ one or more heteroleptic bismuth precursors of the formula: (i) x=1 or 2; (ii) Each of the R ａ are independently unsubstituted linear C １ -C ６ Alkyl group, linear C substituted with one or more halogens １ -C ６ Linear C substituted with alkyl or amino groups １ -C ６ Alkyl group, unsubstituted branched C ３ -C ６ alkyl group, branched C substituted with one or more halogens ３ -C ６ Branched C substituted with alkyl group or amino group ３ -C ６ Alkyl groups, unsubstituted amines, substituted amines, and —Si(CH ３ ) ３ It is a type of (iii) each Ar is independently C ３ -C ８ an unsubstituted aromatic group of C substituted with one or more halogens; ３ -C ８ an aromatic group of C substituted with an amino group; ３ -C ８ is one of an aromatic group, a five-membered heterocycle, and a six-membered heterocycle; forming a bismuth-containing film on the at least one surface by an atomic layer deposition (ALD) process using a precursor; A method comprising:

19. 19. The method of claim 18, wherein the heteroleptic bismuth precursor comprises one or more of BiPhNp2, BiPyr2Me, BiPyrNp2, BiImid2Me, and BiImidMe2.

20. The heteroleptic bismuth precursor has the formula Bi(R ａ ) ｘ (Ar) ３－ｘ wherein x=1, said R ａ is a methyl group, and each Ar is a phenyl group ("BiPh ２ Me"): 【Chemistry 16】 The method of claim 18 comprising a precursor.

21. The heteroleptic bismuth precursor has the formula Bi(R ａ ) ｘ (Ar) ３－ｘ wherein x=2, each R ａ is a methyl group, and Ar is a phenyl group ("BiPhMe ２ " ): 【Chemistry 17】 The method of claim 18 comprising a precursor.

22. The heteroleptic bismuth precursor has the formula Bi(R ａ ) ｘ (Ar) ３－ｘ wherein x=1, each Ra is a neopentyl group, and each Ar is a phenyl group ("BiPh ２ Np"): 【Chemistry 18】 The method of claim 18 comprising a precursor.

23. A method for manufacturing a substrate comprising: providing a substrate in a reaction vessel; b. Formula Bi(R ａ ) ｘ (Ar) ３－ｘ one or more heteroleptic bismuth precursors of the formula: (i) x=1 or 2; (ii) Each of the R ａ are independently unsubstituted linear C １ -C ６ Alkyl group, linear C substituted with one or more halogens １ -C ６ Linear C substituted with alkyl or amino groups １ -C ６ Alkyl group, unsubstituted branched C ３ -C ６ alkyl group, branched C substituted with one or more halogens ３ -C ６ Branched C substituted with alkyl group or amino group ３ -C ６ Alkyl groups, unsubstituted amines, substituted amines, and —Si(CH ３ ) ３ It is a type of (iii) each Ar is independently C ３ -C ８ an unsubstituted aromatic group of C substituted with one or more halogens; ３ -C ８ an aromatic group of C substituted with an amino group; ３ -C ８ is one of an aromatic group, a five-membered heterocycle, and a six-membered heterocycle; introducing a precursor into said reaction vessel; c) purging the reaction vessel with a first purge gas; d. introducing a source 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 the bismuth-containing film is obtained; 20. The method of claim 18, comprising:

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