Group II metal-containing film-forming composition and vapor deposition of a film using the same

Abstract

A method for forming a Group 2 metal-containing film on a substrate comprises: a) exposing the substrate to vapor of a Group 2 metal-containing film-forming composition containing an alkaline earth metal precursor having the following chemical formula: (wherein M is Be, Mg, Ca, Sr, or Ba; and R1 to R6 are each independently a C1-C10 alkyl group, a fluoro group, an alkylsilyl group, a germanyl group, an alkylamide, or an alkylsilylamide); b) forming a Group 2 metal-containing film by depositing at least a portion of the alkaline earth metal precursor on the substrate through a vapor deposition process; and c) repeating a) and b) until a Group 2 metal-containing film of a desired thickness is formed.

Description

Technology Field

[0001] Cross-reference regarding related applications

[0002] This application claims priority to U.S. Patent Application No. 18 / 409,331 filed January 10, 2024, the entire contents of which are incorporated herein by reference.

[0003] The present invention generally relates to a composition for forming a film containing a group 2 metal, and to depositing a film using the same, specifically to forming a film containing a group 2 metal using an alkaline earth metal precursor having the following chemical formula:

[0004]

[0005] (In the formula, M is Be, Mg, Ca, Sr, or Ba; R 1 to R 6 C1-C each independently 10 It is an alkyl group, a fluoro group, an alkylsilyl group, a germanyl group, an alkylamide, or an alkylsilylamide). Background Technology

[0006] As the design and manufacturing of semiconductor devices continue to evolve, the semiconductor industry is continuously seeking new and novel methods to deposit films on substrates so that the resulting films possess specific desired characteristics.

[0007] DRAM manufacturers have faced the challenge of maintaining adequate storage capacity per cell even as cell sizes shrink. To address this challenge, films utilizing alkaline earth metal oxides such as SrO, BaO, and CaO are currently being actively researched. These include perovskite (ABO3) materials such as SrTiO3 or BaSrTiO3 for ultra-high k materials, ruthenium-based materials such as CaRuO3, SrRuO3, and BaRuO3 for electrode applications, and SrO for doping into dielectrics. In the past, various strontium composites have been studied for the deposition of thin films by MOCVD (Metal Organic Chemical Vapor Deposition), ALD (Atomic Layer Deposition), or other vapor deposition methods. These composites include the following:

[0008] Sr(Me5Cp)2 has been used for the deposition of strontium films. This precursor is not volatile and is sometimes thermally unstable. The vaporization temperature of Sr(Me5Cp)2 is higher than 300°C. The vaporization of the precursor produces 20% residue due to decomposition.

[0009] WO2008 / 069821 by CAMERON et al. discloses amidinate and guanidinate. Sr2(iPr-iPr-iPr-GUA)4 is an example of this type of precursor. The main disadvantages of this precursor family are thermal instability and lack of volatility. Amidinate and guanidinate precursors are solids at room temperature and generally have high melting points. Additionally, they tend to form dimeric species.

[0010] β-diketonate ligands generally form solid, non-volatile complexes with Sr. Sr(thd)2 is a well-known member of the β-diketonate family. The melting point of this precursor is approximately 210°C, and its boiling point is higher than 350°C under atmospheric pressure. When SrO is deposited using Sr(thd)2 with O3, SrO is formed along with Sr2CO3. Deposition was not observed with Sr(thd)2 and water. This precursor is not suitable for deposition due to the difficulty of vaporization.

[0011] Sr(pivalate)2 is disclosed in the literature by ILJINA et al. [Materials science & engineering. B, Solid-state materials for advanced technology 1993, 18, 234-236]. This precursor is a solid and can sublimate from 370°C. The vapor pressure at this temperature is only 1.33 Pa. Sublimation produces nearly 60% residue. This precursor cannot be used for film deposition.

[0012] All known commercially available Group 2 metal-organic compounds are solids, and they are not desirable for application as CVD / ALD precursors in the current semiconductor industry. To the knowledge of the inventors, there are no suitable liquid strontium metal-organic compounds having the thermal behavior desired to enable vapor deposition of strontium-containing films.

[0013] Therefore, there is currently a need for the development of liquid precursors. means of solving the problem

[0014] A method for forming a Group 2 metal-containing film on a substrate is disclosed, and the method

[0015] a) a step of exposing a substrate to the vapor of a Group 2 metal-containing film-forming composition containing an alkaline earth metal precursor having the following chemical formula:

[0016]

[0017] (In the formula, M is Be, Mg, Ca, Sr, or Ba; R 1 to R 6 C1-C each independently 10 It is an alkyl group, a fluoro group, an alkylsilyl group, a germanyl group, an alkylamide, or an alkylsilylamide;

[0018] b) a step of forming a Group 2 metal-containing film by depositing at least a portion of an alkaline earth metal precursor onto a substrate through a vapor deposition process; and

[0019] c) a step of repeating a) and b) until a group 2 metal-containing film of the desired thickness is formed.

[0020] The disclosed deposition method may include one or more of the following features:

[0021] · The vapor deposition process is a metal-organic chemical vapor deposition (MOCVD) process;

[0022] · The vapor deposition process is an ALD process;

[0023] · The vapor deposition process is a thermal ALD, spatial ALD, temporal ALD, or plasma ALD process;

[0024] · The vapor deposition process is a thermal ALD process;

[0025] · The vapor deposition process is a spatial ALD process;

[0026] · The vapor deposition process is a temporal ALD process;

[0027] · The vapor deposition process is not a plasma ALD process;

[0028] · The vapor deposition process is a plasma ALD process;

[0029] The method further includes a step of exposing the surface to a co-reactant;

[0030] · The co-reactant is an oxidizing agent or a nitrating agent;

[0031] · The co-reactant is an oxidizing agent;

[0032] · The co-reactant is a nitrating agent;

[0033] The method further includes a step of separating each exposure step by purging the vapor of the excess Group II metal-containing film-forming composition and the excess co-reactant, respectively, using an inert gas such as N2, Ar, Kr, or Xe;

[0034] · Co-reactants are O3, O2, H2O, H2O2, D2O, ROH (where R is C1-C 10 It is a linear or branched hydrocarbon), selected from NH3, NO, N2O, hydrazine, amine, or a combination thereof;

[0035] · The co-reactant is H2O;

[0036] · The co-reactant is NH3;

[0037] · The inert gas is N2, Ar, Kr, or Xe;

[0038] · Alkaline earth metal precursors are mixed with a solvent;

[0039] · The solvent in the mixture is in the range of 0% to approximately 50%;

[0040] · The solvent is a substituted or unsubstituted hydrocarbon selected from alkanes, alkenes, and alkynes; an alcohol selected from alkyl alcohols and amino alcohols; or an amine selected from primary, secondary, and tertiary amines; tetrahydrofuran; dichloromethane; ethyl acetate; butyl acetate; acetonitrile; and dimethylformamide;

[0041] · Hydrocarbons include octane, ethylbenzene, xylene, mesitylene, decalin, decane, and dodecane;

[0042] · The concentration of alkaline earth metal precursors in the solvent varies;

[0043] · The metal-containing film-forming composition comprises an alkaline earth metal precursor in an amount of approximately 50% w / w to approximately 100.0% w / w;

[0044] · The concentration of alkaline earth metal precursors in the solvent is in the range of approximately 50% w / w to approximately 100.0% w / w;

[0045] · The substrate is exposed to the precursor at a temperature ranging from room temperature to approximately 500°C;

[0046] · The alkaline earth metal precursor is bis(tri-sec-butylcyclopentadienyl)strontium(II), Sr(sBu3Cp)2;

[0047] · The alkaline earth metal precursor is bis(tri-sec-butylcyclopentadienyl)barium(II), Ba(sBu3Cp)2;

[0048] · The alkaline earth metal precursor is bis(tri-iso-propylcyclopentadienyl)strontium(II), Sr(iPr3Cp)2;

[0049] · The alkaline earth metal precursor is bis(tri-tert-butylcyclopentadienyl)strontium(II), Sr(tBu3Cp)2;

[0050] · The alkaline earth metal precursor is bis(tri-iso-propylcyclopentadienyl)barium(II), Ba(iPr3Cp)2;

[0051] · The metal-containing film-forming composition contains impurities of approximately 0.0% w / w to approximately 5.0% w / w;

[0052] · Alkaline earth metal precursors are purified to a purity of approximately 95 wt% or in the range of 95% w / w to approximately 100 w / w;

[0053] · Alkaline earth metal precursors are purified to a purity in the range of approximately 99% w / w to approximately 99.999% w / w;

[0054] · Alkaline earth metal precursors are purified to a purity in the range of approximately 99% w / w to approximately 100% w / w;

[0055] · The group 2 metal-containing film is an SrO film; and

[0056] · The film containing Group 2 metals is a BaO film.

[0057] A method for depositing an SrO film on a substrate is disclosed, and the method

[0058] a) a step of exposing a substrate to vapor of bis(tri-sec-butylcyclopentadienyl)strontium(II), Sr(sBu3Cp)2;

[0059] b) a step of exposing the substrate to co-reactant H2O;

[0060] c) a step of forming an SrO film by depositing at least a portion of an alkaline earth metal precursor onto a substrate through a vapor deposition process; and

[0061] d) a) to c) repeating until an SrO film of the desired thickness is formed

[0062] The disclosed deposition method may include one or more of the following features:

[0063] · The vapor deposition process is the MOCVD process;

[0064] · The vapor deposition process is an ALD process;

[0065] · The vapor deposition process is a thermal ALD, spatial ALD, temporal ALD, or plasma ALD process;

[0066] · The vapor deposition process is a thermal ALD process;

[0067] · The vapor deposition process is a spatial ALD process;

[0068] · The vapor deposition process is a temporal ALD process;

[0069] · The vapor deposition process is not a plasma ALD process;

[0070] · The vapor deposition process is a plasma ALD process;

[0071] · Additionally includes a step of separating each exposure step by purging the vapor of the excess Group II metal-containing film-forming composition and the excess co-reactant, respectively, using an inert gas such as N2, Ar, Kr, or Xe;

[0072] · Sr(sBu3Cp)2 is mixed with the solvent;

[0073] · The solvent in the mixture is in the range of 0% to approximately 50%;

[0074] · The solvent is a substituted or unsubstituted hydrocarbon selected from alkanes, alkenes, and alkynes; an alcohol selected from alkyl alcohols and amino alcohols; or an amine selected from primary, secondary, and tertiary amines; tetrahydrofuran; dichloromethane; ethyl acetate; butyl acetate; acetonitrile; and dimethylformamide;

[0075] · Hydrocarbons include octane, ethylbenzene, xylene, mesitylene, decalin, decane, and dodecane;

[0076] · The concentration of Sr(sBu3Cp)2 in the solvent varies;

[0077] · The concentration of Sr(sBu3Cp)2 in the solvent is in the range of approximately 50% w / w to approximately 100.0% w / w;

[0078] · The substrate is exposed to the precursor at a temperature ranging from room temperature to approximately 500°C;

[0079] · Sr(sBu3Cp)2 contains impurities of approximately 0.0% w / w to approximately 5.0% w / w;

[0080] · Sr(sBu3Cp)2 is purified to a purity of approximately 95 wt% or in the range of 95% w / w to approximately 100% w / w;

[0081] · Sr(sBu3Cp)2 is purified to a purity in the range of approximately 99% w / w to approximately 99.999% w / w; and

[0082] · Sr(sBu3Cp)2 is purified to a purity in the range of approximately 99% w / w to approximately 100% w / w.

[0083] In addition, a method for depositing a BaO film on a substrate is disclosed, and this method

[0084] a) a step of exposing the substrate to vapor of bis(tri-sec-butylcyclopentadienyl)barium(II), Ba(sBu3Cp)2;

[0085] b) a step of exposing the substrate to co-reactant H2O;

[0086] c) a step of forming a BaO film by depositing at least a portion of an alkaline earth metal precursor onto a substrate through a vapor deposition process; and

[0087] d) a step of repeating a) to c) until a BaO film of the desired thickness is formed.

[0088] The disclosed deposition method may include one or more of the following features:

[0089] · The vapor deposition process is the MOCVD process;

[0090] · The vapor deposition process is an ALD process;

[0091] · The vapor deposition process is a thermal ALD, spatial ALD, temporal ALD, or plasma ALD process;

[0092] · The vapor deposition process is a thermal ALD process;

[0093] · The vapor deposition process is a spatial ALD process;

[0094] · The vapor deposition process is a temporal ALD process;

[0095] · The vapor deposition process is not a plasma ALD process;

[0096] · The vapor deposition process is a plasma ALD process;

[0097] The method further includes a step of separating each exposure step by purging the vapor of the excess Group II metal-containing film-forming composition and the excess co-reactant, respectively, using an inert gas such as N2, Ar, Kr, or Xe;

[0098] · Ba(sBu3Cp)2 is mixed with the solvent;

[0099] · The solvent in the mixture is in the range of 0% to approximately 50%;

[0100] · The solvent is a substituted or unsubstituted hydrocarbon selected from alkanes, alkenes, and alkynes; an alcohol selected from alkyl alcohols and amino alcohols; or an amine selected from primary, secondary, and tertiary amines; tetrahydrofuran; dichloromethane; ethyl acetate; butyl acetate; acetonitrile; and dimethylformamide;

[0101] · Hydrocarbons include octane, ethylbenzene, xylene, mesitylene, decalin, decane, and dodecane;

[0102] · The concentration of Ba(sBu3Cp)2 in the solvent varies;

[0103] · The concentration of Ba(sBu3Cp)2 in the solvent is in the range of approximately 50% w / w to approximately 100.0% w / w;

[0104] · The substrate is exposed to the precursor at a temperature ranging from room temperature to approximately 500°C;

[0105] · Ba(sBu3Cp)2 contains impurities of approximately 0.0% w / w to approximately 5.0% w / w;

[0106] · Ba(sBu3Cp)2 is purified to a purity of approximately 95 wt% or in the range of 95% w / w to approximately 100 w / w;

[0107] · Ba(sBu3Cp)2 is purified to a purity in the range of approximately 99% w / w to approximately 99.999% w / w; and

[0108] · Ba(sBu3Cp)2 is purified to a purity in the range of approximately 99% w / w to approximately 100% w / w.

[0109] Notation and Naming

[0110] The following detailed description and claims use many abbreviations, symbols, and terms commonly known in the art. Certain abbreviations, symbols, and terms are used throughout the following description and claims and include the following:

[0111] As used herein, the singular form ("a" or "an") means one or more.

[0112] As used herein, "about" or "around, approximately" in the text or claims means ±10% of the specified value.

[0113] As used herein, "room temperature" in the text or claims means approximately 20°C to approximately 25°C.

[0114] The term "ambient temperature" refers to an environment temperature of approximately 20°C to approximately 25°C.

[0115] It is noted herein that the terms "precursor," "deposited compound," and "deposited gas" may be used interchangeably when the precursor is in a gaseous state at room temperature and ambient pressure. It is understood that the precursor may correspond to or be related to the deposited compound or deposited gas, and that the deposited compound or deposited gas may refer to the precursor.

[0116] It is noted herein that the terms "deposition temperature" and "substrate temperature" may be used interchangeably. It is understood that the substrate temperature may correspond to or be related to the deposition temperature, and that the deposition temperature may refer to the substrate temperature.

[0117] It should be noted that deposited films or layers, such as silicon oxide or silicon nitride, may be listed throughout the specification and claims without mentioning the appropriate stoichiometry (i.e., SiO, SiO2, SiO3, Si3N4). The layer is an oxide (Si n O m It may include a ) layer or a mixture thereof, where m and n range from 1 to 6 (including the endpoint). For example, silicon oxide is Si n O m..., where n is in the range of 0.5 to 1.5 and m is in the range of 1.5 to 3.5. More preferably, the silicon oxide layer is SiO or SiO2. The silicon oxide layer may also be a silicon oxide-based dielectric material, such as an organic or silicon oxide-based low-k dielectric material, such as Black Diamond II or III material having the chemical formula SiOCH by Applied Materials, Inc. Alternatively, any mentioned silicon-containing layer may be pure silicon. The silicon-containing film may also be Si a O b C c N d H e It may include, where a, b, c, d, and e are in the range of 0.1 to 6, and each of b, c, d, and e may be independently 0. Alternatively, any silicon-containing layer may also include dopants such as B, C, P, As and / or Ge.

[0118] The term "substrate" refers to the material or materials on which the process is performed. The substrate may refer to a wafer having the material or materials on which the process is performed. The substrate may be any suitable wafer used in the manufacture of semiconductors, photovoltaics, flat panel, or LCD-TFT devices. The substrate may also have one or more layers of different materials already deposited in a previous manufacturing step. For example, the wafer may comprise a silicon layer (e.g., crystalline, amorphous, porous, etc.), a silicon-containing layer (e.g., SiO2, SiN, SiON, SiC, SiCN, SiOCN, SiCOH, etc.), a metal-containing layer (e.g., copper, cobalt, ruthenium, tungsten, manganese, platinum, palladium, nickel, ruthenium, gold, etc.), or a combination thereof. Additionally, the substrate may be planar or patterned. The substrate may be an organically patterned photoresist film. The substrate may comprise a layer of oxide used as a dielectric material (e.g., ZrO2-based materials, HfO2-based materials, TiO2-based materials, rare earth oxide-based materials, ternary oxide-based materials, etc.) in MEMS, 3D NAND, MIM, DRAM, or FeRam device applications, or a nitride-based film (e.g., TaN, TiN, NbN) used as an electrode. Those skilled in the art will recognize that as used herein, the terms “film” or “layer” refer to a portion of material of a certain thickness placed on or spread over a surface, and that said surface may be a trench or a line. Throughout this specification and claims, a wafer and any combined layer thereon are referred to as a substrate.

[0119] It should be noted that the terms “film” and “layer” may be used interchangeably herein. It is understood that a film may correspond to or be related to a layer, and that a layer may refer to a film. Furthermore, those skilled in the art will recognize that the terms “film” or “layer” as used herein refer to a portion of material of a certain thickness placed on or spread over a surface, and that said surface may range from large enough to be an entire wafer to small enough to be a trench or a line.

[0120] The terms “wafer,” “patterned wafer,” or “workpiece” refer to a wafer having a stack of films on a substrate, wherein at least the topmost film has topographic features formed prior to the deposition step of an indium-containing film. “Wafer” or “patterned wafer” refers to a wafer having a stack of films on a substrate and a patterned hard mask layer on the stack of films formed for pattern etching.

[0121] The term “process” as used herein includes patterning, exposure, development, etching, deposition, cleaning, and / or removal of by-products, such as those required to form the described structure.

[0122] The term "mask" refers to a layer that resists etching. The mask layer may be placed over the layer to be etched. The mask layer is also referred to as a hard mask layer.

[0123] The term "aspect ratio" refers to the ratio of the height of a trench (or opening) to the width (or diameter) of a trench.

[0124] The term "high aspect ratio (HAR)" refers to an aspect ratio in the range of approximately 1:1 to approximately 500:1, preferably approximately 20:1 to approximately 400:1.

[0125] The term "high aspect ratio etching" refers to forming a hole pattern on a target film by a plasma etching method when the aspect ratio of the formed hole structure is greater than 5.

[0126] It is noted that herein, the terms “opening,” “via,” “hole,” “trench,” and “structure” may be used interchangeably and generally refer to an opening formed in a semiconductor structure and / or an interlayer insulator.

[0127] The terms “dope” or “doping” are used interchangeably with the process of incorporating one or more elements into a film through various methods in which the elements may be chemically or physically bonded, and the process of intentionally incorporating atoms of different elements into a film composition. The element(s) may be doped into the film interstitially or substitutionally.

[0128] As used herein, the abbreviation "NAND" refers to a "Negated AND" or "Not AND" gate; the abbreviation "2D" refers to a two-dimensional gate structure on a planar substrate; and the abbreviation "3D" refers to a three-dimensional or vertical gate structure, wherein the gate structure is stacked in a vertical direction.

[0129] As used herein, the term “film-forming composition” refers to a mixture of components used for deposition that may contain precursors, catalysts, surfactants, wetting agents, and other polymers, oligomers, or monomers such as but not limited to polysilazane, polycarbosilane, polysilane, etc.

[0130] As used herein, the term "hydrocarbon" refers to a saturated or unsaturated functional group containing only carbon and hydrogen atoms. As used herein, the term "alkyl group" refers to a saturated functional group containing only carbon and hydrogen atoms. An alkyl group is a type of hydrocarbon. Additionally, the term "alkyl group" refers to a linear, branched, or cyclic alkyl group. Examples of linear alkyl groups include, without limitation, methyl groups, ethyl groups, propyl groups, butyl groups, etc. Examples of branched alkyl groups include, without limitation, t-butyl. Examples of cyclic alkyl groups include, without limitation, cyclopropyl groups, cyclopentyl groups, cyclohexyl groups, etc.

[0131] As used herein, the term "hydrofluorocarbon" refers to a saturated or unsaturated functional group containing only carbon, fluoride, and hydrogen atoms.

[0132] As used herein, the term "fluorocarbon" refers to a saturated or unsaturated functional group containing only fluoride and hydrogen atoms.

[0133] As used herein, the term "alkyl group" refers to a saturated functional group containing only carbon and hydrogen atoms. An alkyl group is a type of hydrocarbon. Additionally, the term "alkyl group" refers to a linear, branched, or cyclic alkyl group. Examples of linear alkyl groups include, without limitation, methyl groups, ethyl groups, propyl groups, butyl groups, etc. Examples of branched alkyl groups include, without limitation, t-butyl. Examples of cyclic alkyl groups include, without limitation, cyclopropyl groups, cyclopentyl groups, cyclohexyl groups, etc.

[0134] As used herein, the abbreviation "Me" refers to a methyl group; the abbreviation "Et" refers to an ethyl group; the abbreviation "Pr" refers to any propyl group (i.e., n-propyl or isopropyl); the abbreviation "iPr" refers to an isopropyl group; the abbreviation "Bu" refers to any butyl group (n-butyl, iso-butyl, tert-butyl, sec-butyl); the abbreviation "tBu" refers to a tert-butyl group; the abbreviation "sBu" refers to a sec-butyl group; the abbreviation "iBu" refers to an iso-butyl group; the abbreviation "Ph" refers to a phenyl group; the abbreviation "Am" refers to any amyl group (iso-amyl, sec-amyl, tert-amyl); The abbreviation "Cy" refers to a cyclic hydrocarbon group (cyclobutyl, cyclopentyl, cyclohexyl, etc.); the abbreviation "Ar" refers to an aromatic hydrocarbon group (phenyl, xylyl, mesithyl, etc.).

[0135] Standard abbreviations for elements from the periodic table are used herein. It should be understood that elements may be referred to by these abbreviations (e.g., Si refers to silicon, N refers to nitrogen, O refers to oxygen, C refers to carbon, H refers to hydrogen, F refers to fluorine, etc.).

[0136] The term "independently," when used in a context describing an R group, should be understood to mean that the target R group is selected not only independently of other R groups having the same or different subscripts or superscripts, but also independently of any additional chemical species of the same R group. For example, the chemical formula MR 1 x (NR 2 R 3 ) (4-x) (where M is an atom and x is 2 or 3), 2 or 3 R 1 Qi can be identical to each other or R 2 and or R 3It may be identical to, but not necessarily. Also, unless specifically stated otherwise, the values ​​of the R groups should be understood as independent of each other when used in different chemical formulas.

[0137] A range may be expressed herein as being from one approximate specific value and / or to another approximate specific value. When such a range is expressed, another embodiment should be understood as being from one specific value and / or to another specific value, together with all combinations within said range. Any and all ranges mentioned herein include their endpoints, regardless of whether the term "endpoint included" is used (i.e., x is 1 to 4, or x is a range from 1 to 4, including x is 1, x is 4, and x is any number in between).

[0138] "Optional" or "optional" means that the event or situation described subsequently may or may not occur. Such descriptions include cases where the event or situation occurs and cases where it does not occur.

[0139] References to “one embodiment” or “an embodiment” herein mean that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the present invention. Throughout this specification, the appearance of the phrase “in one embodiment” does not necessarily refer to the same embodiment, nor are separate or alternative embodiments necessarily mutually exclusive from other embodiments. The same applies to the term “an embodiment.”

[0140] As used in this application, the word "exemplary" is used to mean that it functions as an example, case, or illustration. Any mode or design described herein as "exemplary" is not to be interpreted as being more desirable or advantageous than any other mode or design. Rather, the use of the word "exemplary" is intended to provide the concept in a concrete manner.

[0141] Additionally, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or." That is, unless otherwise specified or is evident from the context, "X uses A or B" is intended to mean any natural inclusive permutation. In other words, if X uses A; if X uses B; or if X uses both A and B, "X uses A or B" is satisfied in any of these cases. Furthermore, the singular form used in this application and the appended claims should generally be construed to mean "one or more" unless otherwise specified or is evident from the context.

[0142] In the claims, “comprising” is an open transitional term, meaning that the elements of the claims identified thereafter are a non-exclusive enumeration (i.e., all other items may additionally be included and maintained within the scope of “comprising”). “Comprising” is defined herein as essentially including the more restrictive transitional terms “essentially composed of” and “composed of”; thus, “comprising” may be replaced by “essentially composed of” or “composed of” and is maintained within the explicitly defined scope of “comprising”.

[0143] In the claims, "providing" is defined as meaning supplying, providing, making available, or manufacturing something. A step may be carried out by any act unless otherwise clearly stated in the claims. Brief explanation of the drawing

[0144] To better understand the features and purposes of the present invention, reference will be made to the following detailed description in conjunction with the accompanying drawings, in which similar components are given the same or similar reference numbers: Fig. 1 This shows a thermogravimetric analysis (TGA) graph representing the weight percentage of bis(tri-sec-butylcyclopentadienyl)strontium(II), Sr(sBu3Cp)2 as a function of temperature increase. Fig. 2 This shows a differential thermal analysis (DTA) graph representing the melting point of bis(tri-sec-butylcyclopentadienyl)strontium(II), Sr(sBu3Cp)2. Fig. 3 This represents the differential scanning calorimetry (DSC) of bis(tri-sec-butylcyclopentadienyl)strontium(II), Sr(sBu3Cp)2. Fig. 4 This shows a TGA graph representing the weight percentage of bis(tri-sec-butylcyclopentadienyl)barium(II), Ba(sBu3Cp)2 as a function of temperature increase. Fig. 5 This shows a DTA graph representing the melting point of bis(tri-sec-butylcyclopentadienyl)barium(II), Ba(sBu3Cp)2. Fig. 6 This shows a DTA graph representing the melting point of bis(tri-iso-propylcyclopentadienyl)strontium(II), Sr(iPr3Cp)2. Fig. 7 This shows a DTA graph representing the melting point of bis(tri-tert-butylcyclopentadienyl)strontium(II), Sr(tBu3Cp)2. Fig. 8 This shows a DTA graph representing the melting point of bis(tri-iso-propylcyclopentadienyl)barium(II), Ba(iPr3Cp)2. Fig. 9represents a comparison table. Fig. 10 This represents the ALD window of bis(tri-sec-butylcyclopentadienyl)strontium(II), Sr(sBu3Cp)2. Specific details for implementing the invention

[0145] A composition for forming a film containing a Group II metal and a method for depositing a film using the same are disclosed. More specifically, a new class of thermally stable liquid Group II organometallic compounds and their use for depositing a Group II metal-containing film by an ALD or MOCVD process are disclosed.

[0146] Film-forming compositions containing group 2 metals may contain stereometallocenes, such as trialkyl-substituted cyclopentadienyl Ca, Sr, or Ba compounds, which are one of the most promising precursors for film deposition in superconductor and semiconductor fabrication due to their high volatility, thermal stability, stable monomer structure, and relatively low melting point.

[0147] However, most stereometallocenes are solid at room temperature. For example, the melting point of some exemplary stereometallocenes is graph 1 It is listed in.

[0148] [Table 1]

[0149]

[0150] In the case of solids, stereometallocenes generally have strong intermolecular forces and are tightly packed in regular patterns. Therefore, when the molecular structure has asymmetric ligands or long, flexible alkyl chains, disorder can be generated in the lattice packaging and the material tends to be liquid.

[0151] The disclosed Group II metal-containing film-forming composition comprises an alkaline earth metal precursor. The disclosed alkaline earth metal precursor can be developed by increasing the molecular degrees of freedom by introducing a linear alkyl chain, which is more flexible than iso-propyl or tert-butyl, into a cyclopentadienyl-alkaline earth metal compound.

[0152] The disclosed alkaline earth metal precursor has the following general chemical formula:

[0153]

[0154] (In the formula, M is Be, Mg, Ca, Sr, or Ba; R 1 to R 6 C1-C each independently 10 It is an alkyl group, a fluoro group, an alkylsilyl group, a germanyl group, an alkylamide, or an alkylsilylamide).

[0155] Exemplary alkaline earth metal precursors include bis(tri-sec-butyl cyclopentadienyl)strontium(II), Sr(sBu3Cp)2, bis(tri-sec-butyl cyclopentadienyl)barium(II), Ba(sBu3Cp)2, bis(tri-iso-propyl cyclopentadienyl)strontium(II), Sr(iPr3Cp)2, bis(tri-tert-butyl cyclopentadienyl)strontium(II), Sr(tBu3Cp)2, bis(tri-iso-propyl cyclopentadienyl)barium(II), Ba(iPr3Cp)2, etc.

[0156] The disclosed group 2 metal-containing film-forming composition comprises the liquid alkaline earth metal precursor bis(tri-sec-butylcyclopentadienyl)strontium(II), Sr(sBu3Cp)2.

[0157] The disclosed group 2 metal-containing film-forming composition comprises the liquid alkaline earth metal precursor bis(tri-sec-butylcyclopentadienyl)barium(II), Ba(sBu3Cp)2.

[0158] The disclosed group 2 metal-containing film-forming composition comprises the liquid alkaline earth metal precursor bis(tri-iso-propylcyclopentadienyl)strontium(II), Sr(iPr3Cp)2.

[0159] The disclosed group 2 metal-containing film-forming composition comprises the liquid alkaline earth metal precursor bis(tri-tert-butylcyclopentadienyl)strontium(II), Sr(tBu3Cp)2.

[0160] The disclosed group 2 metal-containing film-forming composition comprises the liquid alkaline earth metal precursor bis(tri-iso-propylcyclopentadienyl)barium(II) and Ba(iPr3Cp)2.

[0161] The disclosed alkaline earth metal precursor may be liquid at atmospheric pressure and may be suitable for the deposition of metal-containing films, such as SrO or BaO films, by vapor deposition methods such as ALD or MOCVD, and may have the following advantages:

[0162] Typically, the disclosed alkaline earth metal precursors generate fewer particles compared to solid precursors, even in solution; for example, no particles enter the precursor delivery line and the process wafer in the chamber. Additionally, the disclosed alkaline earth metal precursors extend the service life of the chamber compared to using solid precursors by reducing the frequency of chamber maintenance.

[0163] Liquid precursors have the advantage of delivering material very consistently due to a constant surface area inside the canister, compared to solid precursors, which aggregate over time during heating and exhibit variable particle surface areas, thereby generating non-uniform vapor pressure.

[0164] The disclosed alkaline earth metal precursor is ideally liquid and vaporized in a bubbler or direct liquid injection system, whereas the use of a solid precursor for ALD precursor vaporization is also possible using a conventional sublimator. Alternatively, the solid precursor can be mixed or dissolved in a solvent to reach a melting point and viscosity useful for use in a direct liquid injection system. Alternatively, the liquid precursor can also be mixed with a solvent to lower the viscosity.

[0165] The solvent may be a substituted or unsubstituted hydrocarbon, e.g., alkanes, alkenes, alkynes, etc.; an alcohol, e.g., alkyl alcohols, amino alcohols, etc.; or an amine, e.g., primary, secondary, or tertiary amines; tetrahydrofuran; dichloromethane; ethyl acetate; butyl acetate; acetonitrile; or dimethylformamide. Hydrocarbons may include octane, ethylbenzene, xylene, mesitylene, decalin, decane, dodecane, etc. The concentration of the alkaline earth metal precursor in the solvent varies, for example, the concentration of the alkaline earth metal precursor in the solvent may be in the range of approximately 50% w / w to approximately 100.0% w / w. Preferably, the solvent contained in the mixture of the liquid precursor and the solvent is in the range of 0% to approximately 50%.

[0166] The disclosed metal-containing film-forming composition may include an alkaline earth metal precursor in an amount of approximately 50% w / w to approximately 100.0% w / w.

[0167] To ensure process reliability, the disclosed alkaline earth metal precursor can be purified before use by continuous or fractional batch distillation or sublimation to a purity of approximately 95 wt% or in the range of 95% w / w to approximately 100% w / w, preferably in the range of approximately 99% w / w to approximately 99.999% w / w, more preferably in the range of approximately 99% w / w to approximately 100% w / w.

[0168] The disclosed alkaline earth metal precursor may contain any of the following impurities: unwanted homologous species; solvents; metal chloride compounds; or other reaction products. In one alternative, the total amount of these impurities is less than 5.0% w / w, preferably less than 0.1% w / w.

[0169] Solvents such as hexane, pentane, dimethyl ether, or anisole may be used for the synthesis of the precursor. The concentration of the solvent in the disclosed metal-containing precursor may be in the range of approximately 0% w / w to approximately 5% w / w, preferably approximately 0% w / w to approximately 0.1% w / w. Separation of the solvent from the precursor may be difficult if both have similar boiling points. Cooling of the mixture may produce a solid precursor in the liquid solvent, which can be separated by filtration. Additionally, vacuum distillation may be used, provided that the precursor product is not heated above its approximately decomposition point.

[0170] In one alternative, the disclosed alkaline earth metal precursor contains any of the unwanted homologous species, reactants, or other reaction products in an amount of less than 5% v / v, preferably less than 1% v / v, more preferably less than 0.1% v / v, and even more preferably less than 0.01% v / v. This alternative may provide better process repeatability. This alternative may be produced by distillation of the disclosed alkaline earth metal precursor.

[0171] In other alternatives, particularly when the mixture provides improved process parameters or when the separation of the target compound is too difficult or costly, the disclosed alkaline earth metal precursor may contain one or more of homologous metal-containing precursors, reactants, or other reaction products in an amount of 5% v / v to 50% v / v. For example, a mixture of two alkaline earth metal precursors can produce a stable liquid mixture suitable for vapor deposition.

[0172] In another alternative, the disclosed alkaline earth metal precursor may contain metal impurities of approximately 0 ppbw to approximately 500 ppbw.

[0173] The concentrations of trace metals and metalloids in the disclosed alkaline earth metal precursor may each be in the range of approximately 0 ppb to approximately 100 ppb, more preferably approximately 0 ppb to approximately 10 ppb.

[0174] In addition to the disclosed alkaline earth metal precursor, a reactant or co-reactant may also be introduced into the reaction chamber. The co-reactant may be an oxygen-containing gas or a nitrogen-containing gas for metal oxide film deposition. The co-reactant may contain an oxidizing agent, such as O3, O2, H2O, H2O2, D2O, or ROH (where R is C1-C 10 Includes, but is not limited to, linear or branched hydrocarbons.

[0175] The ALD sequence may include sequential pulses of several compounds. For example, the surface may be exposed to O2 / O3 followed by H2O to increase the density of hydroxyl groups on the surface.

[0176] Alternatively, the co-reactant may be a nitrogen-containing gas for depositing a nitrogen-containing film. Nitrogen-containing gases include, but are not limited to, NH3, NO, N2O, hydrazine, primary amines such as methylamine, ethylamine, tert-butylamine; secondary amines such as dimethylamine, diethylamine, di-isopropylamine, ethylmethylamine, pyrrolidine; tertiary amines such as trimethylamine, triethylamine, trisilylamine, N2, and N2 / H2 mixtures thereof, preferably NH3. The co-reactant may be selected from NH3, NO, N2O, hydrazine, amines, or combinations thereof.

[0177] A method or process for forming a Group 2 metal-containing film on a substrate through a vapor deposition process is also disclosed. In one embodiment, a method for forming a Group 2 metal-containing film on a substrate comprises: a) providing a substrate to a reaction chamber; b) exposing the substrate to a vapor comprising a disclosed Group 2 metal-containing film-forming composition containing a disclosed alkaline earth metal precursor; c) forming a Group 2 metal-containing film by depositing at least a portion of the disclosed alkaline earth metal precursor on the substrate through a vapor deposition process; and repeating b) and c) until a Group 2 metal-containing film of a desired thickness is formed.

[0178] This method further comprises a step of exposing the substrate to a co-reactant after step b), wherein the co-reactant is O3, O2, H2O, H2O2, D2O, ROH (R is C1-C 10 It is selected from (linear or branched) hydrocarbons), NH3, NO, N2O, hydrazine, amines, or combinations thereof. For example, one of the above co-reactants or a combination thereof may be used to deposit a silicon oxynitride film by flowing the co-reactants simultaneously or sequentially.

[0179] In an alternative embodiment, a method for forming a Group 2 metal-containing film on a substrate comprises: a) providing a substrate in a reaction chamber; b) exposing the substrate to the vapor of a disclosed Group 2 metal-containing film-forming composition containing a disclosed alkaline earth metal precursor, such as bis(tri-sec-butylcyclopentadienyl)strontium(II), Sr(sBu3Cp)2, bis(tri-sec-butylcyclopentadienyl)barium(II), Ba(sBu3Cp)2, bis(tri-iso-propylcyclopentadienyl)strontium(II), Sr(iPr3Cp)2, bis(tri-tert-butylcyclopentadienyl)strontium(II), Sr(tBu3Cp)2, bis(tri-iso-propylcyclopentadienyl)barium(II), and Ba(iPr3Cp)2; and c) depositing a Group 2 metal-containing film on the substrate in a vapor deposition process. This method includes. The method further includes the step of exposing the substrate to a co-reactant after step b), wherein the co-reactant is O3, O2, H2O, H2O2, D2O, ROH (R is C1-C 10 (It is a linear or branched) hydrocarbon), selected from NH3, NO, N2O, hydrazine, amine, or a combination thereof. The method further comprises the steps of repeating the steps of exposing to the vapor of a Group II metal-containing film-forming composition and exposing to a co-reactant until a Group II metal-containing film of desired thickness is formed, and separating each exposure step by purging the excess vapor of the Group II metal-containing film-forming composition and the excess co-reactant, respectively, using an inert gas which is N2, Ar, Kr, or Xe.

[0180] The disclosed process using the disclosed alkaline earth metal precursor includes an ALD process for depositing a film containing a Group II metal. Suitable ALD methods include thermal ALD, spatial ALD, and temporal ALD methods. Suitable ALD methods may also include plasma ALD methods. Preferably, suitable ALD methods do not use plasma because it is very difficult to grow conformal films with high aspect ratios using this type of ALD. Suitable ALD is understood to operate as an imperfect self-limiting growth technique, which may cause some parasitic CVD. Such parasitic CVD may not be a problem as long as the deposited film meets conformal requirements.

[0181] The disclosed process using the disclosed alkaline earth metal precursor also includes an MOCVD process for depositing a Group II metal-containing film.

[0182] The reaction chamber may be any enclosure or chamber of the device in which the deposition method is performed, such as a parallel plate reaction chamber, a high-temperature wall reaction chamber, a single wafer reaction chamber, a multi-wafer reaction chamber, or other such types of deposition systems, without limitation. All of these exemplary reaction chambers can serve as an ALD reaction chamber.

[0183] The reaction chamber accommodates one or more substrates on which a film is to be deposited. A substrate is generally defined as the material on which the process is performed. Before deposition, the substrate is cleaned to remove inherent oxides and dried. The substrate may be any suitable substrate used in the manufacture of semiconductors, photovoltaics, flat panel, or LCD-TFT devices. Examples of suitable substrates include wafers, such as metals (e.g., W, Ge, etc.), silicon, SiGe, silica, or glass. The substrate may also have one or more surface regions of different materials already deposited in a previous manufacturing step. For example, the wafer may include dielectric surfaces and conductive or electrode surfaces that are simultaneously exposed, such as metal surfaces, metal oxide surfaces, silicon surfaces, silicon layers (crystalline, amorphous, porous, etc.), silicon oxide layers / surfaces, silicon nitride layers / surfaces, silicon oxynitride layers / surfaces, carbon-doped silicon oxide (SiCOH) layers / surfaces, or combinations thereof. Additionally, the wafer may comprise a layer of copper, cobalt, ruthenium, tungsten, and / or other metals (e.g., platinum, palladium, nickel, ruthenium, or gold). The wafer may comprise a barrier layer or an electrode, such as tantalum, tantalum nitride, etc. The wafer may be planar or patterned. The substrate may comprise a layer of oxide with an exposed oxide surface used as a dielectric material (e.g., ZrO2-based material, HfO2-based material, TiO2-based material, rare earth oxide-based material, ternary oxide-based material, etc.) in 3D NAND, MIM, DRAM, or FeRam technology, or a nitride-based film (e.g., TaN, TiN, NbN) used as an electrode. The disclosed process may deposit the metal-containing layer directly onto the wafer, or directly onto one or more of the top layers of the wafer (where the patterned layer forms the substrate).Furthermore, those skilled in the art will recognize that as used herein, the terms “film” or “layer” refer to a portion of material of a certain thickness placed on or spread over a surface, and that said surface may be a trench or a line. Throughout this specification and claims, a wafer and any combined layer / surface thereon are referred to as a substrate. Additionally, the actual substrate used may vary depending on the specific precursor embodiment used.

[0184] The disclosed process using the disclosed alkaline earth metal precursor can be performed on a substrate having a temperature range from room temperature to approximately 500°C.

[0185] The temperature of the reaction chamber can be controlled by controlling the temperature of the substrate holder or by controlling the temperature of the reaction chamber walls. Devices used to heat the substrate are known in the art. The reaction chamber walls are heated to a temperature sufficient to obtain a desired film having a desired physical state and composition at a sufficient growth rate. Non-limiting exemplary temperature ranges in which the reaction chamber walls may be heated include room temperature to approximately 500°C.

[0186] In the disclosed process using the disclosed precursor, the substrate exposure time in the reaction chamber may be in the range of 1 millisecond to 5 minutes, preferably 1 millisecond to 60 seconds. In the disclosed process, the co-reactant exposure time in the reaction chamber may be in the range of 1 millisecond to 1 minute, preferably 100 milliseconds to 30 seconds.

[0187] The pressure inside the reaction chamber is maintained at a condition suitable for the precursor to react with the surface of the substrate. For example, the pressure inside the chamber can be maintained at approximately 0.1 mTorr to approximately 1000 Torr, preferably approximately 1 mTorr to approximately 400 Torr, more preferably approximately 0.1 Torr to approximately 100 Torr, and even more preferably approximately 0.5 Torr to approximately 10 Torr.

[0188] The disclosed process or sequence typically includes a step of removing excess precursor and excess co-reactant from a deposition surface by providing a purging step by purging a reaction chamber with an inert gas or by passing a substrate through a sector under a high vacuum and / or carrier gas curtain. The inert gas is N2, Ne, Ar, Kr, or Xe, preferably N2 or Ar.

[0189] The disclosed alkaline earth metal precursor and co-reactant can be introduced sequentially into the reaction chamber (ALD). The reaction chamber can be purged with an inert gas between the introduction of the precursor and the introduction of the co-reactant, and after the introduction of the co-reactant. Alternatively, the substrate can be moved from one area for precursor exposure to another area for co-reactant exposure (spatial ALD).

[0190] Deposition can occur for various lengths of time depending on specific process parameters. Generally, deposition can be continued as long as desired or required to produce a film with the required thickness. Typical film thicknesses can vary from an atomic monolayer to several hundred microns, preferably 0.1 to 100 nm, and more preferably 0.1 to 50 nm, depending on the specific deposition process. Additionally, the deposition process can be performed multiple times as needed to obtain the desired film.

[0191] In one non-limiting exemplary ALD process, the vapor phase of the initiated alkaline earth metal precursor is introduced into a reaction chamber, whereby the alkaline earth metal precursor is physically or chemically adsorbed onto a substrate. Subsequently, excess composition may be removed from the reaction chamber by purging and / or evacuating the reaction chamber. A desired gas (e.g., an oxidizing agent H2O or O3) is introduced into the reaction chamber, whereby it reacts with the physically or chemically adsorbed precursor in a self-limiting manner. Any excess oxidizing agent gas is removed from the reaction chamber by purging and / or evacuating the reaction chamber.

[0192] Examples

[0193] The following non-limiting examples are provided to further illustrate embodiments of the present invention. However, the examples are not intended to be all-encompassing, nor are they intended to limit the scope of the invention as described herein.

[0194] Example 1 Synthesis of bis(tri-sec-butylcyclopentadienyl)strontium(II), Sr(sBu3Cp)2

[0195]

[0196] A solution of K(sBu3Cp) (3.3 g, 12.11 mmol) was added dropwise to a solution of SrI2 (1.88 g, 5.51 mmol) in 30 mL of THF at -30°C. The reaction mixture was slowly heated to room temperature overnight while stirring. After filtration, the solvent was removed under reduced pressure to obtain a brown liquid. Subsequently, the material was purified by distillation at 25 mTorr to 130°C, yielding 1.2 g (40.0%) of yellow oil. The material [was NMR] 1 H (δ, ppm, C6D6): was characterized as 5.62 (m, 4H), 2.57 (m, 6H), 1.52 (m, 12H), 1.34, 1.18 (m, 18H), 0.96, 0.88 (m, 18H).

[0197] The purified product left 3.8% residue during open-cup TGA / DTA analysis measured at a temperature rise rate of 10°C / min in an inert atmosphere with nitrogen flowing at 200 mL / min, and no melting point was observed. These results Fig. 1 and Fig. 2 These are shown in [figure], and are TGA and DTA graphs representing weight (%) and heat flow with increasing temperature. The product decomposition onset temperature (430°C) was measured by differential scanning calorimetry (DSC), and this Fig. 3 It appears in.

[0198] Fig. 10 This shows the ALD window of bis(tri-sec-butylcyclopentadienyl)strontium(II), Sr(sBu3Cp)2. The pyrolysis test showed that the precursor Sr(sBu3Cp)2 is stable up to 450°C and decomposes above 500°C. This indicates that the new Sr precursor is thermally stable, allowing SrO thin films to be deposited by a high-temperature process using ozone.

[0199] Example 2 Synthesis of bis(tri-sec-butylcyclopentadienyl)barium(II), Ba(sBu3Cp)2

[0200]

[0201] A solution of K(sBu3Cp) (3.2 g, 11.76 mmol) was added dropwise to a solution of BaI2 (2 g, 5.1 mmol) in 30 mL of THF at -30°C. The reaction mixture was slowly heated to room temperature overnight while stirring. After filtration, the solvent was removed under reduced pressure to obtain a brown liquid. Subsequently, the material was purified by distillation at 25 mTorr to 130°C, yielding 1.0 g (32.5%) of yellow oil. The material [was NMR] 1H (δ, ppm, C6D6): was characterized as 5.5 (m, 4H), 2.63 (m, 6H), 1.66, 1.54 (m, 12H), 1.27, 1.20 (m, 18H), and 0.99 (m, 18H).

[0202] The purified product left 2.7% residue during open-cup TGA / DTA analysis measured at a temperature rise rate of 10°C / min in an inert atmosphere with nitrogen flowing at 200 mL / min, and no melting point was observed. These results Fig. 4 and Fig. 5 These are shown in the TGA and DTA graphs representing weight (%) and heat flow as temperature increases.

[0203] Comparative Example 1 Bis(tri-iso-propylcyclopentadienyl)strontium(II), Sr(iPr3Cp)2

[0204]

[0205] The melting point was found to be 44°C during an open-cup DTA analysis measured at a temperature rise rate of 10°C / min in an inert atmosphere with nitrogen flowing at 200 mL / min. These results Fig. 6 It is shown in, and this is a DTA graph showing heat flow according to the increase in temperature.

[0206] Comparative Example 2 Bis(tri-tert-butylcyclopentadienyl)strontium(II), Sr(tBu3Cp)2

[0207]

[0208] The melting point was found to be 143°C during an open-cup DTA analysis measured at a temperature rise rate of 10°C / min in an inert atmosphere with nitrogen flowing at 200 mL / min. These results Fig. 7 It is shown in, and this is a DTA graph showing heat flow according to the increase in temperature.

[0209] Comparative Example 3Bis(tri-iso-propylcyclopentadienyl)barium(II), Ba(iPr3Cp)2

[0210]

[0211] The melting point was found to be 92°C during an open-cup DTA analysis measured at a temperature rise rate of 10°C / min in an inert atmosphere with nitrogen flowing at 200 mL / min. These results Fig. 8 It is shown in, and this is a DTA graph showing heat flow according to the increase in temperature.

[0212] The pyrolysis test showed that the precursor is stable up to 450°C and decomposes above 500°C. This indicates that the new Sr precursor is thermally stable, allowing SrO films to be deposited by a high-temperature process using ozone. Fig. 9 represents a comparison table.

[0213] It will be understood that numerous additional modifications to the details, materials, steps, and arrangements of parts described and illustrated herein to illustrate the essence of the invention may be made by those skilled in the art within the principles and scope of the invention as set forth in the appended claims. Accordingly, the invention is not limited to the foregoing embodiments and / or specific embodiments of the accompanying drawings.

[0214] Although embodiments of the present invention have been presented and described, modifications thereof may be made by those skilled in the art without departing from the spirit or teaching of the present invention. The embodiments described herein are merely illustrative and non-limiting. Many changes and modifications to the composition and method are possible within the scope of the present invention. Accordingly, the scope of protection is not limited to the embodiments described herein, but is limited only by the following claims, the scope of which includes all equivalents to the subject matter of the claims.

Claims

Claim 1 A method for forming a Group 2 metal-containing film on a substrate, comprising: a) exposing the substrate to the vapor of a Group 2 metal-containing film-forming composition containing an alkaline earth metal precursor having the following chemical formula; (In the formula, M is Be, Mg, Ca, Sr, or Ba; R 1 to R 6 C1-C each independently 10 a) an alkyl group, a fluoro group, an alkylsilyl group, a germanyl group, an alkylamide, or an alkylsilylamide; b) a step of forming a group 2 metal-containing film by depositing at least a portion of the alkaline earth metal precursor on the substrate through a vapor deposition process; and c) a step of repeating a) and b) until a group 2 metal-containing film of a desired thickness is formed. Claim 2 A method according to claim 1, further comprising the step of exposing the substrate to a co-reactant selected from an oxidizing agent or a nitrating agent. Claim 3 In paragraph 2, the above co-reactants are O3, O2, H2O, H2O2, D2O, ROH (where R is C1-C 10 A method selected from linear or branched hydrocarbons) or a combination thereof. Claim 4 In paragraph 2, the method wherein the co-reactant is selected from NH3, NO, N2O, hydrazine, amine, or a combination thereof. Claim 5 In paragraph 2, the method wherein the co-reactant is H2O. Claim 6 A method according to claim 1, wherein the alkaline earth metal precursor is a liquid. Claim 7 A method of mixing the alkaline earth metal precursor with a solvent in accordance with claim 1. Claim 8 The method of claim 7, wherein the solvent is a substituted or unsubstituted hydrocarbon selected from alkanes, alkenes, and alkynes; an alcohol selected from alkyl alcohols and amino alcohols; or an amine selected from primary, secondary, and tertiary amines; tetrahydrofuran; dichloromethane; ethyl acetate; butyl acetate; acetonitrile; and dimethylformamide. Claim 9 A method according to any one of claims 1 to 8, wherein the substrate is exposed to the vapor of the Group 2 metal-containing film-forming composition at a temperature ranging from room temperature to approximately 500°C. Claim 10 A method according to any one of claims 1 to 8, wherein the alkaline earth metal precursor is selected from the group consisting of bis(tri-sec-butyl cyclopentadienyl)strontium(II), Sr(sBu3Cp)2, bis(tri-sec-butyl cyclopentadienyl)barium(II), Ba(sBu3Cp)2, bis(tri-iso-propyl cyclopentadienyl)strontium(II), Sr(iPr3Cp)2, bis(tri-tert-butyl cyclopentadienyl)strontium(II), Sr(tBu3Cp)2, bis(tri-iso-propyl and cyclopentadienyl)barium(II), and Ba(iPr3Cp)2. Claim 11 A method according to any one of claims 1 to 8, wherein the alkaline earth metal precursor is bis(tri-sec-butylcyclopentadienyl)strontium(II), Sr(sBu3Cp)2. Claim 12 A method according to any one of claims 1 to 8, wherein the alkaline earth metal precursor is bis(tri-sec-butylcyclopentadienyl)barium(II) or Ba(sBu3Cp)2. Claim 13 A method according to any one of claims 1 to 8, wherein the vapor deposition process is an ALD process selected from a MOCVD process, or a thermal ALD, spatial ALD, temporal ALD, or plasma ALD process. Claim 14 A method for depositing an SrO film on a substrate, comprising: a) exposing the substrate to vapor of bis(tri-sec-butylcyclopentadienyl)strontium(II), Sr(sBu3Cp)2; b) exposing the substrate to co-reactant H2O; c) forming the SrO film by depositing at least a portion of the alkaline earth metal precursor on the substrate through a vapor deposition process; and d) repeating a) to c) until the SrO film of a desired thickness is formed. Claim 15 A method for depositing a BaO film on a substrate, comprising: a) exposing the substrate to vapor of bis(tri-sec-butylcyclopentadienyl)barium(II), Ba(sBu3Cp)2; b) exposing the substrate to co-reactant H2O; c) forming the BaO film by depositing at least a portion of the alkaline earth metal precursor on the substrate through a vapor deposition process; and d) repeating a) to c) until the BaO film of a desired thickness is formed.

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