Hydrogenated silicon heteropyrrole, hydrogenated silicon azapyrrole, thiosilanol, preparation method thereof and obtained reaction product

Abstract

Hydrogenated silicon heteropyrroles and hydrogenated silicon azapyrroles are a new class of heterocyclic compounds in which silicon is bonded to carbon and nitrogen atoms in the ring system, and one or two hydrogen atoms are attached to the silicon atom. These compounds are represented by formula (I), wherein R is a substituted or unsubstituted organic group and R' is an alkyl group. These compounds react with various organic and inorganic hydroxyl groups through ring-opening reactions and can be used to produce silicon nitride or silicon carbonitride films. #imgabs0#

Description

[0001] The present application is a divisional application of the invention patent application with the application date of June 9, 2016, the application number of 201680035325.0, and the invention name of “Hydrogenated silicon heteropyrrole, hydrogenated silicon azapyrrole, thiosilanol, preparation method thereof and obtained reaction product”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims priority to U.S. Provisional Application No. 62 / 180,351, filed June 16, 2015, the entire contents of which are incorporated herein by reference. Background of the Invention

[0004] Currently, there is great interest in molecular layer deposition for nano-featured devices including semiconductors and microelectromechanical systems (MEMS). Rapid and preferably quantitative deposition of monolayers with minimal byproducts is desirable. Silicon carbonitride films are of particular interest for various dielectric, passivation, and etch-stop applications.

[0005] Examples of known systems for producing silicon nitride or silicon carbonitride films include the use of trisilylamine ((SiH3)3N) and an inert gas and, optionally, ammonia as described in U.S. Patent No. 4,200,666; the system of diethylsilane and ammonia in an LPCVD system at 800°C as described by A. Hochberg et al. ((Mat. Res. Soc. Symp, 24, 509 (1991)); and the system of cyclic silazanes and ammonia in a chemical vapor deposition (CVD) method described by B. Arkles (J. Electrochemical Soc., Vol. 133, No. 1, pp. 233-234 (1986)).

[0006] Recently, halide-containing precursors such as tetraiodosilane and hexachlorodisilane were described in U.S. Pat. No. 6,586,056 and by M. Tanaka et al. (J. Electrochemical Society, 147, 2284 (2000). Unfortunately, there are operational difficulties associated with the corrosive nature of the precursors, as well as membrane fouling and byproducts.

[0007] Another approach is to use bis(tert-butylamino)silane, which produces SiN films of reasonable quality at temperatures as low as 550° C. (J. Gumpher et al., J. Electrochem. Soc., 151, G353 (2004)) or plasma-assisted pulsed deposition as described in U.S. Patent Application Publication No. 2011 / 0256734. In both cases, there are difficulties with carbon contamination of the film and the high energy requirements of the thermal and plasma states, which are incompatible with substrate stability. A review of alternative methods is found in EP 2644609 A2, which proposes fluorinated precursors. Although such fluorinated precursors theoretically allow lower deposition temperatures, the introduced fluorine often affects the electrical properties of the silicon-based structure.

[0008] Known cyclic azasilanes contain alkyl (e.g., methyl) or alkoxy (e.g., ethoxy) substituents on the silicon atom (see B. Arkles et al., "Cyclic Azasilanes: Volatile Coupling Agents for Nanotechnology," in Silanes and Other Coupling Agents, Vol. 3, K. Mittal (ed.), VSP (Brill), pp. 179-191 (2004)). In the main applications of interest, these compounds are unacceptable because they either contain excess carbon or introduce oxygen into the film due to substitution of the ring silicon atom. Consequently, there remains an unmet need for new silicon nitride and silicon carbonitride precursors for depositing silicon nitride at low temperatures. Summary of the Invention

[0009] In one embodiment of the present invention, hydridosilapyrroles or hydridosilaazapyrroles are represented by formula (I):

[0010]

[0011] wherein R is a substituted or unsubstituted organic group having a carbon or silicon atom bonded to the pyrrole ring nitrogen and R' is an alkyl group.

[0012] A method for preparing a silanol or silanol azapyrrole of formula (I):

[0013]

[0014] Wherein R is a substituted or unsubstituted organic group having a carbon or silicon atom bonded to the pyrrole ring nitrogen and R' is an alkyl group, the method comprises reducing a cyclic azasilane having an alkoxide group on the silicon.

[0015] A thiasilacyclopentane of formula (II):

[0016]

[0017] wherein R" and R"' are independently hydrogen or alkyl. Detailed Description of the Invention

[0018] The present invention relates to a new class of cyclic azasilanes, termed hydridosilanes (or cyclic azasilylhydrides) and hydridozyrroles. Unlike known cyclic azasilanes that contain alkyl or alkoxy substituents on the silicon atom, the materials of the present invention are hydridosilanes that can reduce or eliminate carbon and oxygen components from the substituents on the silicon atom.

[0019] The hydridosilapyrroles and hydridoazapyrroles of the present invention have a general structure as shown in formula (I):

[0020]

[0021] The key features of these compounds include a five-atom ring structure in which a silicon atom is bonded to a carbon atom and a nitrogen atom and at least one hydrogen atom is bonded to the silicon atom. As shown in formula (I), the nitrogen can be bonded to a carbon atom or a second nitrogen atom in the ring to form a cyclic diazasilane (also known as a hydrosilazapyrrole or diazasilacyclopentane).

[0022] In formula (I), R can be any substituted or unsubstituted organic group, wherein carbon or silicon is bonded to the ring nitrogen. Exemplary groups include, but are not limited to, alkyl, aryl, ester, chiral organic group and trimethylsilyl. Preferably, it is a small hydrocarbyl (including phenyl) and a nitrogen-substituted hydrocarbon with up to six carbon atoms, such as dimethylaminoethyl. R' can be any alkyl, preferably with up to about twenty carbon atoms, more preferably less than about six carbon atoms, most preferably methyl, ethyl, propyl or butyl.

[0023] Simple specific examples of compounds of the present invention include N-methyl-2-silapyrrole and N-butyl-2-silapyrrole:

[0024]

[0025] Other examples include those with more complex functional substituents on the nitrogen, including chiral phenylethylamines, trimethylsilyl groups, and tertiary amine groups.

[0026]

[0027] In one embodiment, the ring structure further contains an additional nitrogen atom at the 3-position to form a cyclic diazasilane. Two exemplary cyclic diazasilanes include:

[0028]

[0029] The present invention also relates to a method for preparing the above-mentioned silanols. The method involves reducing the corresponding cyclic azasilane having an alkoxy group substituted on the silicon atom, as shown in the following exemplary scheme:

[0030]

[0031] Therefore, the only limitation on the hydridosilapyrroles that can be produced by the process of the present invention is the ability to synthesize alkoxy-containing precursors.

[0032] The materials of the present invention react quantitatively via ring-opening reactions with inorganic and organic hydroxyl groups, including those on siliceous, aluminum, and titanium substrates, as shown below, as well as with organic hydroxyl groups, including alcohols.

[0033]

[0034] These species can also react with isolated silanols (eg, triethylsilanol) in homogeneous solution, as well as with other protic species including amines and thiols.

[0035] Depending on the desired end product, the silyl hydride functionality can remain intact or can be dehydrogenated to form silicon carbonitride, can be used as a regiospecific reducing agent, or can undergo hydrosilylation. Thus, the materials of the present invention are attractive for many applications, including the formation of silicon nitride and silicon carbonitride films.

[0036] The present invention also relates to a new class of thiosilanol compounds as shown in formula (II):

[0037]

[0038] In formula (II), R" and R' are independently hydrogen or an alkyl group containing one to about twenty carbon atoms, most preferably hydrogen or methyl. A preferred compound of this class is 1-thia-2-silacyclopentane as shown below; other preferred or exemplary compounds of this class are also shown below. In these structures, R" and R' are preferably hydrogen or methyl:

[0039]

[0040] Thiosilacyclopentane undergoes a surface reaction with hydroxyl groups to produce a film containing thiol groups. The thiol groups formed in this reaction can react with olefins or other mercapto compounds to further modify the surface.

[0041] The synthesis of the thiosilacyclopentane compounds of the present invention is described by methods similar to those described above for producing hydrosilapyrroles: by reducing a thiosilacyclopentane compound having an alkoxy group on silicon. For example, 1-thia-2-silacyclopentane is prepared from 2,2-alkoxy-1-thia-2-silacyclopentane as a starting material, as shown below:

[0042]

[0043] The invention will now be described with reference to the following non-limiting examples.

[0044] Example 1: Synthesis of N-butyl-2-silapyrrole (n-butylazasilacyclopentane)

[0045]

[0046] Under an argon atmosphere, 400 ml of 2-methyltetrahydrofuran was added to a 2-liter, 4-necked flask equipped with a cooling bath, mechanical stirrer, kettle thermometer, addition funnel, and dry ice distillation head. Subsequently, 25.3 g (0.67 mol) of lithium aluminum hydride was added portionwise. The mixture was cooled to -10°C and maintained at -5 to 0°C. Over a period of 2 hours, 203.4 g (1.0 mol) of N-n-butyl-aza-dimethoxysilylcyclopentane was added via the addition funnel. After the addition was complete, the kettle mixture was maintained at 0°C for approximately 2 hours. 345 g of mineral oil was added to the kettle. The kettle mixture was stirred at a kettle temperature of 80°C and 0.5 mmHg. The crude product was redistilled under reduced pressure to obtain 68.1 g (yield 48%) of the title compound, bp: 60-2 / 25 mmHg, density @ 20°C: 0.783, FTIR: vS-H: 2120.0 (vs).

[0047] Example 2: N-(3-dimethylaminopropyl)-2-methyl-2-silanopyrrole (N-dimethylaminopropyl-aza-1- Synthesis of Methyl-Silylcyclopentane

[0048]

[0049] Under an argon atmosphere, 300 ml of 2-methyltetrahydrofuran was added to a 2-liter, 4-necked flask equipped with a cooling bath, a mechanical stirrer, a kettle thermometer, an addition funnel, and a dry ice distillation head. Then, 9.5 g (0.25 mol) of lithium aluminum hydride was added portionwise. The mixture was cooled to -10°C and maintained at -5 to 0°C. Over a period of 2 hours, 162.3 g (0.75 mol) of N-n-dimethylaminopropyl-aza-methylmethoxysilylcyclopentane was added via the addition funnel. After the addition was complete, the kettle mixture was maintained at 0°C for approximately 2 hours. 260 g of mineral oil was added to the kettle. The kettle mixture was stirred at a kettle temperature of 80°C and 0.5 mmHg. The crude product was redistilled under reduced pressure to yield the title compound, bp: 52-4 / 0.5 mmHg, density @ 20°C: 0.857, FTIR: vS-H: 2111 (vs).

[0050] Example 3: N-trimethylsilyl-2-silapyrrole (N-trimethylsilyl-aza-1-methyl-silapyrrole Synthesis of pentane

[0051]

[0052] Under an argon atmosphere, a 2-liter, 4-necked flask equipped with a cooling bath, mechanical stirrer, kettle thermometer, addition funnel, and dry ice distillation head was charged with 400 ml of 2-methyltetrahydrofuran, followed by the portionwise addition of 25.3 g (0.67 mol) of lithium aluminum hydride. The mixture was cooled to -10°C and maintained at -5 to 0°C. Over a period of 2 hours, 203.4 g (1.0 mol) of N-trimethylsilyl-aza-dimethoxysilanol was added via the addition funnel. After the addition was complete, the kettle mixture was maintained at 0°C for approximately 2 hours. 345 g of mineral oil was added to the kettle. The kettle mixture was stirred at a kettle temperature of 80°C and 0.5 mmHg. The crude product was then distilled under reduced pressure to yield the title compound, bp: 48-50 / 10 mmHg, density @ 20°C: 0.846, FTIR: vS-H: 2120 (vs).

[0053] Example 4: Synthesis of 1-thia-2-silacyclopentane

[0054]

[0055] Under an argon atmosphere, a 2-liter, four-necked flask equipped with a cooling bath, mechanical stirrer, kettle thermometer, addition funnel, and dry ice distillation head was charged with 490 ml of diglyme, followed by portionwise addition of 27.8 g (0.0.73 mol) of lithium aluminum hydride. The mixture was cooled to -10°C and maintained between -5 and 0°C. Over 2 hours, 200.4 g (1.22 mol) of 2,2-dimethoxy-1-thia-2-silacyclopentane was added via the addition funnel. After the addition was complete, the kettle mixture was maintained at 0°C for approximately 2 hours. The kettle mixture was stirred at 80°C and 0.5 mmHg. The crude product was redistilled under reduced pressure to yield the title compound containing ~50% diglyme: bp: 55 / 1.2 mmHg, density @ 20°C: 0.827, FTIR: vS-H: 2140 (vs).

[0056] Those skilled in the art will appreciate that changes can be made to the above embodiments without departing from the broad inventive concept thereof. Therefore, it should be understood that the present invention is not limited to the particular embodiments disclosed, but is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.

Claims

1. A reaction product of a hydridosilazine pyrrole or a hydridosilazine pyrrole and a substrate having a hydroxyl group; in, The hydridosilicon pyrrole or hydridosilicon azapyrrole is a hydridosilicon pyrrole or hydridosilicon azapyrrole as shown in formula (I); in, Z1 is C or N, Z2 is H or R'; R is a hydrocarbyl group having up to six carbon atoms, a nitrogen-substituted hydrocarbyl group having up to six carbon atoms, or a trimethylsilyl group; and R' is an alkyl group having fewer than six carbon atoms; or, The hydridosilicon pyrrole or hydridosilicon azapyrrole is 2. A method for preparing hydridosilicon pyrrole or hydridosilicon azapyrrole; in, The hydridosilicon pyrrole or hydridosilicon azapyrrole is a hydridosilicon pyrrole or hydridosilicon azapyrrole as shown in formula (I); in, Z1 is C or N, Z2 is H or R'; R is a hydrocarbyl group having up to six carbon atoms, a nitrogen-substituted hydrocarbyl group having up to six carbon atoms, or a trimethylsilyl group; and R' is an alkyl group having fewer than six carbon atoms, Alternatively, the hydridosilicon pyrrole or hydridosilicon azapyrrole is The method includes reducing a cyclic azasilane having an alkoxy group on silicon.

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