KR20060093391A - Silicon(iv) complexes of aminoalkoxide and preparation method thereof - Google Patents

Abstract

The present invention relates to a silicon compound represented by the following formula (1) and a method for producing the same, the new silicon compound according to the present invention is thermally stable, stable in the air, the volatility is improved to produce a high quality silicon or silicon oxide thin film It can be used to advantage.

[Formula 1]

Si (OCR ¹ R ² CH ₂ NR ³ ₂ ) ₄

Wherein R ¹ , R ² and R ³ are C ₁ -C ₄ linear or branched alkyl.

Silicone compound

Description

SILICON (IV) COMPLEXES OF AMINOALKOXIDE AND PREPARATION METHOD THEREOF

1 is a hydrogen atom nuclear magnetic resonance ( ¹ H NMR) spectrum of Si (dmamp) ₄ prepared in Example 1 according to the present invention,

2 is a carbon atom nuclear magnetic resonance ( ¹³ C NMR) spectrum of Si (dmamp) ₄ prepared in Example 1 according to the present invention,

3 is a result of Fourier transform infrared spectroscopy (FTIR) analysis of Si (dmamp) ₄ prepared in Example 1 according to the present invention,

4 is a graph showing the results of thermogravimetric analysis (TGA) and differential thermal analysis (DTA) of Si (dmamp) ₄ prepared in Example 1 according to the present invention.

FIELD OF THE INVENTION The present invention relates to novel silicone compounds, and to methods of preparing compounds useful as precursors of silicon or silicon oxide thin films.

Silicon oxide has been widely used as an insulator because of its stable and high quality silicon-silicon oxide interface and excellent electrical insulation properties. Recently, polycrystalline silicon thin films are used for thin film transistors (TFT), solar cells, and the like.

The metal organic chemical vapor deposition (MOCVD) process, which is used in the manufacture of various oxide thin films in the thin film manufacturing technology, is relatively simple in equipment, uniform in layer covering, easy to control ingredients, and difficult to convert to mass production. There is no advantage.

In order to manufacture a thin film using such a MOCVD process, it is essential to develop a precursor material used in this process and to understand its characteristics. The precursors for MOCVD must have a sufficiently high vapor pressure below 200 ° C, be thermally stable enough for heating to vaporize, and decompose rapidly at the substrate temperature of 350 to 500 ° C without decomposition of organic materials, etc. Should be stable enough to air and moisture while. In addition, it should be non-toxic or less toxic to the precursor itself or to the decomposition products, the synthesis method should be simple and the raw material cost should be low.

The precursors that have been used to make silicon compounds into thin films are classified into four types, and include silanes, silane chlorides, alkoxide compounds, and compounds including β -diketonate.

Silane is a gas at room temperature, stable to high pressures and impacts, but burns or explodes when mixed with oxygen. It should also be handled with care as it reacts with moisture to form powder or particles. SiCl ₄ is a precursor of atomic layer deposition (ALD) with H ₂ O, which can produce silicon oxide thin films at reactant pressures of 1-10 Torr and temperatures of 600-800 K (JW Klaus, AW Ott, JM Johnson, and SM George, Appl. Phys. Lett. 1997 , 70 , 1092). Like silanes, it can react sensitively to moisture and contaminate the surface with chlorides during the manufacture of thin films.

SiH ₂ Cl ₂ has also been used to produce silicon oxide thin films at 300 ° C using atomic layer deposition with O ₂ or O ₃ ( Japanese Journal of Applied Physics, Part 2: Letters & Express Letters 2004 , 43 (3A ) , L328-L33).

Among the compounds containing alkoxides, tetraethylorthosilicate (TEOS), which is most commonly used as a precursor of silicon oxide thin films, is liquid at room temperature and is easy to handle, but it is difficult to react with water and hydrolyze into SiO ₂ and ethanol. slow. The precursor material was deposited by a low-pressure chemical vapor deposition (LPCVD) or atmospheric pressure chemical vapor deposition (APCVD) at a temperature of about 400-900 ° C. (J. Crowell, L. Tedder, H. Cho, F. Cascarano and M. Logan, J. Vac. Sci. Technol.A 1990 , 8 , 1864; L. Tedder, G. Lu and J. Crowell, J. Appl. Phys. 1991 , 69 , 7037; M. Islam Raja , C. Chang, J. McVittie, M. Cappelli and K. Saraswat, J. Vac. Sci. Technol.B 1993 , 11 , 720; D. Williams and E. Dein, J. Electrochem.Soc. 1988 , 134 , 657).

Compounds containing β -diketonate include SiClMe (acac) ₂ , SiClPh (acac) ₂ , SiMe ₂ (acac) ₂ (acac = acetylacetonate), but are very unstable and have low yields. Si (OAc) ₂ (acac) ₂ and SiX ₂ (thd) ₂ (X = Me, O ^t Bu, O ^t Am, thd = 2,2,6,6-tetramethyl-3,5-heptanedione) are more Although stable, compounds containing β -diketonate have the disadvantage of high deposition temperature during the MOCVD process due to high thermal stability (C. Xu, TH Baum, AL Rheingold, Inorg. Chem. 2004 , 43 , 1568; R. West, J. Am. Chem. Soc. 1958 , 80 , 3246; RM Pike and RR Luongo, J. Am. Chem. Soc. 1966 , 88 , 2972; DW Thompson, Inorg.Chem. 1969 , 8 , 2015; KM Taba and WJ Dahlhoff, J. Organomet. Chem. 1985 , 280 , 27).

In order to solve the problems of the compounds, the present inventors introduced a new ligand to coordinate the dialkylamino group in the silicon so as not to cause contamination of carbon or halogen, and a new silicon or silicon oxide precursor having improved thermal stability and volatility. Led to develop.

It is an object of the present invention to provide a silicon compound precursor that is thermally stable and has increased volatility to form high quality silicon or silicon oxide thin films.

In order to achieve the above object, the present invention provides a new silicon compound precursor represented by the following formula (1).

[Formula 1]

Si (OCR ¹ R ² CH ₂ NR ³ ₂ ) ₄

Where

Independently R ¹ , R ² and R ³ are C ₁ -C ₄ linear or branched alkyl, preferably CH ₃ , C ₂ H ₅ or CH (CH ₃ ) ₂ .

Hereinafter, the present invention will be described in more detail.

The compound represented by Chemical Formula 1 according to the present invention may be prepared by performing a substitution reaction in an organic solvent with an alkali metal salt of an amino alcohol represented by Chemical Formula 2 and a silicone compound represented by Chemical Formula 2 as a starting material:

[Formula 2]

SiCl ₄

[Formula 3]

MOCR ¹ R ² CH ₂ NR ³ ₂

Where

R ¹ , R ² and R ³ are as described above. M is an alkali metal selected from Li, Na and K.

In order to manufacture the silicon aminoalkoxide compound {Si (OCR ¹ R ² CH ₂ NR ³ ₂ ) ₄ } of the present invention, the compound of formula 3 using the compound SiCl ₄ represented by Formula 2 as a starting material {MOCR ¹ R ² Reaction with CH ₂ NR ³ ₂ } may be represented by the following Scheme 1.

Scheme 1

SiCl ₄ + 4 MOCR ¹ R ² CH ₂ NR ³ ₂ → Si (OCR ¹ R ² CH ₂ NR ³ ₂ ) ₄ + 4 MCl

Specifically, the compound of Formula 1 according to the present invention is dissolved in 1 equivalent of Compound 2 and 4 equivalent of Compound 3 in an organic solvent such as tetrahydrofuran, followed by a substitution reaction at room temperature for about 12 hours, and filtered under reduced pressure. It can be obtained by removing the solvent from the resulting filtrate under reduced pressure.

The starting material used in the reaction, the compound of formula 2, SiCl _4, contains halogen ions, and reacts with the compound of formula 3, which is an alkali metal salt, MOCR ¹ R ² CH ₂ NR ³ ₂ , which is a compound of formula 1, Si (OCR ¹ R ² CH ₂ NR ³ ₂ ) ₄ and 4 equivalents of MCl were produced.

Compound {Si (OCR ¹ R ² CH ₂ NR ³ ₂ ) ₄ }, which is a precursor of the novel silicon or silicon oxide thin film represented by Chemical Formula 1, is a stable chelate compound, and α- with respect to the oxygen of the alkoxide which is bonded to the metal. Non-polar alkyl groups bonded to the carbon position have high affinity for organic solvents, and the central metal bound to the oxygen of the alkoxide may exist as a monomer because it blocks steric hindrance to prevent intermolecular interactions with oxygen and nitrogen of neighboring ligands. . Due to such structural properties, the silicone compound represented by Chemical Formula 1 is a stable liquid at room temperature, has high solubility in organic solvents such as pentane, hexane, diethyl ether, tetrahydrofuran, toluene, etc., and has excellent volatility. It does not contain halogen elements, is stable at room temperature, and is stable in air, which is advantageous for storage, and these can be used to obtain better silicon or silicon oxide thin films.

The silicon aminoalkoxide compound of the present invention is a precursor for producing a silicon or silicon oxide thin film, and can be preferably applied to metal organic chemical vapor deposition (MOCVD) or atomic layer deposition (ALD) processes, which are widely used in semiconductor manufacturing processes.

The invention can be better understood by the following examples, which are intended for purposes of illustration of the invention and are not intended to limit the scope of protection defined by the appended claims.

All experiments were performed in an inert argon or nitrogen atmosphere using a glove box or Schlenk line. The structures of the reaction products obtained in Example 1 were respectively determined by ¹ H nuclear magnetic resonance (NMR), carbon atom nuclear magnetic resonance ( ¹³ C NMR), Fourier transform infrared spectroscopy (FTIR) analysis and elemental analysis. (elemental analysis, EA), thermogravimetric analysis / differential thermal analysis (TGA / DTA).

Preparation of Silicone Amino Alkoxide Compounds

Example 1

Tetra (1-dimethylamino-2-methyl-2-propoxy) silicon (IV) [Si (dmamp) ₄ Synthesis

In a 250 mL Schlenk flask containing tetrahydrofuran (150 mL), Nadmamp (sodium 1-dimethylamino-2-methyl-2-propoxide, 1-dimethylamino-2-methyl-2-propoxy sodium) , 13.0 g, 93.4 mmol) was dissolved and maintained at 0 ° C., and then SiCl ₄ (3.70 g, 21.8 mmol) was slowly added thereto and stirred at room temperature for 12 hours. The solution was then filtered to remove the solvent under reduced pressure to give the title compound (9.3 g) as a colorless liquid (yield: 86.6%).

¹ H NMR (C ₆ D ₆ , 300.13 MHz): δ 2.42 (s, 2 HC H ₂ N), 2.31 (s, 6 H, CH ₂ N (C H ₃ ) ₂ ), 1.54 (s, 6 H, C (C H ₃ ) ₂ ).

¹³ C NMR (C ₆ D ₆ , 75.04 MHz): δ 27.95, 48.56, 71.64, 76.76

Elemental Analysis C ₂₀ H ₄₆ N ₂ O ₄ Si {Calcd. (found)}: C, 58.49 (58.27); H, 11.45 (12.34); N, 11.37 (12.21).

The thermogravimetric analysis (TGA) and differential thermal analysis (DTA) of the silicon aminoalkoxide compound synthesized in Example 1 are shown in FIG. 4. From FIG. 4, it can be seen that Si (dmamp) ₄ rapidly volatilized near 165 ° C., and volatilization was completed near 275 ° C., leaving a residual of 14.22%.

As mentioned above, the silicon aminoalkoxide compounds of the present invention are less sensitive to moisture and advantageous in storage, and are particularly used in metal organic chemical vapor deposition (MOCVD) or atomic layer deposition (ALD), which requires good quality of oxide films. As a precursor of, there is no inferiority, and thus it can be usefully used as a precursor for producing an oxide thin film containing silicon.

Claims (6)

Silicone compound represented by the following formula (1). [Formula 1] Si (OCR ¹ R ² CH ₂ NR ³ ₂ ) ₄ Wherein R ¹ , R ² and R ³ are independently C ₁ -C ₄ linear or branched alkyl. The method of claim 1, Wherein R ¹ , R ² and R ³ are independently CH ₃ , C ₂ H ₅ or CH (CH ₃ ) ₂ . A method for preparing a silicone compound of formula 1 according to claim 1 comprising reacting a silicone compound represented by formula 2 with an alkali metal salt represented by formula 3 below. [Formula 2] SiCl ₄ [Formula 3] MOCR ¹ R ² CH ₂ NR ³ ₂ (Wherein R ¹ , R ² and R ³ are as defined in claim 1 and M is an alkali metal selected from Li, Na and K.) The method of claim 3, wherein Method for producing a silicone compound, characterized in that the dissolved in a polar solvent in the equivalence ratio of the compound of formulas (2) and (3) to perform a substitution reaction at room temperature. A method of growing silicon or silicon oxide by volatilization at high temperature using the silicon compound according to claim 1. 5. The method of claim 4, wherein the silicon or silicon oxide is formed by metal organic chemical vapor deposition or atomic layer deposition.

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