JPH0328367B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention produces the general formula by reacting an alloy containing magnesium and silicon with an acid.
The present invention relates to a method for producing silicon hydride represented by SinH _2o+2 (n is a positive integer of 1 or more). More specifically, the present invention relates to a method for producing silicon hydride by reacting the silicon alloy with an acid in a solvent containing a chain or cyclic nitrogen-containing organic compound under conditions substantially free of water. In recent years, with the development of the electronics industry, the demand for silicon for semiconductors such as polycrystalline silicon or amorphous silicon has increased rapidly.
Silicon hydride, SinH _2o+2 , has recently become more important as a raw material for manufacturing silicon for semiconductors, and in particular, silane (SiH ₄ ) and disilane (Si ₂ H ₆ ) are used as raw materials for semiconductors for solar cells, etc. Demand is expected to increase significantly in the future. Conventionally, the following methods have been known as main methods for producing silicon hydride. A method of reacting a silicon alloy with an acid in an aqueous solution, for example, Mg ₂ Si + 4HClaq → 2MgCl ₂ + 1/n
SinH _2o+2 + (1-1/n) H ₂ A method of reacting a silicon alloy with an acid in liquid ammonium, for example, Mg ₂ Si + 4NH ₄ Br→
2MgBr ₂ +4NH ₃ +1/nSinH _2o+2 +(1-1/n)
A method of reacting H ₂ silicon halide with a reducing agent in an organic solvent, e.g. SiCl ₄ + LiAlH ₄ → LiCl
+AlCl ₃ +SiH _4Method by averaging silicon hydrides containing halogens, e.g. Si+SiCl ₄ +2H ₂ →SiHCl ₃ +
SiH ₃ Cl 2SiHCl ₃ →SiCl ₄ +SiH ₂ Cl ₂ 2SiH ₂ Cl ₂ →SiH ₃ Cl＋SiHCl ₃ 2SiH ₃ Cl→SiH ₄ +SiH ₂ Cl _2The above method can carry out the reaction at approximately room temperature and pressure, but various As silicon hydride and semiconductor gases, oxygen-containing silicon compounds (such as silyl ether), which have many problems in use, are generated as impurities, and their separation is difficult, and silicon hydride, SinH _2o+2, is difficult to separate. There are fatal problems such as low conversion rate. In the method, the reaction is carried out in liquid ammonia, so when carried out under normal pressure,
It is difficult to carry out industrially because it is necessary to control the internal temperature using a refrigerant that is below the boiling point of ammonia. Further, the method includes problems such as that the reducing agent is expensive, and that the method requires reaction control at high temperature and high pressure. The present inventors have made earnest efforts to develop a new manufacturing method in order to solve the problems of these conventional methods, and as a result, have arrived at the present invention. That is, the present invention is based on the general formula

【formula】

[Formula] R ₈ =N- R ₉ ,

[Formula] or

[Formula] (wherein R ₁ to R ₁₂ are hydrocarbon groups or hydrogen, and at least one R in the same molecule is a hydrocarbon group) Hydrogen characterized by using at least one type of nitrogen-containing organic compound as a solvent, and reacting an alloy containing magnesium and silicon with an acid in the presence of the solvent under substantially water-free conditions. This is a method for producing silicon oxide. According to the present invention, it is possible to produce high-purity silicon hydride that does not contain impurities such as oxygen-containing silicon compounds at low cost. The present invention will be explained in detail below. The silicon alloy used in the present invention has silicon and magnesium as essential components, and may also contain a third component metal. The atomic ratio of magnesium and silicon (Mg/Si) is 1/3
It is desirable that it be in the range of ~3/1. Specific examples include Mg ₂ Si, Mg ₂ SiNi, Mg ₂ SiAl,
Mg ₂ Si ₂ Ba, MgSiBa, CeMg ₂ Si ₂ , Mg ₆ Si ₄ Cu ₁₆ ,
Examples include Mg ₃ Si ₆ Al ₈ Fe. These can also be used as a mixture of two or more. Further, the grain size of the alloy is not particularly limited, but the finer the grain size, the better. However, for economical or handling reasons, a range of 20 to 300 meshes is desirable. Next, the chain or cyclic nitrogen-containing organic compound used as a solvent has the general formula

【formula】

[Formula] R ₈ = NR ₉ ,

【formula】 or

[Formula] (In the formula, R ₁ to R ₁₂ are hydrocarbon groups or hydrogen, and R in the same molecule
(at least one of which is a hydrocarbon group) and is substantially anhydrous. Specific examples of such nitrogen-containing organic compounds include methylamine, ethylamine, propylamine, hexylamine, dimethylamine, diethylamine,
Di-n-butylamine, trimethylamine, triethylamine, N-methylethylamine, N-methylbutylamine, N-ethyl-N-methylpropylamine, ethylenediamine, trimethylenediamine, 1,2,3-triaminopropane, diethylenetriamine, piperidine, allylamine , isopropanolamine, methyldi(2-chloroethyl)amine, aniline, anisidine, 2-ethyl-P-phenylenediamine, naphthylamine,
Preferred examples include pyridine. Among these, those having a boiling point in the range of 0 to 200°C are particularly desirable from the viewpoint of yield of silicon hydride and control of reaction temperature. Incidentally, two or more of these can be used as a mixed solvent, and solvents other than the nitrogen-containing organic compounds, such as ethers, hydrocarbons, halogenated hydrocarbons, etc., can also be used in combination. In the present invention, the nitrogen-containing compound is used under substantially anhydrous conditions, but the dehydration method is not particularly limited, and any commonly used method can be employed. The water content is
It is desirable that the content be 1000 ppm or less, preferably 100 ppm or less. For example, sodium, potassium,
Calcium chloride, sodium sulfate, phosphorus pentoxide,
Treatment with a dehydrating agent or adsorbent such as a molecular sieve is sufficient to achieve the objective. Examples of acids include inorganic acids such as hydrogen chloride, hydrogen bromide, hydrogen fluoride, sulfuric acid, and phosphoric acid, and organic acids such as acetic acid, formic acid, and propionic acid, which are left in a substantially anhydrous state after dehydration. used in Among these, hydrogen chloride and sulfuric acid are preferred in view of the yield of silicon hydride. Next, the mode of reaction will be described. The present invention involves reacting a silicon alloy with an acid in a nitrogen-containing organic solvent in a substantially anhydrous state, and there are no particular limitations on the method of charging each of these reaction components. For example, a silicon alloy and an acid are charged simultaneously into a nitrogen-containing organic solvent, a silicon alloy is charged into a nitrogen-containing organic solvent in which an acid has been dissolved, or an acid is charged into a suspension of a silicon alloy. Various reaction modes can be adopted, such as adding The amount balance of the nitrogen-containing organic solvent, acid, and silicon alloy can be changed depending on the reaction mode and the type of nitrogen-containing organic solvent, but in terms of the yield of silicon hydride, the amount of acid used is determined by the amount of the silicon alloy. It is necessary that the amount is at least the reaction equivalent. The reaction temperature is -25 to 300°C, preferably from room temperature to the boiling point of the nitrogen-containing organic solvent. Further, the reaction is usually carried out under normal pressure or increased pressure, but it can also be carried out under reduced pressure. Although the atmospheric gas is not necessarily required, for example, nitrogen, hydrogen, helium, argon, etc., which do not react with the silicon hydride produced, may be used if necessary. Although there are no restrictions on the formation of the reactor, it is desirable that the reactor be capable of grinding the contents by stirring to some extent in order to remove by-product magnesium salts formed on the surface of the silicon alloy. Separation and purification of the produced gas can be carried out by conventional cryogenic separation, adsorbent, etc., respectively. According to the present invention, it is possible to select a reaction temperature that does not require a low-temperature refrigerant under normal pressure or under increased pressure. In addition, the conversion rate of silicon in silicon alloys to silicon hydride, SinH _2o+2, is high, so silicon hydride, especially silane (SiH ₄ ), can be used at low cost.
It is possible to manufacture Furthermore, the silicon hydride obtained by the present invention contains few impurities such as oxygen-containing silicon compounds, and silicon hydride of sufficiently high purity can be obtained without going through complicated purification steps. Hereinafter, the present invention will be explained with reference to Examples. Example 1 A separable flask with a capacity of 500 ml was charged with 200 ml of aniline dehydrated with Molecular Sib-3A, and the temperature of the aniline was brought to 150°C.
Hydrogen chloride gas dehydrated with phosphorus pentoxide was blown into this. The amounts of hydrogen chloride and water contained in the aniline were 10 wt.% and 5 wt.ppm, respectively.
Next, in a hydrogen gas atmosphere, about 100 ml of glass beads (diameter 3 mm) was added to this aniline solution, and while grinding and stirring, 6.0 g of magnesium silicide (Mg ₂ Si) (particle size 100 to 200 mesh,
78.2 mmol-Si) was continued to be added at a constant rate for 40 minutes.
During this time, the reaction temperature was maintained at 150°C by heating the liquid with a heating medium. The generated gas is collected in a trap cooled at the temperature of liquid nitrogen, and after the reaction is completed (after the magnesium silicide injection is completed), the gas in the collected gas is
The amounts of SiH ₄ , Si ₂ H ₆ , and Si ₃ H ₈ were analyzed and quantified by gas chromatography. Furthermore, the amount of SiH ₄ , Si ₂ H ₆ , and Si ₃ H ₈ dissolved in the reaction solution was also determined by gas chromatography. The amounts of SiH ₄ , Si ₂ H ₆ , and Si ₃ H ₈ produced are
They were 45.1 mmol, 3.8 mmol, and 0.5 mmol. The amounts of these three types of silicon hydrides correspond to 69.3% of the silicon in the magnesium silicide subjected to the reaction. The gas obtained in the cylinder was also measured using a gas chromatograph mass spectrometer, but no compound having a silyl ether bond (Si--O--Si bond) was detected. Examples 2 to 6 Experiments were conducted in the same manner as in Example 1, except that ethylenediamine, n-propylamine, hexylamine, pyridine, and anisidine were used instead of aniline. The results are shown in Table 1. <Comparative Example> An experiment was conducted in the same manner as in Example 1 except that aniline with a water content of 5 wt.% was used. The results are shown in Table 1. In addition, when the collected gas in the cylinder was measured using a gas chromatograph mass spectrometer in the same manner as in Example 1,
Plural peaks of compounds corresponding to silyl ether bonds (Si-O-Si) were observed, and it was inferred from these that a considerable amount of compounds having silyl ether bonds were produced as by-products.

【table】

Claims (1)

[Claims] 1 General formula [Formula] [Formula] R ₈ =N-R ₉ , [Formula] or [Formula] (In the formula, R ₁ to R ₁₂ are hydrocarbon groups or hydrogen, and are the same At least one type of chain or cyclic nitrogen-containing organic compound selected from the group represented by (at least one R in the molecule is a hydrocarbon group) is used as a solvent, and magnesium is dissolved in the presence of the solvent. and the general formula SinH _2o+2 (n is a positive integer of 1 or more) characterized by reacting an alloy containing silicon with an acid under substantially water-free conditions.
A method for producing silicon hydride represented by 2. The method according to claim 1, wherein the alloy containing magnesium and silicon is magnesium silicide. 3. The method according to claim 1, wherein the acid is hydrohalic acid, sulfuric acid, phosphoric acid, or an organic acid.