JPS6153109A - Production of silicon hydride - Google Patents

Abstract

PURPOSE:To convert various silicon compounds produced as by-products to a silicon hydride having high commercial value, in high yield, by reacting a specific silicon compound with an alkyl aluminum halide. CONSTITUTION:The silicon hydride of formula II (l<x) is produced by contacting the silicon compound of formula I (x>=1; at least one of y and z is not 0; when x=1, z is not 0) with an alkyl aluminum halide. The compound of formula I is preferably the one having at least one Si-H bond or Si-Si bond in the molecule, e.g. disilane (Si2H6), trisilane (Si3H8), cyclohexasilane (Si6H12), etc. The amount of alkyl aluminum halide is about 0.001-100mol per 1mol of Si in the silicon compound used as the raw material.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to the general formula SixHyOz (where X is a positive integer of 1 or more, y and 2 are each 2) (a positive integer not exceeding +2.2X, and either relates to a method for producing silicon hydride represented by the general formula S + 21 + 2 (l is a positive integer smaller than X) from a silicon compound represented by .

[Background technology]

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 has recently become more important as a raw material for manufacturing silicon for semiconductors, and in particular, silane (Si) and disilane (5i2Ha)
) is expected to see a significant increase in demand in the future as a raw material for solar cell pickles.

Several methods for producing silicon hydride have been known, among which a method for producing silicon hydride by reacting magnesium silicide with an acid has been known for a long time as a particularly easy and economical method.

2MgC12+ ]/n5inH2n+, + (1-
1/n)H2However, in this method, a considerable amount of higher silane other than 5iI-I4.5i2I(6), which has high utility value, is produced.For example, when water is used as a solvent, Although the reaction can be carried out at normal pressure, about half of the Si in Mg25L is 5ipHqOr (p is a positive integer of 3 or more, q and r are each positive integers not exceeding 2p + 2.2p, and one of them is not O). ), which is not economically viable.

In addition, it is known that higher silane is produced as a by-product even when silicon hydride is produced by reducing a silicon halide; for example, when 512H6 is produced by the reaction of
Significant amounts of higher silanes such as Si3H8 are produced.

On the other hand, it has been reported that high-grade silane SirrH2m+2 (m is a positive integer of 2 or more) can be partially converted into SiH, Si2H6, etc. by thermal decomposition or silent discharge, but the conversion rate to SiH4, Si2H6 is is still low and insufficient.

In view of the above points, the present inventors have made extensive studies and found that most of the various silicon compounds produced as by-products in conventional methods are expressed by the general formula S i x Hyoz, and that reaction treatment with specific substances is necessary. It has been found that the desired silicon hydride such as SiH, 5i2H0, etc. can be converted in high yield by applying this method.

[Purpose of the invention]

An object of the present invention is to provide a method for converting various silicon compounds produced as by-products in the conventional methods described above into economically valuable silicon hydrides such as SiH4 and Si2H6 in high yield. That's true.

[Disclosure of the invention]

According to the present invention, the general formula 5ixE(yoz (where X is a positive integer of 1 or more, y and 2 are each 2x+2.2
By contacting an alkylaluminum hydride with a silicon compound represented by a positive integer not exceeding x, one of which is not O, and when x=1, 2 is not 0), a silicon compound of the general formula 5iIIIH2, 6, (wherein is a positive integer smaller than X) a method for producing silicon hydride is provided.

The present invention will be explained in detail below.

The silicon compound used as a raw material in the method of the present invention has the general formula S i xI(yOZ (where X is 1
Positive integers greater than or equal to y and 2 are each 2X+2.2X
(a positive integer not exceeding , one of which is not O)
It contains a small amount of trisilane (S) in the molecule.
"sHs), n-tetrasilane (Si4H10) isotetrasilane (5i4H+o), cyclohexadi,
U7 (Si, I(,2), polysilene ((SiI-I
Jn), Disilokki f7 (5i2I(,O),)
! J'10ki f7 (Si, H802), tetrasiloxane (Si, H, oOl), siloxene ((S
i2I(20)n), etc. It is also possible to use a mixture of two or more of these or a mixture thereof. Furthermore, as described below, these can be used dissolved or suspended in aliphatic saturated hydrocarbons, aromatic hydrocarbons, diluents such as ether, or organic solvents, and can be used in any of the gas, liquid, and solid phases. It can also be used in

It is also a compound having the reducing ability shown by alkyl aluminum hydride R31AiH2 used in the method of the present invention.

Here, R1, R, and R are both alkyl groups having 1 to 10 carbon atoms. Examples thereof include ethyl group, n-propyl group, isobutyl group, n-hexyl group, and n-octyl group. R1 and horse may be the same or different. Among the compounds represented by the above general formula, preferred examples include dimethylaluminum rhamnohydride, diethylaluminum nohydride, diimprobil aluminum rhamnohydride, diimptylaluminohydride
hydride, di-2-methylbutylaluminum nohydride, and ethylaluminum dinohydride. It is also possible to use two or more of these in combination, and it is preferable to use them after diluting them to a desired concentration with an organic solvent as described below. The proportion of these alkyl aluminum hydrides to be used is not particularly limited, but is generally in the range of 0.001 to 100 times the mole of silicon in the raw material silicon compound.

Next, a method of contacting a silicon compound and an alkyl aluminum hydride in the present invention will be described. Basically, it can be carried out in any of the gas phase, liquid phase, and solid phase methods, and as the easiest method to implement, for example, the following method can be adopted.

(1) A silicon compound and an alkyl aluminum hydride are dissolved in a solvent and brought into a contact reaction in a liquid phase.

(2) A gaseous silicon compound is brought into contact with an alkyl aluminum hydride dissolved in a solvent.

Of course, the present invention is not limited to these methods. The solvent used here is preferably one that has excellent solubility in the silicon compound and does not react with the alkyl aluminum hydride, such as aliphatic saturated hydrocarbons, alicyclic saturated hydrocarbons, aromatic hydrocarbons, ethers, etc. can be given. More specifically, pentane, heptane, octane, nonane, cyclohexane,
Examples include liquid halafine, benzene, toluene, xylene, diethyl ether, dibutyl ether, diethylene glycol dimethyl ether, tetrahydrofuran, and dioxane. These can be used in combination of two or more kinds, and it is desirable to perform sufficient dehydration.

There is no particular restriction on the reaction temperature, but if it is too low, the reaction will be slow, and if it is too high, the alkyl aluminum will self-decompose and side reactions will occur. Preferably, the range of 0 to 50°C is used.Also, the reaction time varies depending on the reaction mode, but is preferably 1 minute to 48 hours.Reaction pressure ◇ is normal pressure to 2 ky/
cnt (gauge pressure) is sufficient, but it may also be carried out under reduced or increased pressure depending on the reaction temperature or equipment.The raw materials and products used in this reaction are active and react particularly with oxygen and moisture. Since most of the substances decompose or ignite, the reaction must be carried out in an atmosphere that is inert to the raw materials used and the products produced. The reaction must be carried out under an active gas, nitrogen, or hydrogen atmosphere.This reaction can be carried out in any batch, semi-batch, or continuous manner.

[Preferred Mode for Carrying Out the Invention] The present invention will now be described in more detail with reference to Examples.

Example 1 In a separable flask with a volume of t 4 II, 120 wt of concentrated
% hydrochloric acid aqueous solution 21. Charge 1 volume of diethyl ether 300I. In a hydrogen gas atmosphere, under conditions where the above mixture is refluxing (reaction temperature 35°C), magnesium silicide 6 is further added.
09 (particle size 100 to 200 mesh, 782 rr
mol -8i) li over 200 minutes while stirring,
The addition was continued at a constant rate of 0.3, jil/min.

After the reaction is completed (after the addition of magnesium silicide), the reaction solution is cooled to 0°C, left to stand, and a diethyl ether layer of approximately 0.4
4 was isolated. The acidic aqueous solution in the reactor was heated to 80°C, and a small amount of dissolved diethyl ether was expelled.
This was mixed with the diethyl ether layer separated into two layers. During the reaction, the gas generated during the two-layer separation and heating treatment of the acidic aqueous solution is first transferred to a trap (trap (■)) containing diethyl ether cooled to -70°C, and then transferred to a trap containing diethyl ether cooled to -70°C. Trap cooled by (Trap (ID)
It was collected at.

Next, the diethyl ether layer after two-layer separation and the trap (
The mixture of ethers in 1) is distilled in a distillation column with about 3 plates, and 5i2H,,5i2)( is distilled and separated to obtain SiH, (bp-112℃), S1□Ha(bp- 1
A trap (II
) was added and collected. Si) [, Si2H6,
The amount of 5i3f(i8i, H, o) was analyzed and quantified by gas chromatography.

The amounts of silanes in trap (II) and diethyl ether layer were as shown below.

Further, colorimetric analysis of the amount of Sl in the diethyl ether layer revealed that the content was 324 mmol. In addition, the 1-pack spectrum revealed that the silicon compound contained Si-8g bonds, 5i
In addition to -H bonds, it was recognized that a considerable amount of Si-〇-8i bonds existed. Diethyl ether was further added to this to obtain 0.5 g of diethyl ether solution (1). The concentration of 81 in this solution (I) is 0.649rrmol Si
atm/mlsop, ma7-, :5i3H6, Si,
H. The concentration of each is 0.030 mmol/
ml so8″n, 0.021rrrno 17ml
It was so 1m.

Next, add this ether solution (1) to Molecuira Sheep-34
By dehydrating at 55.9, it becomes 810 degrees 0.6
A diethyl ether solution (It) of 49 mmol Si atm/mlso1m was obtained. 513) in this solution
(8,514f (lo concentration is 0.035mm each)
ol/ml so#m, 0.02 Drrmol
/ml solm-1 The water content is 21) I) m.

A hexane solution of diethylaluminum hydride (concentrated! 5.9rr mol /
After that, a diethyl ether solution (ID 1o + g7) containing the above silicon compound was added, and the reaction was carried out at room temperature.The reaction was carried out with stirring, and the atmosphere gas was hydrogen, and the reaction was carried out at room temperature. The gas was collected in a trap cooled at liquid nitrogen temperature. After 1 hour, the reaction was terminated, and the amount of collected 5i)(, 5i2)(6) was analyzed and quantified by gas chromatography.

The amount of SiH,, Si2H,, is 2-Q
9 rrmol, 0,97 rrmol lj, which is the 62% of silicon in diethyl ether used as the reaction solution.
．． 1% of priests.

Furthermore, the generation ratio of SiH and S1□ bars was (8iH,/Si, H6 = 1.08) based on silicon atoms.

Examples 2 to 4 Table 1 (Effects of the invention and industrial applicability 9)
The present invention can be carried out by various methods, for example, Sin, , 5i2H
By contacting a part of the silicon compound represented by the general formula SixHg0z, which is a by-product when producing silicon hydride such as
, Si2H6, etc., and it must be said that its industrial applicability is extremely high. It goes without saying that by applying the method of the present invention to a conventional manufacturing process of silicon hydride such as 8iH, 5ixp, etc., the economic efficiency of the process itself is greatly improved.

Claims (4)

[Claims] (1) General formula Si_xH_yO_z (where x is a positive integer of 1 or more, and either one is not 0 and x = 1
A method for producing silicon hydride represented by the general formula Si_lH_2_l_+_2 (where l is a positive integer smaller than x) by contacting a silicon compound represented by (where z is not 0) with an alkyl aluminum hydride. . (2) Silicon compound (Si_xH_yO_z) has the general formula Si_xH_2_x_+_2 (x is a positive integer of 2 or more)
The method according to claim (1), which is represented by: (3) The method according to claim (1), wherein the silicon hydride (Si_lH_2_l_+_2) is SiH_4 or Si_2H_6. (4) The method according to claim (1), wherein the silicon compound is dissolved in an organic solvent.