JPH0341405B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing low-halogenated silane or monosilane from halogenated silane, and more specifically, by bringing halogenated silane into contact with a specific compound, low-halogenated silane or monosilane can be produced easily and inexpensively. Relating to a method of manufacturing.

In particular, monosilane is a useful material as a raw material for high-purity semiconductor silicon or amorphous silicon for solar cells, and as a raw material for epitaxial use, and demand is expected to further increase in the future.
Therefore, cheaper and more efficient monosilane production is desired.

Conventional methods for producing monosilane include (1) a method in which magnesium silicide is reacted with dilute hydrochloric acid, (2) a method in which tetrachlorosilane is reacted with LiH in a molten salt, and (3) a method in which hydrogen gas is applied to metallic silicon at high temperature and high pressure. A method is known in which the reaction is performed using Ni fine powder under the following conditions.

However, in the case of (1) above, the preparation of raw materials is complicated, and the equipment cost increases considering the reuse of by-product high-order silane. Method (2) has a good yield of monosilane, but LiH is extremely expensive, and since molten salt is used, there are problems in terms of energy consumption and corrosion. (3) is a reaction at high temperature and high pressure, so equipment costs are high;
It also has the disadvantage of producing high-order silane as a by-product.

On the other hand, a method (4) has been proposed in which trichlorosilane is subjected to a disproportionation reaction with an anion exchange resin containing a tertiary amino group or a quaternary ammonium base.
Although this method (4) has a problem with the thermal stability of the ion exchange resin, it is superior in terms of energy cost and mass production.

The present inventors have conducted intensive research on the disproportionation reaction corresponding to (4) above in order to produce monosilane inexpensively and efficiently with the main objective. As a result, the inventors discovered that a low halogenated silane or monosilane can be easily obtained by contacting a halogenated silane with a compound having an amino group and a phosphonic group, leading to the present invention.

The halogen silane that is the raw material of the present invention includes:
General formula SiHX ₃ , SiH ₂ X ₂ , SiH ₃ X (X: halogen)
For example, trichlorosilane, dichlorosilane, and monochlorosilane are applicable, but bromosilane, fluorosilane, and iodosilane can also be used. Therefore, according to the present invention, the above-mentioned halogensilane is reduced in halogenation, and SiHX ₃ is converted into SiH ₂ X ₂ , SiH ₃ X, SiH 3
SiH ₄ , _{SiH 3 X} , SiH ₄ from SiH ₂
Although SiH ₄ can be produced from SiH ₃ X depending on the purpose, SiH ₄ can be particularly preferably obtained from SiH ₂ X ₂ .

The compound having an ion exchange group such as an amino group or a phosphonic group used in the present invention is generally a liquid compound or a compound in which the ion exchange group is bonded directly or indirectly to a saturated or unsaturated alkyl group, phenyl group, or benzyl group, respectively. For example, it is an insoluble solid compound, generally an ion exchanger, bonded directly or indirectly to a crosslinkable polymer such as polystyrene or a styrene-divinylbenzene copolymer. The above amino group includes a primary amino group, a secondary amino group, a tertiary amino group, or a quaternary ammonium group, and the phosphonic group includes -PO ₃ H ₂ , -PO ₂ H ₂ , Including substitution types such as Na type.

According to the present invention, as shown in the examples below, the yield of the target low halogenated silane or monosilane is higher than when using a compound having only an amino group or a compound having only a phosphonic group. You can get a good deal.

The halogen silane, which is a raw material of the present invention, is generally used as a gas or liquid, and the compound is also used as a liquid or solid, so the reaction form is highly flexible and an advantageous form can be selected as necessary. Furthermore, an embodiment in which the liquid ion exchanger is supported on, for example, activated carbon, alumina, silica-alumina, etc., is also preferably employed in order to control the optimum amount of the ion exchanger.

Conditions such as the amount of compound used, reaction temperature, and contact time in the present invention cannot be determined unconditionally because they vary depending on the reaction form. The reaction temperature is generally 25~
A temperature of 350°C, particularly 50 to 120°C, is preferred from the viewpoint of reactivity and energy economy. Also, contact time is generally
0.1 to 60 seconds, especially 1 to 20 seconds is sufficient.

Separation of the desired low halogenated silane or monosilane from the reaction product obtained by the present invention,
Generally, this can be easily achieved under favorable conditions such as distillation by refluxing other reaction products appropriately using a cooler, etc., and by utilizing the boiling point difference between other reaction products, unreacted products, and polyamine compounds. can.

Examples will be shown below, but the present invention is not limited thereto.

Example 1 Chelate resin having ₂ -NH-CH2 _{- PO3H} groups
Duolite ES467 (manufactured by Diamond Shamlok)
Put 10g into a stainless steel reactor and set the temperature to 60℃.
I kept it. Next, add dichlorosilane to 0.8/mm
As a result of flowing at a flow rate of 25.3 mole% monosilane,
A product containing 18.9 mole% of monochlorosilane was obtained.

Example 2 Except that trichlorosilane was flowed at a flow rate of 0.5/mm instead of dichlorosilane in Example 1,
It was carried out in the same manner as in Example 1. As a result, monosilane 12.3 mole%, monochlorosilane 10.8 mole%,
A product containing 19.6 mole% of dichlorosilane was obtained.

Comparative Example 1 In place of Duolite ES467 in Example 1, the third
Ion exchange resin Amberliat with grade amino groups
The same procedure as in Example 1 was carried out except that A-21 (manufactured by Rohm and Haas) was used. As a result, monosilane 16.3 mole%, monochlorosilane 12.6 mole%
% product was obtained.

Claims (1)

[Claims] 1. A method for producing a low halogenated silane or monosilane, which comprises contacting a halogenated silane with a compound having an amino group and a phosphonic group.