In order to produce high-purity trichlorosilane by removing methyldichlorosilane from a mixture (S) containing methyldichlorosilane (CH.sub.3HSiCl.sub.2), tetrachlorosilane (SiCl.sub.4), and trichlorosilane (HSiCl.sub.3) in the method for producing trichlorosilane of the present invention, a procedure is employed in which chlorine atoms are redistributed between methyldichlorosilane and tetrachlorosilane through catalytic treatment for conversion into trichlorosilane and methyltrichlorosilane (CH.sub.3SiCl.sub.3). Methyldichlorosilane (boiling point: 41° C.) having a boiling point close to that of trichlorosilane (boiling point: 32° C.) to be purified is converted into methyltrichlorosilane (boiling point: 66° C.) having a higher boiling point through redistribution of chlorine atoms between methyldichlorosilane and tetrachlorosilane, achieving easy removal of impurities.

The invention relates to a process and an apparatus for controlled preparation of octachlorotrisilane from monomeric chlorosilanes, by subjecting the chlorosilanes to a thermal plasma.

When a disproportionated chlorosilane is to be produced by causing a starting material chlorosilane liquid to flow through a catalyst-packed layer which is packed with a weakly basic anion exchange resin as a disproportionation reaction catalyst to carry out a disproportionation reaction, before the disproportionation reaction is carried out, the disproportionation reaction catalyst is brought into contact with a processing gas obtained by diluting a chlorosilane with an inert gas to prevent the deterioration of the disproportionation reaction catalyst at the start of the reaction so as to carry out the disproportionation of the chlorosilane efficiently.

The present invention relates to a process for preparing chlorinated oligosilanes, wherein chlorinated polysilane having an empirical formula of SiCl.sub.1.0-2.8 and/or a mixture comprising the chlorinated polysilane is reacted with elemental chlorine or a chlorine-containing mixture. Additionally claimed are chlorinated oligosilanes prepared by the process and the use thereof for production of semiconductors and/or hard coatings.

By incorporating an additional TCS and/or DCS redistribution reactor in the TCS recycle loop and/or DCS recycle loop, respectively, of a process and system for silane manufacture, efficiencies in the production of silane are realized. Further improvements in efficiencies may be realized by directing a portion of the product from a redistribution reactor into a distillation column, and specifically into the distillation column that formed the feedstock that went into the redistribution reactor.

1. The present invention relates to a method for the purification of halogenated oligosilanes as a pure compound or mixture of compounds each having at least one direct Si—Si bond, the substituents thereof being exclusively halogen or halogen and hydrogen, and the composition thereof being an atom ratio of substituent:silicon of at least 3:2, by the action of at least one purification agent on the halogenated oligosilane and isolation of the halogenated oligosilane with improved purity.

2.1. In the prior art, halogenated monosilanes such as HSiCl.sub.3 are purified by treatment with preferably polymeric organic compounds containing amino groups, and are separated out from these mixtures. This method cannot be used for halogenated oligosilanes because of the contained amino groups, since secondary reactions would lead to decomposition of the products. The new method should provide the desired products in high yield and purity without amino groups being used.

2.2. The purification of the halogenated oligosilanes is carried out in the presence of special purification agents, which convert contaminations such as, for example, FeCl.sub.2 into an insoluble and/or less volatile form. A separation of the products of completes the purification This method gives a high yield and avoids the problems associated with the prior art, such as, for example, long distillation times.

2.3. The method is suitable for the purification of, for example, Si.sub.2Cl.sub.6, Si.sub.3Cl.sub.8, Si.sub.4Cl.sub.10, and higher homologs. These find application, for example, in the deposition of silicon nitride layers in CVD processes.

The invention relates to a process for preparing higher halosilanes by disproportionation of lower halosilanes. The invention further relates to a process for preparing higher hydridosilanes from the higher halosilanes prepared by disproportionation. The invention further relates to mixtures containing at least one higher halosilane or at least one higher hydridosilane prepared by the process described. Finally, the invention relates to the use of such a mixture containing at least one higher hydridosilane for producing electronic or optoelectronic component layers or for producing silicon-containing layers.

The invention relates to a process for converting polychlorosilanes into hexachlorodisilane, by one or more trimeric polychlorosilanes or a trimeric polychlorosilane in a mixture with higher molecular weight polychlorosilanes being exposed to a gas discharge and hexachlorodisilane being formed and isolated.

A method for making chlorinated silazanes. The method comprises contacting: (a) a disilazane; (b) a chlorosilane; and (c) a catalyst which is a zinc salt of: (i) a sulfonic acid or (ii) a sulfonic acid imide.

A method for fabricating trihalodisilane, the method includes providing a halodisilane including at least four halogen atoms; reducing the halodisilane, using a mixed reducing agent including a first reducing agent represented by following Chemical Formula 1-1, in which R.sub.A is an alkyl group, and m and n are each independently 1 or 2, and m+n=3, and a second reducing agent represented by following Chemical Formula 2-1, in which R.sub.S is an alkyl group or an aryl group, p and q are each independently 1, 2, or 3, and p+q=4; and obtaining a product including a 1,1,1-trihalodisilane,

(R.sub.A).sub.m—Al—H.sub.n  [Chemical Formula 1-1]

(R.sub.S).sub.p—Sn—H.sub.q.  [Chemical Formula 2-1]