Aluminum chloride is separated from a silane mixture containing aluminum chloride by reacting the aluminum chloride with a compound reactive therewith which forms an ionic liquid or solid, and separating the ionic liquid or solid from the now-purified silane.

A process for producing polysilicon, includes a) depositing polycrystalline silicon on filaments using reaction gas containing silicon-containing component (SCC) containing trichlorosilane, and hydrogen, wherein molar saturation of SCC based on hydrogen is at least 25%; b) feeding offgas from the deposition into a cooling apparatus, i) wherein condensed offgas components containing SiCl.sub.4 are conducted to an apparatus which enables distillative purification of the condensate, and ii) non-condensing components are conducted to an adsorption or desorption unit; c) obtaining a first stream of non-condensing components purified by adsorption and containing hydrogen; and d) obtaining, during adsorption unit regeneration, a second stream of non-condensing components, containing SiCl.sub.4 which is then preferably supplied to a converter for conversion of SiCl.sub.4 to trichlorosilane. A process for depositing polysilicon on filaments with a reaction gas includes a SCC and hydrogen, wherein molar saturation of SCC based on hydrogen is at least 25%.

The present invention relates to an apparatus and a method for producing polycrystalline silicon having a reduced amount of boron compound impurities. Especially, the boron compounds are removed from the process for producing polycrystalline silicon, while the trichlorosilane is purified by distillation. The invention feeds condensed liquid trichlorosilane into a primary distillation tower below the liquid level inside the primary distillation tower thereby scrubbing the boron impurities upon contact inside the primary distillation tower. There result is trichlorosilane leaving the primary distillation tower with total amount of boron at least 10 times less.

A column includes a column head, a column sump and a tube-shaped column shell disposed therebetween, two or more reaction zones lying above each other which each accommodate a catalyst bed, in which catalyst beds chlorosilanes disproportionate into low-boiling silanes, which form an ascending stream of gas, and also into high-boiling silanes which form a downwardly directed stream of liquid, within the column shell and along the column axis, two or more rectificative separation zones, the reaction zones and the separation zones alternate along the column axis, the separation zones are configured such that the stream of gas and the stream of liquid meet in the separation zones, and the reaction zones are configured such that the downwardly directed stream of liquid is led through the catalyst beds, whereas the upwardly directed stream of gas passes the catalyst beds in spatial separation from the stream of liquid.

There is provided trichlorosilane purification technology in which it is unnecessary to discharge large amounts of chlorosilanes oat of the system in the production of high-purity trichlorosilane from a chlorosilane fraction containing hydrocarbons and in which the reaction control can also be easily performed. In the present invention, the step of converting hydrocarbons contained in a chlorosilane fraction into low-boiling materials by thermal decomposition has been provided in the purification system in order to easily separate the hydrocarbons. Thereby, the conversion of hydrocarbons into low-boiling materials by thermal decomposition and the separation are performed in the trichlorosilane purification cycle, and it is unnecessary to discharge large amounts of chlorosilanes out of the system. As a result, the trichlorosilane production efficiency is increased, and the problem of yield reduction of polycrystalline silicon does not arise either.

A method for producing purified chlorosilanes includes bringing crude chlorosilanes, such as crude trichlorosilane and crude silicon tetrachloride, which contain a boron compound and/or a phosphorus compound, into contact with chlorine (preferably 1 ppm mole to 3000 ppm mole with respect to 1 mole of crude chlorosilanes) in presence of alkylphenol such as 2-methylphenol, and then distilling the crude chlorosilanes.

Methods of recovering hydrohalosilanes from reaction residues are disclosed. An inorganic halosilane slurry comprising (i) tetrahalosilane, trihalosilane, dihalosilane, or any combination thereof, (ii) silicon particles, and (iii) heavies is passed through a thin-film dryer to remove halosilanes and form a solid residue comprising silicon particles. Heavies also may be removed as the slurry passes through the thin-film dryer.

The present invention provides a technique which allows stable use of an ion-exchange resin for removing boron impurities over a long period of time in the purification step of a silane compound or a chlorosilane compound. In the present invention, a weakly basic ion-exchange resin used for the purification of a silane compound and a chlorosilane compound is cleaned with a gas containing hydrogen chloride. When this cleaning treatment is used for the initial activation of the weakly basic ion-exchange resin, a higher impurity-adsorbing capacity can be obtained. Further, use of the cleaning treatment for the regeneration of the weakly basic ion-exchange resin allows stable use of the ion-exchange resin for a long time. This allows reduction in the amount of the resin used in a long-term operation and reduction in the cost of used resin disposal.

The invention relates to a process for producing trimeric and/or quaternary silicon compounds or trimeric and/or quaternary germanium compounds, where a mixture of silicon compounds or a mixture of germanium compounds is exposed to a nonthermal plasma, and the resulting phase is subjected at least once to a vacuum rectification and filtration.

Provided is a method for preparing diiodosilane including: reacting a compound represented by the following Chemical Formula 1 with iodine (I.sub.2) to prepare diiodosilane (SiH.sub.2I.sub.2), and the method may secure process safety and productivity and provide high-purity diiodosilane:

##STR00001## wherein R and A are as defined in the specification.