Boron, phosphorus, arsenic, antimony and other impurities are at least partially removed from a mixture containing at least one chlorosilane and/or organochlorosilane by a) contacting the liquid mixture with a carrier material functionalized with an amidoxime of the general structural formula (I),

##STR00001##

where CAR=carrier material and R.sup.1, R.sup.2 are independently of one another H, alkyl, alkenyl, aryl, alkylaryl; and b) optionally removing the functionalized carrier material.

A process for removing metallic impurities from halogenated silicon compounds, such as chlorosilane monomers and/or chlorinated polysilanes is disclosed. The process involves treating a halogenated silicon compound with a tertiary amine and thereafter a suitable grade of activated carbon.

This disclosure is to make it possible to easily stabilize a chlorosilane polymer while preventing a solid chlorosilane polymer from being generated. Disclosed is a method for stabilizing a chlorosilane polymer generated secondarily in a step of a chemical vapor deposition method using chlorosilane-based gas, the method including: a step of bringing alcohol into contact with the chlorosilane polymer, degrading the chlorosilane polymer to alkoxide, hydrogen chloride and hydrogen, and diluting the degraded alkoxide with the alcohol; and a step of performing hydrolysis for the alkoxide.

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.

A system for purifying trichlorosilane that can prevent re-contamination by the dissociation of an adduct occurring in association with the conversion of high boiling point compounds or the remaining of impurities due to an equilibrium constraint is provided. Trichlorosilane containing impurities serving as a donor or an acceptor in silicon crystals is supplied to a multistage impurity conversion step. These impurities in the trichlorosilane are converted into high boiling point compounds in the presence of a distillation aid. A plurality of impurity conversion step sections (10.sup.1 to 10.sup.n) are connected in series, and any of the impurity conversion step sections comprises a reception section a for the trichlorosilane from the preceding stage section, an introduction section b for the distillation aid, a transmission section c for the trichlorosilane to the subsequent stage section, and a drain section d that discharges a remainder out of the impurity conversion step section.

This disclosure is to make it possible to easily stabilize a chlorosilane polymer while preventing a solid chlorosilane polymer from being generated. Disclosed is a method for stabilizing a chlorosilane polymer generated secondarily in a step of a chemical vapor deposition method using chlorosilane-based gas, the method including: a step of bringing alcohol into contact with the chlorosilane polymer, degrading the chlorosilane polymer to alkoxide, hydrogen chloride and hydrogen, and diluting the degraded alkoxide with the alcohol; and a step of performing hydrolysis for the alkoxide.

A process for removing metallic impurities from halogenated silicon compounds, such as chlorosilane monomers and/or chlorinated polysilanes is disclosed. The process involves treating a halogenated silicon compound with a tertiary amine and thereafter a suitable grade of activated carbon.

A system for purifying trichlorosilane that can prevent re-contamination by the dissociation of an adduct occurring in association with the conversion of high boiling point compounds or the remaining of impurities due to an equilibrium constraint is provided. Trichlorosilane containing impurities serving as a donor or an acceptor in silicon crystals is supplied to a multistage impurity conversion step. These impurities in the trichlorosilane are converted into high boiling point compounds in the presence of a distillation aid. A plurality of impurity conversion step sections (10.sup.1 to 10.sup.n) are connected in series, and any of the impurity conversion step sections comprises a reception section a for the trichlorosilane from the preceding stage section, an introduction section b for the distillation aid, a transmission section c for the trichlorosilane to the subsequent stage section, and a drain section d that discharges a remainder out of the impurity conversion step section.

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.

First, at least one of silanol and a siloxane compound is generated in a chlorosilane (S101). In the step, for example, an inert gas having a moisture concentration of 0.5 to 2.5 ppm is brought into contact with the chlorosilane to dissolve the moisture, and at least one of silanol and a siloxane compound is generated through a hydration reaction of a moiety of the chlorosilane. Next, a boron-containing compound contained in the chlorosilane is reacted with the silanol or the siloxane compound, thereby converting the boron-containing compound to a boron oxide (S102). Through the step (S102), the boron-containing compound being a low boiling point compound is converted to a boron oxide being a high boiling point compound, and therefore the difference in boiling point from the boiling point of chlorosilane becomes larger to make later separation easy.