Patent ID: 7691356
Filing Date: 2010-04-06
Classification: C01B,C23C

Abstract:
1. A method for producing trichiorosilane, comprising: chlorinating a by-product mixture obtained from a process for producing polycrystalline silicon to form a distillate comprising tetrachiorosilane (STC); hydrogenating the tetrachiorosilane (STC) comprising distillate formed in the chlorination to form a chlorosilane effluent comprising trichlorosilane (TCS) and methyl chlorosilane (MeCS); removing donor and acceptor impurities from the chlorosilane effluent; separating the chlorosilane effluent from which donor and acceptor impurities are removed into a mixture distillate containing hyper-hydrogenated chlorosilanes and a trichlorosilane (TCS) distillate; recycling the trichlorosilane distillate to production of polycrystalline silicon; distilling the methyl chlorosilane (MeCS) produced with residual carbon from the reactor or present in the silicon in the hydrogenation; circulating the methyl chlorosilane distillate to the chlorination; and chlorinating the methyl chlorosilane to form a hyper-chlorinated methyl chlorosilane wherein the by-product mixture comprises a poly-silane represented by the chemical formula: wherein n is an integer of 2 to 4 and m is an integer of 0 to 2(n+1).