GB834380A - A method of producing purified silicon halide - Google Patents

Abstract

Boron trichloride is removed from silicon tetrachloride by the formation of an addition compound with one or more of the following: cyanogen chloride, propionitrile, cyanamide, nitrobenzene, diamethylaniline, azobenzene, caprolactam, benzaldehyde, methylethylketone, dimethylglyoxime, valerolactone, dioxane, diethylphosphine, triphenylchloromethane, tri, phenylfluoromethane, phosphorus oxychloride-phosphorus trichloride, phosphorus pentachloride, ferric chloride, and aluminium trichloride, The silicon tetrachloride is thereafter distilled. It may be drawn off from the reaction vessel through a quartz tube to the distillation vessel by means of a weak suction pump connected to the distillation vessel. Reaction may be effected at a temperature of -70-50 DEG C., preferably 0-20 DEG C. The resulting silicon tetrachloride may be decomposed to form silicon by high-frequency induction heating optionally in the presence of a gaseous reducing agent, and may be absorbed in an already formed drop of silicon adhering to a carrier moving so as to effect crystallization of silicon on to the carrier.