GB851290A - Method of producing high quality silicon for electric semiconductor devices - Google Patents

Abstract

<PICT:0851290/III/1> Silicon is produced by the interaction of a silicon halide, e.g. silicon tetrachloride, and atomic hydrogen at normal or elevated temperature, e.g. 200-300 DEG C. The atomic hydrogen may be produced by the passage of an electric discharge through molecular hydrogen at a pressure of 1 m.m. The discharge may be produced by an alternating current of 3000-5000 volts. The silicon halide may be vaporised at a thermostatically controlled temperature, and in addition may be mixed in the vapour state with molecular hydrogen before contact with the atomic hydrogen. The silicon produced may be deposited on a rod, which may be inductively heated, and may be rotated and withdrawn from the reaction zone as deposition of silicon proceeds. As shown hydrogen passes through a U-shaped discharge tube 1 from a valved inlet 5 into a reaction tube 2 where it is admixed with vaporous silicon halide admitted through a concentrically arranged tube 7 from a vaporising vessel 9 heated to a thermostatically controlled temperature. The silicon produced is deposited on a carrier 14 heated by an induction coil 15. The reaction product gas passes through a separating vessel 11, a freezing-out trap 12, a valve 13, and a vacuum pump (not shown).