Method for production of high purity silicon

US6887448B2 · kind B2 · utility

Assignee

• SOLARWORLD AG · DE

Inventors

• Hans-Dieter Block · Cologne, DE
• Leslaw Mleczko · Bochum, DE
• Hans-Joachim Leimkühler · Leverkusen, DE
• Rainer Weber · Leverkusen, DE
• Knud Werner · Krefeld, DE
• Dietmar Schwanke · Monheim, DE
• Johannes-Peter Schafer · Lingen (Ems), DE
• Gebhard Wagner · Odenthal, DE

Key dates

• Filing date: Nov 21, 2001
• Grant date: May 3, 2005
• Expiry date: Nov 21, 2021

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02P70/50
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

The invention relates to a method for the production of high purity silicon, characterized by the following steps: a) reaction of metallic silicon with silicon tetrachloride (SiCl4), hydrogen (H2) and hydrochloric acid (HCl) at a temperature of 500 to 800° C. and a pressure of 25 to 40 bar to give a trichlorosilane-containing (SiHCl3) feed gas stream, b) removal of impurities from the resultant trichlorosilane-containing feed gas stream by scrubbing with condensed chlorosilanes at a pressure of 25 to 40 bar and a temperature of 160 to 200° C. in a multi-stage distillation column, to give a purified trichlorosilane-containing feed gas stream and a solid-containing chlorosilane suspension and a distillative separation of the purified feed gas stream into a partial stream essentially comprising SiCl4 and a partial stream, essentially comprising SiHCl3, c) disproportionation of the SiHCl3-containing partial stream to give SiCl4 and SiH4, whereby the disproportionation is carried out in several reactive/distillative reaction zones, with a counter-current of vapour and liquid, on catalytic solids at a pressure of 500 mbar to 50 bar and SiHCl3 is introduced into a first reaction zone, the…