Manufacture of pure silicon

摘要

Silane is purified by passage through two activated charcoal-containing traps in series, one trap being maintained at a temperature of - 68 DEG to - 88 DEG C., so as to remove arsine and/or phosphine, and the other being maintained at a temperature of 0 DEG to 30 DEG C., so as to remove diborane. As shown, a trap 2 is maintained at a temperature of - 78 DEG C. by means of solid carbon dioxide, and a trap 3 is maintained at atmospheric temperature. The traps may be in series in either order. Gas absorbed by the activated charcoal in each trap may be desorbed (a) by maintaining the trap at the temperature maintained in the other trap during absorption, or (b) by passing argon through the activated charcoal of each trap while at a temperature of 200 DEG C. Pure silicon may be produced from the purified silane by the method disclosed in Specification 745,698, e.g. by heating silane at a concentration of 0.3% to a temperature of 500 DEG to 800 DEG C.