Purification of silane for semiconductor mfr. - by passing through series of absorption zones; liquefying and distilling

摘要

Impure silane is improved by passing the mixt. through a series of zones in a closed system. The mixt. is first passed as a gas into a zone contg. granular or porous carbon capable of absorbing substances at -40 to -80 degrees C and the silane and gaseous impurities are recovered in the gaseous state. It is then passed into a zone contg. granular or porous magnesium silicate having similar properties. The gas mixt. is then passed into a distd. zone where >95 wt. % of the silane is liquefied while the impurities remain gaseous. Finally the silane is then distilled and recovered. Used for the mfr. of Si for electronic use. Very high purity Si is obtd.