ULTRAHIGH PURITY SILANE AND SILICON PRODUCTION

摘要

12539 ULTRAHIGH PURIIY SILANE AND SILICON PRODUCTION Tri-and dichlorosilanes formed by the reaction of metallurgical silicon, hydrogen and silicon tetrachloride as subjected to disproportionation in the presence of an ion exchange resin to form high purity silane, with unreacted and by-product materials being recycled. Said chlorosilanes are passed through distillation zones and disproportionation reaction zones to progressively replace chlorine molecules with hydrogen molecules so that product silane is eventually recovered from the process and silicon tetrachloride is recycled for further hydrogenation. The process flow employed ensures that all of the process fluid passes through at least one disproportionation reaction zone for contact with ion exchange resin therein. This ensures that boron impurities present in said fluid are removed to desirably low levels such that ultrahigh purity silane product can be produced, This product can be decomposed in a fluid bed or free space reactor to form ultrahigh purity silicon and by-product hydrogen that can be recycled. The resulting ultrahigh purity silicon can be employed for solar cell and for electronic applications S P E C I F I C A T I O N