Really substantial purity silicon for semiconductors is received using the Siemens approach; the silicon is reacted to make trichlorosilane, which happens to be first purified by distillation, then reacted with purified hydrogen on higher purity silicon rods at 1150 oC to yield higher purity, polycrystalline silicon with hydrochloric acid byproduct. https://glasslinedcastironpipe54207.wikiadvocate.com/7010748/top_silicon_carbide_semiconductor_secrets