Question

How is ultrapure elemental silicon obtained?

Answer 1

1. Silicon is first obtained from silica (sand) by heating it with coke at high temperature in an electric furnace.
2. The crude silicon contains impurities and is then purified by chemical methods.
3. A common method involves converting silicon to trichlorosilane (SiHCl₃) by reaction with HCl gas.
4. Trichlorosilane is purified by fractional distillation.
5. Pure trichlorosilane is reduced with ultrapure hydrogen to deposit ultrapure silicon.
6. The deposited silicon is collected as ultrapure elemental silicon, suitable for electronic uses.