Process of refining impure silicon to produce purified electronic grade silicon
US4092446A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 31, 1974 |
| Grant date | May 30, 1978 |
| Priority date | — |
| Expiry date | Jul 31, 1994 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S423/16
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A balanced closed cycle silicon refinery has been developed for producing electronic silicon from industrial grade silicon. Impurities comprising approximately 1% of the industrial grade silicon are removed during the refinery process to produce the purified silicon, while only a relatively small percentage of make-up chemicals are added to the system. In the refinery, hydrogen chloride is reacted with the impure silicon in a halide reactor to provide trichlorosilane and silicon tetrachloride and hydrogen. The trichlorosilane and/or silicon tetrachloride are purified to remove the impurities, and then reacted with the hydrogen from the halide reactor in a fluidized bed reactor to produce the purified silicon and an effluent comprised of unreacted trichlorosilane, silicon tetrachloride, hydrogen, and the by-product hydrogen chloride. These materials are separated and the trichlorosilane and silicon tetrachloride and hydrogen are returned to the silicon reactor while the hydrogen chloride is returned to the halide reactor to be reacted with additional industrial grade silicon in a closed cycle process.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.