Method of purifying metallurgical silicon by directional solidification
US7799306B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 2, 2007 |
| Grant date | Sep 21, 2010 |
| Priority date | — |
| Expiry date | Nov 2, 2027 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02P70/50
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
The method enables metallurgical silicon to be purified by directional solidification to obtain solar or photovoltaic grade silicon. A crystallization step uses at least one silicon seed, preference of solar grade or even microelectronic grade, having for example a purity substantially equal to or greater than a predetermined purity of the solar-grade silicon. The silicon seed which covers the bottom of the crucible can come from a previous crystallization or be formed by a silicon wafer. The use of a single-crystal or textured multi-crystal seed enables crystallographic orientation of the solar-grade silicon. An intermediate layer of solid metallurgical silicon can be arranged on the silicon seed and a metallurgical silicon feedstock is arranged on the intermediate layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.