Process for preparing polysilicon with diminished hydrogen content by using a two-step heating process
US5326547A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 26, 1993 |
| Grant date | Jul 5, 1994 |
| Priority date | — |
| Expiry date | Apr 26, 2013 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01B33/037
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
The hydrogen content of polysilicon can be reduced by heat treatment. The process is preferably conducted on polysilicon particles in bead-like form produced by chemical vapor deposition in a fluidized bed. The heat treatment is preferably conducted at a temperature of 1020.degree.-1200.degree. C. for a time from about 6 hours to about 1 hour sufficient to reduce the hydrogen content, and insufficient to cause agglomeration of the particles being treated. In order to reduce the tendency of particles to agglomerate at the process temperature employed, the particle bed is preferably maintained in motion during the dehydrogenation. The products produced by the process can have a hydrogen content of 30 ppma or less. These improved products can be used to produce monocrystalline silicon for the production of semiconductor devices.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.