Process for controlling thermal history of Czochralski-grown silicon
US5779791A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 8, 1996 |
| Grant date | Jul 14, 1998 |
| Priority date | — |
| Expiry date | Aug 8, 2016 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T117/10
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A Czochralski method of producing a single crystal silicon ingot having a uniform thermal history from a silicon melt contained in a crucible coaxial with the ingot. In the process the pulling rate of the end-cone of the ingot is maintained at a relatively constant rate which is comparable to the pulling rate for the second half of the main body of the ingot. During the pulling of the end-cone of the crystal at a constant rate, the process may be further refined by, either independently or in combination, increasing the heat supplied to the melt, reducing the crystal rotation rate and/or reducing the crucible rotation rate. The second half of the main body of a single crystal silicon ingot grown in accordance with this process exhibits a relatively uniform axial concentration of flow pattern defects and amount of oxygen precipitated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.