Control of oxygen concentration in single crystal pulled up from melt containing Group-V element
US5524574A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Aug 17, 1994 |
| Grant date | Jun 11, 1996 |
| Priority date | — |
| Expiry date | Aug 17, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S117/916
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
The amount of Group-V element included in a melt 6 has the close relationship with the oxygen concentration of the melt 6. This relationship is utilized for controlling the oxygen concentration of a single crystal 8 at a high level. The content of Group-V element is calculated from the weight of the melt 6 gauged by a gravimeter 11 and compared with a preset value in a control unit 12. When the calculated content is smaller than the preset value, the control signal to additionally supply Group-V element to the melt 6 is outputted from the control unit 12 to a feeder 14. When the calculated content is larger than the preset value, the control signal to supply a raw material to the melt 6 is outputted to another feeder 13.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.