Method for pulling single crystals
US4980015A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 1, 1989 |
| Grant date | Dec 25, 1990 |
| Priority date | — |
| Expiry date | Jun 1, 2009 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T117/1052
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
In a method for pulling a single crystal, employing a double crucible assembly, the dopant concentration of the molten raw material in an inner crucible prior to the pulling, is raised to a value higher than the dopant concentration C of the molten raw material in the inner crucible at the steady state. Furthermore, at the initial stage of the pulling, the raw material having a dopant content ratio of no greater than kC is introduced into the outer crucible at a rate greater than the rate of decrease of the molten raw material within the inner crucible during the pulling, to achieve a concentration ratio of dopant between the inner and outer crucibles at a target value. Subsequently, the raw material having kC as the dopant content ratio is introduced into the outer crucible, at a rate equal to the rate of decrease of the molten raw material during the pulling.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.