Crystal growth combining float zone technique with the water cooled RF container method
US3936346A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 26, 1973 |
| Grant date | Feb 3, 1976 |
| Priority date | — |
| Expiry date | Dec 26, 1993 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S117/90
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
The disclosure relates to the growth of single crystal material from polycrystalline material by combining the pedestal and cold crucible techniques to yield a method of producing large, high purity single crystals on a commercial scale. The method includes feeding a bar of polycrystalline material, such as silicon, into a cold cage which can be a cold silver crucible or the like having an aperture in the bottom thereof to permit insertion of the polycrystalline feed bar. An RF coil surrounds the cold cage and melts the silicon as it reaches into the cage, the RF coil providing a temperature to the silicon material which is slightly above the melting point thereof. A rod of single crystal material, the same as the feed bar, is positioned in the melt from the top surface of the cold cage and acts as a seed crystal. The single crystal rod is then pulled upwardly from the cage while polycrystalline silicon is fed into the cage through the aperture in the bottom thereof. By continuously forcing the polycrystalline rod into the cage and pulling a rod at the top of the cage, a large single crystal can be grown while maintaining only a small melt volume. The diameter of the single crystal…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.