Dislocation-free growth of silicon semiconductor crystals with <110> orientation
US4002523A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 19, 1975 |
| Grant date | Jan 11, 1977 |
| Priority date | — |
| Expiry date | May 19, 1995 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC30B15/36
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
The disclosure relates to the growth of semiconductor single crystals, i.e., either by the pedestal method or by the Czochralski method, free from dislocations, particularly in the difficult directions of growth, such as <110>. The method causes dislocations parallel to the growth axis to grow away from the axis under the influence of a changing crystal diameter. The thickness of the stem portion of the crystal is controlled so that it has first a long thin portion to get rid of dislocations on the {111} planes that are inclined to the <110> axis and then a portion in which the residual dislocations are permitted to terminate at the surface. The latter portion may be generated in several ways. One way is to follow the long narrow diameter portion with a section of substantially larger diameter followed by a further narrow diameter portion. This combination is repeated one or more times to insure freedom from dislocations in the resulting crystal. By having the alternate thin and thick regions, the dislocations are gradually moved away from the axis of the crystal and toward the periphery where they will have a greater probability of terminating on a surface, thereby removing the di…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.