Single crystal pulling apparatus
US5316742A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 8, 1991 |
| Grant date | May 31, 1994 |
| Priority date | — |
| Expiry date | Oct 8, 2011 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T117/1068
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A single crystal pulling apparatus using Czochralski method includes a first screen in the shape of a hollow round cylinder. One side of the first screen facing a quartz crucible is made of a heat absorbent material and another side of the first screen is made of a heat insulator material. The upper and lower ends of the first screen have an outwardly extending flange and an inwardly extending flange, respectively. The first screen surrounds a single crystal pulling zone such that its lower flange is positioned near a melt charged zone in the crucible. The apparatus also includes a second screen positioned inside the first screen. The vertical section of the second screen has the shape of a substantially parabola and the center of the bottom of the second screen is open and surrounds the single crystal pulling zone. The upper end of the second screen has an outwardly extending flange. The apparatus increases the pulling speed of a grown single crystal and improves preventing degree of dislocation in the grown single crystal due to contamination of the grown single crystal with impurities.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.