Apparatus for pulling up a single crystal
US5441014A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 22, 1993 |
| Grant date | Aug 15, 1995 |
| Priority date | — |
| Expiry date | Dec 22, 2013 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T117/1068
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
An apparatus for pulling up a single crystal according to Czochralski method is provided with a cylindrical first screen and a second screen. The first screen is arranged in the periphery of the zone of pulling up the single crystal, said screen being constituted by a heat absorbing body at the side facing a quartz crucible and by a heat insulator at the other side and being provided with respective outward and inward annular rims at the upper and lower ends thereof, the corner of said screen facing the crucible being formed in a curved or polygonal structure, and said annular rim at the lower end being positioned in the vicinity of filling the melt in the crucible. The second screen forming a parabolic shape in the section opening at its center while enclosing the crystal pulling-up zone and being provided at its upper end with an outward annular rim. Alternately, the second screen formed along the first screen may be provided within said first screen, and further the second screen may be provided with a forced cooling mechanism.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.