Method of automatic control of growing neck portion of a single crystal by the CZ method
US5183528A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 28, 1991 |
| Grant date | Feb 2, 1993 |
| Priority date | — |
| Expiry date | Feb 28, 2011 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T117/1008
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A method for automatically controlling growing a single crystal neck portion by the CZ method, comprising the steps of pulling up a seed crystal (30) at 2 mm/min. for five minutes so as to grow a single crystal 32; next measuring a diameter of the lower end of the crystal; modifying an electric power for heating a melt based on the difference between the measured diameter and a reference value; waiting for five minutes; keeping the electric power constant for 10 minutes with controlling the pulling up speed so as to approach the diameter of the crystal to the reference value and with measuring the pulling up speed repeatedly; and next modifying the power based on the difference between the mean speed and a reference value. The last two steps are repeated alternatively.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.