Method of controlling floating zone
US4931945A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 5, 1988 |
| Grant date | Jun 5, 1990 |
| Priority date | — |
| Expiry date | Dec 5, 2008 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T117/1008
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A method of controlling a floating zone applied to a crystal manufacturing system based on the FZ method and designed to enable the diameter at the crystallization boundary and the axial length of the floating zone or other similar quantities to desired values, in which a floating zone (20) is imaged with an imaging device (30); geometric quantities of the floating zone is measured from the image thereby obtained; the electric power (P) supplied to an induction heating coil (12) and the speed (V.sub.p) at which a raw-material rod (16) is moved relative to the induction heating coil so that the geometric quantities become equal to desired values. The geometric values include one Z.sub.i of the axial length of the floating zone, the distance (L) between the induction heating coil and a crystallization boundary (24) and the diameter (D.sub.n) of a melt neck portion located on the side of the crystallization boundary at a predetermined distance from the induction heating coil, and one D.sub.i of the diameter (D.sub.s) of the crystallization boundary and the diameter (D.sub.m) of a melt shoulder portion (34) located between the crystallization boundary and the restricted portions at a p…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.