Method for crystal growth control
The growth of a crystalline body of a selected material is controlled so that the body has a selected cross-sectional shape. The apparatus is of the type which includes the structure normally employed in known capillary die devices as well as means for observing at least the portion of the surfaces of the growing crystalline body and the meniscus (of melt material from which the body is being pulled) including the solid/liquid/vapor junction in a direction substantially perpendicular to the meniscus surface formed at the junction when the growth of the crystalline body is under steady state conditions. The cross-sectional size of the growing crystalline body can be controlled by determining which points exhibit a sharp change in the amount of reflected radiation of a preselected wavelength and controlling the speed at which the body is being pulled or the temperature of the growth pool of melt so as to maintain those points exhibiting a sharp change at a preselected spatial position relative to a predetermined reference position. The improvement comprises reference object means positioned near the solid/liquid/vapor junction and capable of being observed by the means for observing so as to define said reference position so that the problems associated with convection current jitter are overcome. 7 figs.
- Assignee:
- Mobil Tyco Solar Energy Corp., Waltham, MA (United States)
- Patent Number(s):
- US 4290835; A
- Application Number:
- CNN: NAS7-100; PPN: US 6-161037
- OSTI ID:
- 7148695
- Resource Relation:
- Patent File Date: 19 Jun 1980
- Country of Publication:
- United States
- Language:
- English
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Apparatus for monitoring crystal growth
Apparatus for monitoring crystal growth