Patent ID: 7591895
Filing Date: 2009-09-22
Classification: C30B,Y10T

Abstract:
1. A method for producing crystals wherein the crystals are grown from a liquefying raw material in a crucible retained in a furnace and slowly cooling a solution of the raw material in the crucible from below upward, said method being characterized in that: heating heaters are controlled so as to have a lower temperature area than a crystallization temperature downward and a higher temperature area than the crystallization temperature above thereof in a temperature distribution in a vertical direction in the furnace in which the crucible is retained, a resupply raw material supplied from a raw material supply apparatus placed above the crucible is liquefied on a surface of a reflection plate placed above the crucible by heating at the same temperature as in the higher temperature area, held on the surface of the reflection plate for a certain time for a soaking treatment, and supplied into the crucible from the reflection plate, and the temperature in the higher temperature area is a soaking temperature which is 20 to 100° C. higher than the crystallization temperature.