METHOD OF PRODUCING GGG SINGLE CRYSTAL

摘要

PURPOSE:The content of oxygen gas in the nitrogen gas atmosphere is made different between the first half and the latter half in the growth of GGG single crystal to inhibit the contamination with Ir inclusion and increase the length of good-quality crystal. CONSTITUTION:In the production of GGG single crystal by the chokralsky method, the oxygen gas content in the nitrogen gas atmosphere is adjusted to 0.5-3vol% at the first half of the crystal bowl lifting including the heating before the raw material melt down. Then, the content is increased by 1.2-1.5 times that in the first half at the latter half. Thus, the contamination with Ir inclusion is prohibited by controlling the atmosphere to produce GGG single crystal with good-quality crystal length increased.