| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To prevent contamination by hardly soluble matter into sapphire melt inside a molybdenum crucible. <P>SOLUTION: This method for producing a sapphire single crystal by the CZ method comprises: a pre-combusting step of subjecting the molybdenum crucible 14 to a heat treatment in a reducing atmosphere in a chamber 11, thereby removing an oxide film at its surface; a melting step of introducing a sapphire raw material into the molybdenum crucible 14 and melting the same, thereby obtaining the sapphire melt 21; and a pulling step of pulling a seed crystal soaked in the sapphire melt 21, thereby obtaining the sapphire single crystal 20. The reducing atmosphere is a hydrogen atmosphere with a hydrogen concentration of≥10 ppm and≤5 vol.%. <P>COPYRIGHT: (C)2013,JPO&INPIT</p> |
