| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a sapphire single crystal having no foams, capable of suppressing increase of the impurity concentration of raw material molten liquid even when reuse of the raw material molten liquid is repeated, in production of a sapphire ingot by a Czochralski method.SOLUTION: A sapphire ingot is produced by a Czochralski method, and a shoulder part and a tail part of the sapphire ingot are cut off to obtain a core, and the cut-off shoulder part and tail part are used as a part of a production raw material of the sapphire ingot by the Czochralski method of another batch. |
