Process for producing single-crystal sapphire

A process for producing single-crystal sapphire, comprising the steps of:

• growing single-crystal sapphire by pulling up the single-crystal sapphire from a melt of aluminum oxide within a crucible placed in a chamber;
• and
• separating the single-crystal sapphire from the melt by further pulling up the single-crystal sapphire to pull away from the melt while the chamber is supplied with a mixed gas including oxygen and an inert gas, the oxygen having a concentration set at not less than 1.0 vol % nor more than 5.0 vol %.

A process for producing single-crystal sapphire including pulling up single-crystal sapphire from a melt of aluminum oxide within a crucible, the process comprising the steps of:

• growing the single-crystal sapphire by pulling up the single-crystal sapphire from the melt in an atmosphere having an oxygen concentration set at a first concentration;
• and
• separating the single-crystal sapphire from the melt by further pulling up the single-crystal sapphire to pull away from the melt in an atmosphere having an oxygen concentration set at a second concentration that is higher than the first concentration.