PROCESS FOR PRODUCING SINGLE-CRYSTAL SAPPHIRE, AND SINGLE-CRYSTAL SAPPHIRE SUBSTRATE

摘要

A process for producing a sapphire ingot includes: a heating step (S101) in the solid phase in which solid aluminum oxide (alumina) filled in a crucible in a heating furnace is heated and held at a temperature less than the melting point (2050°C); a melting step (S102) in which the aluminum oxide in the crucible is melted; a heating step (S103) in the liquid phase in which the aluminum oxide is heated and held at a temperature higher than the melting point thereof; a shoulder-part formation step (S105) in which a seed crystal is pulled up while being rotated to form a shoulder part beneath the seed crystal; and a straight-part formation step (S106) in which the shoulder-part is pulled up while being rotated via the seed crystal while the lower end part of the shoulder-part is kept in contact with the alumina melt to form a straight part beneath the shoulder part. Thus, a process for producing a single-crystal sapphire substrate with few metal impurities and crystal defects (air bubbles), and a single-crystal sapphire substrate are provided.