RAW MATERIAL ALUMINA FOR PRODUCING SAPPHIRE SINGLE CRYSTAL AND METHOD FOR PRODUCING THE SAPPHIRE SINGLE CRYSTAL

摘要

PROBLEM TO BE SOLVED: To provide raw material alumina for the production of sapphire single crystals that is suitable for obtaining a sapphire single crystal ingot having a small strain.;SOLUTION: Raw material alumina is used for the production of sapphire single crystals and contains at least one kind of elements X's that are represented by the following (1)-(3). The content of the element X is in the range of ≥10 ppm and ≤1,000 ppm in terms of atoms, and the respective contents of silicon (Si), gallium (Ga), germanium (Ge) and tin (Sn) are ≤10 ppm in terms of atoms. The elements X's: (1) elements having an ionic radius of ≤0.3 Å and a valence of three, (2) elements having an ionic radius in the range of ≥0.4 Å and ≤0.5 Å and a valence of four, and (3) elements having an ionic radius in the range of ≥0.6 Å and ≤0.7 Å and a valence of four or five.;COPYRIGHT: (C)2014,JPO&INPIT