GROUND SUBSTRATE FOR CRYSTAL GROWTH AND METHOD OF PRODUCING SUBSTRATE USING THE SAME

摘要

PROBLEM TO BE SOLVED: To significantly reduce crystal defects in an epitaxial crystal layer formed on a substrate of a different material, without complicating a process. SOLUTION: A GaN film 12 is formed on a sapphire (Al2O3) substrate 11 having a (0001) surface and then the GaN film 12 is wet etched while leaving the GaN film 12 in an island form. The upper part of the GaN film 12 having the island form is constituted of a single crystal layer. A GaN film 15 almost free from crystal defects is obtained by epitaxial growth in the state that the GaN film having the island form is left.