SELF-SUPPORTING GALLIUM NITRIDE CRYSTAL SUBSTRATE AND METHOD OF MANUFACTURING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a self-supporting gallium nitride crystal substrate having a dark spot density of <2×10/cmand having a surface with a nonpolar or semi-polar plane orientation; and a method of manufacturing the self-supporting gallium nitride crystal substrate.SOLUTION: In a method of manufacturing a self-supporting gallium nitride crystal substrate: using a sapphire base substrate wherein a plurality of groove parts each having a sidewall tilting to a main plane of the base substrate and consisting of a c-plane of a sapphire single crystal, for example are formed, a gallium nitride crystal layer is formed by crystal growth in the lateral direction from the sidewall; the crystal growth is carried out until the film thickness of the crystal layer becomes ≥100 μm, preferably ≥300 μm; and then the sapphire base substrate and the gallium nitride crystal layer are separated from each other by cooling.