Patent ID: 7115486

Claim:
A method for manufacturing a GaN group semiconductor crystal defined Al x Ga 1−x−y In y N wherein 0≦x≦y1 and 0≦y≦1, which method comprises the following steps of: (a) preparing a substrate for crystal growth, wherein the substrate is made of sapphire (C-plane, A-plane, R-plane), SiC (6H, 4H, 3C), Si, Spinel, ZnO, GaAs, or NGO, and a crystal growth plane of the substrate is a plane having concave parts with bottom surfaces formed by etching the original substrate, which consequently contains concaves and convexes formed by the concave parts and the remaining convex parts, and wherein not more than 40% of the crystal growth plane is an area occupied by the convex parts, (b) growing the GaN group crystal on the crystal growth plane having concaves and convexes by vapor phase growth without forming a mask in any part, connecting the crystals grown from the upper parts of the convex parts to each other to form a GaN group crystal layer and forming a cavity between the crystal layer and the substrate in the concave part, and (c) separating the GaN group crystal layer from the substrate at said cavity part.