Patent ID: 6930329

Claim:
A group III nitride compound semiconductor comprising: a substrate; a buffer layer formed on said substrate into an island pattern comprising any of a dot pattern, a striped pattern, and a grid pattern such that substrate-exposed portions are formed in a scattered manner; a first group III nitride compound semiconductor layer Al x1 Ga y1 In 1−x1−y1 N, wherein 0≦x 1 ≦1, 0≦y 1 ≦1, 0≦x 1 ≦x 1 +y 1 ≦1, formed on said buffer layer; a second group III nitride compound semiconductor layer Al x2 Ga 2 In 1−x2−y2 N, wherein 0≦x 2 ≦1, 0≦y 2 ≦1, 0≦x 2 +y 2 ≦1, which causes epitaxial growth from at least an island of said first group III nitride compound semiconductor serving as nuclei so that said second group III nitride compound semiconductor keeps a an empty gap to said substrate-exposed portions and connects adjacent ones of said first group III nitride compound semiconductor; and a device layer made of gallium nitride group compound semiconductor formed on said second group III nitride compound semiconductor layer.