Patent ID: 8421107

Claim:
A group III nitride semiconductor light emitting device comprising: a substrate; a single crystal, group III nitride semiconductor layer formed on top of the substrate; an LED structure formed on top of the group III nitride semiconductor layer, and a buffer layer constituted of polycrystal or single crystal Al x Ga 1-x N (0≦x≦1) and having a thickness of 0.01 to 0.5 μm is laminated on top of the principal plane of the substrate by an Rf sputtering method using an a supply and a mechanism which is capable of moving the position of a magnet within a target, wherein the substrate includes a principal plane constituted of a plurality of convex portions, the entire surface thereof being non-parallel to a (0001) C plane of the substrate, and a flat surface configured from the C plane, the convex portions have a base portion width d 1 of 0.05 to 1.5 μm and a height h of 0.05 to 1 μm, the group III nitride semiconductor layer is formed by causing a group III nitride semiconductor to grow epitaxially on top of the principal plane of the substrate so as to cover the buffer layer, the full width at half maximum of the X-ray diffraction (XRD) of the (10-10) plane of the group III nitride semiconductor layer ranges from 150 to 180 arcsec, and the full width at half maximum of the X-ray diffraction (XRD) of the (0002) plane of the group III nitride semiconductor layer ranges from 30 to 50 arcsec, and the base portion width d 1 of the convex portions and the top portion thickness H 2 of the group III nitride semiconductor layer at the positions of the top portions of the convex portions have a relationship expressed by a formula: H 2 =kd 1 (wherein 0.5<k<5, and H 2 =0.5 μm or more).