Patent ID: 8053811

Claim:
A Group 3-5 nitride semiconductor multilayer substrate comprising: a base substrate; a semiconductor layer with which the base substrate is coated; a mask with which a portion of an upper surface of the semiconductor layer is coated; and a Group 3-5 nitride semiconductor crystalline layer with which both an exposed surface of the upper surface of the semiconductor layer, which is not coated with the mask, and the mask are coated, wherein voids are included within the semiconductor layer and are between the mask and the base substrate, wherein the semiconductor layer is lower in crystallinity than the Group 3-5 nitride semiconductor crystalline layer, and wherein the semiconductor layer is a buffer layer of a material having the general formula: In x Ga y Al z N wherein 0≦x≦1, 0≦y≦1, 0≦z≦1 and x+y+z=1, the buffer layer being grown at a temperature of 400° C. to 700° C.