COMPOUND GaN SUBSTRATE AND METHOD FOR PRODUCING SAME, AND GROUP III NITRIDE SEMICONDUCTOR DEVICE AND METHOD FOR PRODUCING SAME

摘要

A composite GaN substrate (1) of the present invention includes: a conductive GaN substrate (10) having a specific resistance of less than 1 ©cm; and a semi-insulative GaN layer (20) disposed on the conductive GaN substrate (10), having a specific resistance of 1 × 10 4 ©cm or more, and having a thickness of 5 µm or more. A group III nitride semiconductor device (2) of the present invention includes: the above-described composite GaN substrate (1); and at least one group III nitride semiconductor layer (30) disposed on the semi-insulative GaN layer (20) of the composite GaN substrate (1). In this way, there can be obtained the composite GaN substrate (1) and the semiconductor device (2) each having a high characteristic with reasonable cost.