GROUP III NITRIDE COMPOSITE SUBSTRATE, MANUFACTURING METHOD THEREFOR, AND GROUP III NITRIDE SEMICONDUCTOR DEVICE MANUFACTURING METHOD

摘要

Provided are a group III nitride composite substrate having a low sheet resistance and produced with a high yield, and a method for manufacturing the same, as well as a method for manufacturing a group III nitride semiconductor device using the group III nitride composite substrate. A group III nitride composite substrate (1) includes a group III nitride film (13) and a support substrate (11) formed from a material different in chemical composition from the group III nitride film (13). The group III nitride film (13) is joined to the support substrate (11) in one of a direct manner and an indirect manner. The group III nitride film (13) has a thickness of 10 µm or more. A sheet resistance of a group III-nitride-film (13)-side main surface (13m) is 200 ©/sq or less. A method for manufacturing the group III nitride composite substrate (1) includes the steps of: bonding the group III nitride film (13) and the support substrate (11) to each other in one of a direct manner and an indirect manner; and reducing the thickness of at least one of the group III nitride film (13) and the support substrate bonded to each other.