Patent attributes
In heteroepitaxially growing a group-III nitride semiconductor on a Si single crystal substrate, the occurrence of cracks initiating in the wafer edge portion can be suppressed. Region A is an outermost peripheral portion outside the principal surface, being a bevel portion tapered. Regions B and C are on the same plane (the principal surface), region B (mirror-surface portion) being the center portion of the principal surface, and region C a region in the principal surface edge portion surrounding region B. The principal surface has a plane orientation, and in region B, is mirror-surface-finished. Region B occupies most of the principal surface of this Si single crystal substrate, and a semiconductor device is manufactured therein. Region C (surface-roughened portion) has a plane orientation as with region B, however, region B is mirror-surface-finished, whereas region C is surface-roughened.