US Patent 11862689 Group-III element nitride semiconductor substrate

Group-III element nitride semiconductor substrate including a first surface and a second surface that are easy to visually distinguish from each other. An end portion is easily detected with an optical sensor, a large effective area (area that can be used in device production) can be secured, and warping of the entirety of the substrate is reduced. A Group-III element nitride semiconductor substrate includes a first surface; and a second surface, wherein the first surface is a mirror surface, the second surface has a second-surface central region and a second-surface outer peripheral region, the second-surface central region is a mirror surface, and the second-surface outer peripheral region is a non-mirror surface.