Patent ID: 8158490

Claim:
A method for producing a Group III nitride-based compound semiconductor device in which a hetero-substrate is used as an epitaxial growth substrate, said method comprising: stacking an epitaxial layer of a Group III nitride-based compound semiconductor on the epitaxial growth substrate; bonding a support substrate to a top surface of the epitaxial layer via a conductive layer; removing the epitaxial growth substrate by a laser lift-off; and before bonding the support substrate to the epitaxial layer formed on the epitaxial growth substrate, forming trenches in such a manner as to extend from a top surface of a stacked structure including the epitaxial layer formed on the epitaxial growth substrate to at least an interface between the epitaxial growth substrate and a bottom surface of the epitaxial layer, wherein the trenches are formed in at least three lines and divide the epitaxial layer formed on the epitaxial growth substrate into expanded device areas which encompass respective product device structures, and stress relaxation areas, and wherein a plurality of laser irradiations are performed for the laser lift-off such that, after each laser irradiation, the expanded device areas and the stress relaxation areas are separated into a laser-irradiated area and a laser-unirradiated area, and a strip-shaped laser-unirradiated stress relaxation area is formed at a boundary between the laser-irradiated area and the laser-unirradiated area.