Semiconductor wafer, semiconductor device, and methods for fabricating the same

摘要

First, a semiconductor film made of gallium nitride with a thickness of about 5 mum is deposited on a substrate made of sapphire. Subsequently, a surface of the substrate opposite to the semiconductor film is irradiated with, e.g., a third harmonic of a YAG laser with a wavelength of 355 nm. As a result of the laser beam irradiation, the laser beam is absorbed in the region of the semiconductor film adjacent the interface with the substrate and the gallium nitride in contact with the substrate is thermally decomposed by heat resulting from the absorbed laser beam so that a precipitation layer containing metal gallium is formed at the interface between the semiconductor film and the substrate.