METHOD OF SURFACE TREATMENT OF GROUP III NITRIDE CRYSTAL FILM, GROUP III NITRIDE CRYSTAL SUBSTRATE, GROUP III NITRIDE CRYSTAL SUBSTRATE WITH EPITAXIAL LAYER, AND SEMICONDUCTOR DEVICE

摘要

A method of surface treatment of a Group III nitride crystal film includes polishing a surface of the Group III nitride crystal film, wherein a pH value x and an oxidation-reduction potential value y (mV) of a polishing liquid used for the polishing satisfy both relationships of y≧−50x+1,000 and y≦̸−50x+1,900.