Abstract: There are provided a processing method for a wide-bandgap semiconductor substrate and an apparatus therefor that use no abrasives or no abrasive grains, or no solution having a large environmental burden at all, can process a single crystal, which is SiC, GaN, AlGaN, or AlN, at a variety of processing speed, can obtain a surface of higher quality than the quality of a surface finished by CMP, and also have an excellent compatibility with a clean room. A catalytic substance having a function of promoting the direct hydrolysis of a work piece (5) or promoting the hydrolysis of an oxide film on the surface of the work piece is used as a processing reference plane (3). In the presence of water (1), the work piece is brought into contact with or extremely close to the processing reference plane at a predetermined pressure.

Abstract: There are provided a processing method for a wide-bandgap semiconductor substrate and an apparatus therefor that use no abrasives or no abrasive grains, or no solution having a large environmental burden at all, can process a single crystal, which is SiC, GaN, AlGaN, or AlN, at a variety of processing speed, can obtain a surface of higher quality than the quality of a surface finished by CMP, and also have an excellent compatibility with a clean room. A catalytic substance having a function of promoting the direct hydrolysis of a work piece (5) or promoting the hydrolysis of an oxide film on the surface of the work piece is used as a processing reference plane (3). In the presence of water (1), the work piece is brought into contact with or extremely close to the processing reference plane at a predetermined pressure.