Patent ID: 10868123

Abstract:
The object of the present invention is to increase the breakdown voltage without thickening an SOI layer in a wafer-bonded dielectric isolated structure. A device region of a SiC-SOI device includes: a first trench continuously or intermittently surrounding an n− type drift region and not penetrating a SiC substrate; an n+ type side surface diffusion region formed on each side surface of the first trench; an n+ type bottom diffusion region formed under the n− type drift region and in contact with the n+ type side surface diffusion region; and a plurality of thin insulating films formed in proximity to a surface of the n− type drift region at regular spacings of 0.4 μm or less. A surrounding region includes a second trench formed to continuously surround the first trench and penetrating the SiC substrate, and an isolated insulating film region formed on each side surface of the second trench.