Patent ID: RE41866

Claim:
A semiconductor device comprising: a first semiconductor layer having a first doping state of a first conductivity type and having first and second major surfaces; a first semiconductor region of a second conductivity type formed selectively in said first major surface of said first semiconductor layer so that said first semiconductor layer is exposed in remains in the first doping state along a peripheral portion of said first major surface , and said first semiconductor layer is exposed in remains in the first doping state in the a form of an insular region in a planar view in a central portion of said first major surface; a second semiconductor region of the first conductivity type formed in a surface of said first semiconductor region, with a channel region provided between said second semiconductor region and said insular region of said first semiconductor layer; a gate insulating film formed on a surface of said channel region; a first gate electrode from a plurality of gate electrodes formed on said gate insulating film; an interlayer insulating film formed at least on said first gate electrode ; a first main electrode formed over a surface of said interlayer insulating film and covering a surface of said second semiconductor region, said first main electrode being electrically connected to said second semiconductor region and having an end extending to a boundary between the peripheral portion of said first major surface and the central portion of said first major surface; a second main electrode formed on said second major surface of said first semiconductor layer; and an integral semi-insulating plasma CVD nitride film covering at least the peripheral portion of said first major surface other than the central portion of said first major surface and not extending to an upper portion of said first gate above any gate electrode , said integral semi-insulating plasma CVD nitride film having a conductivity which does not lose function as an insulating film and stabilizes breakdown voltage characteristics of the semiconductor device.