Semiconductor device, a method of manufacturing the same, and a semiconductor device protective circuit

Abstract

A Schottky diode which provides a structure having no P-N junction while improving voltage resistance against a reverse bias when employed in combination with an insulated gate semiconductor device in particular. In order to attain the aforementioned object, a P-type impurity region having a surface exposed on a surface of an N-type semiconductor substrate functioning as a drain for functioning as a channel region and a gate insulator film covering it are provided. A gate electrode is extended from above the gate insulator film over a first taper of an oxide film. In a Schottky diode rendering the semiconductor substrate a cathode and having a boundary layer as a Schottky region, on the other hand, an anode electrode is extended from above the boundary layer over a second taper of the oxide film existing above an end portion of the boundary layer.