Semiconductor device and method of manufacturing semiconductor device

Abstract

A diode formed by a polysilicon layer is disposed between a field oxide film and an interlayer insulating film, in a semiconductor substrate, at a front surface of the semiconductor substrate. One resist mask is used to form contact holes of the interlayer insulating film and contact trenches and a p-type region of the polysilicon layer. The contact trenches are continuously formed from bottoms of the contact holes, respectively, in a depth direction. A low-resistance contact between the p-type region and an anode electrode is formed at least at a bottom of the contact trench. During the formation of the p-type region, while a p-type impurity is ion-implanted in an inner wall of the contact trench, an n-type cathode region maintains an n-type conductivity thereof and a contact with a cathode electrode is formed at sidewalls of the contact trench.