Method of fabricating power semiconductor device for suppressing substrate recirculation current

Abstract

A power semiconductor device has a first region in which a transistor is formed, a third region in which a control element is formed, and a second region for separating the first region and the third region. The power semiconductor device includes a substrate of a first conductive type and a semiconductor region of a second conductive type arranged on the substrate, and a highly-doped buried layer of the second conductive type and a highly-doped bottom layer of the first conductive type are arranged between the substrate and the semiconductor region, and the first highly-doped bottom layer of the first conductive type is arranged on a top side and a bottom side of the highly-doped buried layer in the first region and extends by a predetermined distance to the second region, and a first isolation region is arranged on the highly-doped bottom layer extending from the first region in the second region, and a highly-doped region of the second conductive type is arranged on the highly-doped buried layer, and a second isolation region is arranged on a second highly-doped bottom layer of the first conductive type . By such structure, parasitic bipolar junction transistors in the first isolation region and the second isolation region can be electrically separated from the third region.