Patent ID: 8748982

Claim:
A high breakdown voltage semiconductor device comprising: parallel pn layers that serve as drift layers and include first-conductivity-type semiconductor regions and second-conductivity-type semiconductor regions which have a longitudinal shape in a direction perpendicular to one main surface of a semiconductor substrate that is a first conductivity-type and has high impurity concentration, and are alternately adjacent to each other in a direction parallel to the main surface of the semiconductor substrate, wherein a current flows through the parallel pn layer in an on-state and the parallel pn layer is depleted in an off-state to sustain a high voltage, the parallel pn layers include first parallel pn layers that are provided in an active region serving as a main current path and second parallel pn layers that are provided in a edge termination region surrounding the active region, the number of pitches between the first-conductivity-type semiconductor region and the second-conductivity-type semiconductor region adjacent to each other in the active region is an even number; a pitch between the first-conductivity-type semiconductor region and the second-conductivity-type semiconductor region adjacent to each other in the second parallel pn layer is two thirds of a pitch between the first-conductivity-type semiconductor region and the second-conductivity-type semiconductor region adjacent to each other in the first parallel pn layer, and a boundary between the first parallel pn layer and the second parallel pn layer at four corners of the semiconductor substrate which has a rectangular shape in a plan view faces two adjacent ends of the first parallel pn layers and three adjacent ends of the second parallel pn layers.