Patent ID: 8242535

Claim:
A vertical insulated gate bipolar transistor, comprising: a semiconductor substrate in which at least an emitter region, a body region, a drift region, and a collector region are formed; an emitter electrode that is formed on a front face of the semiconductor substrate; and a collector electrode that is formed on a rear face of the semiconductor substrate, wherein the emitter region is of a first conductivity type, is formed in a range adjacent to the front face of the semiconductor substrate, and is in contact with the emitter electrode, the collector region is of a second conductivity type, is formed in a range adjacent to the rear face of the semiconductor substrate, and is in contact with the collector electrode, the drift region is of the first conductivity type, and is in contact with the collector region, the body region is of the second conductivity type, and separates the emitter region and the drift region from each other, the collector region is not formed in at least a portion of an ineffective region that surrounds an effective region where the front face of the semiconductor substrate and the emitter electrode are in contact with each other in a planar view of the semiconductor substrate, and the drift region and the collector electrode are in direct contact with each other in the ineffective region at the portion in which the collector region is not formed, the collector electrode includes a first portion that is in contact with the collector region and a second portion that is in contact with the drift region, and thermal resistance of the second portion is lower than thermal resistance of the first portion.