Patent ID: 7049674

Claim:
A reverse blocking semiconductor device comprising: a drift layer of a first conductivity type: a MOS gate structure including a base layer of a second conductivity type selectively formed in a front surface region of the drift layer, an emitter region of the first conductivity type selectively formed in a surface region of the base layer, a gate insulation film covering a surface area of the base layer between the emitter region and the drift layer, and a gate electrode formed on the gate insulation film; an emitter electrode in contact with both the emitter region and the base layer of the MOS gate structure; an isolation region of the second conductivity type surrounding the MOS gate structure through the drift layer and extending across an entire thickness of the drift layer; a collector layer of the second conductivity type formed on a rear surface of the drift layer and connecting to a rear side of the isolation region; and a collector electrode in contact with the collector layer; wherein a distance W is greater than a thickness d, in which the distance W is a distance from an outermost position of an portion of the emitter electrode, the portion being in contact with the base layer, to an innermost position of the isolation region, and the thickness d is a dimension in a depth direction of the drift layer.