Patent ID: 8232593

Claim:
A power semiconductor device comprising: a first semiconductor layer of a first or second conductivity type; a second semiconductor layer of the first conductivity type formed on the first semiconductor layer; a third semiconductor layer of the second conductivity type selectively formed on a surface of the second semiconductor layer; at least one trench formed in a periphery of the third semiconductor layer on the surface of the second semiconductor layer, a depth of a bottom surface of the at least one trench being deeper than a bottom surface of the third semiconductor layer, and shallower than a top surface of the first semiconductor layer, and some or all of the at least one trench being in contact with a side surface of the third semiconductor layer; at least one insulator buried in the at least one trench; a first main electrode electrically connected to the first semiconductor layer; and a second main electrode electrically connected to the third semiconductor layer; wherein the at least one trench is formed so as to have a vortex shape when viewed from above the second semiconductor layer.