US Patent 7385250 Semiconductor device

A semiconductor device comprises a semiconductor portion including first semiconductor layers of a first conduction type and second semiconductor layers of a second conduction type alternately arranged on the surface of a semiconductor substrate to form a striped shape. A main region is formed to arrange a main cell in a well. A current sense cell is arranged in a sense well. A sense region is formed having the direction of the length in a direction that intersects the direction of alternate arrangement of the first semiconductor layers and the second semiconductor layers.