Semiconductor device and method of fabricating the same

摘要

A semiconductor device comprises a first conductivity type semiconductor layer and a second conductivity type well region which is formed on the semiconductor layer. The well region includes a first semiconductor region of a first depth and a second semiconductor region of a second depth deeper than the first depth which is provided in the central portion of the first semiconductor region. The ratio of the first depth to the second depth is settled in a range from 0.85 to 0.95 in order to increase the breakdown voltage of the semiconductor device.