Semiconductor device

A semiconductor device includes a semiconductor substrate of a first conductivity type, a body region of the first conductivity type, a source region of a second conductivity type, a drain region of the second conductivity type, a gate electrode, a drift region of the second conductivity type, an implanted oxide layer, and a semiconductor region of the first conductivity type. The semiconductor region is formed to extend in a direction along the top face of the semiconductor substrate. A first distance and a second distance are set so that an intensity of 0.35 MV/cm or less is observed in an electric field of a first region including the end portion of the drift region and in an electric field of a second region between the end of the semiconductor region and the drain region.