Patent ID: 8860039

Claim:
A semiconductor device comprising: a semiconductor substrate of a first conductivity type; a drift layer of the first conductivity type formed on a surface of said semiconductor substrate; a plurality of first well regions of a second conductivity type formed selectively in a surface region of said drift layer; a source region of the first conductivity type formed selectively in a surface region of each of said first well regions; a gate electrode formed over said first well regions and said drift layer thereacross through an insulating film; a second well region of the second conductivity type in said drift layer below said gate electrode, and connected to each of said first well regions adjacent to one another; a source electrode connected to said source region; and a drain electrode formed on a rear surface of said semiconductor substrate, wherein a second conductivity type impurity concentration profile of said second well region in a depth direction includes a point which is deeper than said surface region of said drift layer and where a second conductivity type impurity concentration at said point is higher than a second conductivity type impurity concentration at said surface region of said drift layer.