Patent ID: 8748979

Claim:
A semiconductor device, comprising: a semiconductor substrate whose surface is designated as a first plane; a groove part provided on the first plane side of the semiconductor substrate; a source region of a first conductivity type that faces a second plane that is one of side faces of the groove part and at least a part of which extends in a direction parallel to a nodal line of the first plane and the second plane; a drift region of the first conductivity type that faces a third plane being the other side face of the groove part opposite to the second plane, at least a part of which is provided extending in a direction parallel to a nodal line of the first plane and the third plane, and whose concentration is lower than that of the source region; a drain region of the first conductivity type that is placed on the other side of the drift region opposite to the groove part and is provided to touch the drift region, and whose concentration is higher than the drift region; a channel region that is provided over the semiconductor substrate and is sandwiched by the source region and the drift region in a plan view; a first gate insulating layer provided so as to touch a fourth plane that is a plane lying in a direction that intersects the second plane and the third plane among the side faces of the groove part and so as to touch at least the channel region over the first plane, and a gate electrode provided over the first gate insulating layer, wherein the groove part is formed more deeply than the drift region.