Patent ID: 8030704

Claim:
A semiconductor device having a trench gate type MOSFET, comprising: a drain layer of a first conductivity type formed over a main surface of a semiconductor substrate of the first conductivity type; a channel layer of a second conductivity type formed over the drain layer; a first trench formed in the channel layer and the drain layer; an epitaxial layer of the second conductivity type formed in the first trench, an upper surface of the channel layer being higher than an upper surface of the epitaxial layer; a source region of the first conductivity type formed over the channel layer; a second trench formed in the source region, the channel layer, and the drain layer; a gate insulating film formed in the second trench; a gate electrode formed over the gate insulating film; a third trench formed in the source region and the channel layer such that a portion of a side surface of the source region is exposed; and a source electrode electrically contacting the exposed portion of the side surface of the source region.