Patent ID: 7098506

Claim:
A semiconductor device including a trench-gate MISFET, comprising: a semiconductor body having a first conduction type; a drain region of the trench-gate MISFET having the first conduction type, formed over the semiconductor body; a base region of the trench gate MISFET having a second conduction type which is opposite to the first conduction type, formed over the drain region, a source region of the trench-gate MISFET having the first conduction type, formed over the base region; a trench extending from an upper surface of the source region to the drain region; a gate insulating film of the trench-gate MISFET formed on an inner wall of the trench; a gate electrode of the trench-gate MISFET formed on the gate insulating film; an insulating film formed over the source region and gate electrode, a contact hole formed in the insulating film and exposing the base region and an upper surface and a side surface of the source region; and a source wiring formed in the contact hole and electrically connected with the source region and base region; wherein the contact hole is comprised of a lower portion and an upper portion; the lower portion of the contact hole penetrates the source region and reaches the base region; the lower portion of the contact hole reaches a side surface of the source region; and the upper portion of the contact hole reaches the upper surface of the source region.