Patent ID: 7999345

Claim:
A semiconductor device including a first region having a Schottky barrier diode formed therein and a second region having a power MISFET formed therein, the first region comprising: (a1) a semiconductor substrate of a first conductivity type having an upper surface and a lower surface on a side opposite to the upper surface; (a2) a first semiconductor layer of the first conductivity type formed over the upper surface of the semiconductor substrate; (a3) a second semiconductor layer of the first conductivity type formed over the first semiconductor layer; (a4) a first metal film formed over the second semiconductor layer, the first metal film and the second semiconductor layer forming a Schottky junction; and (a5) a second metal film formed over the lower surface of the semiconductor substrate, the second region comprising: (b1) the semiconductor substrate; (b2) the first semiconductor layer formed over the semiconductor substrate; (b3) a channel region formed in the first semiconductor layer and having a second conductivity type opposite to the first conductivity type; (b4) a trench penetrating through the channel region and reaching the first semiconductor layer; (b5) a gate insulating film formed over an inner wall of the trench; (b6) a gate electrode formed over the gate insulating film and filled in the trench; (b7) a source region of the first conductivity type contiguous to the trench and formed over the channel region; (b8) the first metal film formed over the source region and electrically coupled to the source region; and (b9) the second metal film formed over the lower surface of the semiconductor substrate, wherein the first metal film functions as an anode electrode of the Schottky barrier diode in the first region and as a source electrode of the power MISFET in the second region, wherein the second metal film functions as a cathode electrode of the Schottky barrier diode in the first region and as a drain electrode of the power MISFET in the second region, wherein the second semiconductor layer has a doping concentration lower than that of the first semiconductor layer, and wherein a boundary between the first semiconductor layer and the second semiconductor layer is formed in a region as deep as the bottom portion of the trench or in a region shallower than the bottom portion of the trench, and wherein the second region further comprises: (b10) a contact hole arranged apart from the trench and having a depth greater than that of the source region; (b11) a body contact region formed below the bottom portion of the contact hole and comprising a semiconductor region of the second conductivity type; and (b12) a first semiconductor region contiguous to the body contact region and comprising a semiconductor region of the second conductivity type formed in a region deeper than the body contact region, and wherein the contact hole is filled with the first metal film.