Patent ID: 8659078

Claim:
A semiconductor device including a power MOSFET and a Schottky barrier diode, comprising: a semiconductor substrate including a first region for the power MOSFET and a second region for the Schottky barrier diode; a first impurity region of a first conductivity type formed in the first region of the semiconductor substrate and constituting a drain region of the power MOSFET; a second impurity region of a second conductivity type opposite to the first conductivity type formed in the first impurity region and constituting a channel region of the power MOSFET; a third impurity region of the first conductivity type formed in the second impurity region and constituting a source region of the power MOSFET; a first trench formed in the first region of the semiconductor substrate such that the first trench penetrates through the third and second impurity regions and such that a bottom of the first trench is located inside the first impurity region; a gate electrode of the power MOSFET embedded in the first trench; a fourth impurity region of the first conductivity type formed in the second region of the semiconductor substrate and constituting a cathode of the Schottky barrier diode; and a first conductive film formed on the fourth impurity region and constituting an anode of the Schottky barrier diode, wherein an impurity concentration of the fourth impurity region is lower than an impurity concentration of the first impurity region, wherein a second trench is formed in the fourth impurity region, wherein a depth of the second trench is shallower than a depth of the first trench, and wherein the first conductive film is formed inside the second trench.