Patent ID: 8084812

Claim:
A semiconductor device comprising: a semiconductor substrate of a second conductivity type; a bidirectional semiconductor device and a control circuit of the bidirectional semiconductor device integrated with the semiconductor substrate, wherein the bidirectional semiconductor device comprises: a well region of a first conductivity type selectively formed on one surface side of the semiconductor substrate, and having a predetermined depth from a surface thereof; a trench located in the well region; a first semiconductor region of the second conductivity type and a second semiconductor region of the second conductivity type located in a surface region of the well region respectively, wherein the first semiconductor region and the second semiconductor region are separated by the trench and the well region and in contact with the trench; a third semiconductor region of the first conductivity type located in a surface region of the first semiconductor region and contacting with the trench; a fourth semiconductor region of the first conductivity type located in a surface region of the second semiconductor region and contacting with the trench; a fifth semiconductor region of the second conductivity type located in a surface region of the first semiconductor region; a sixth semiconductor region of the second conductivity type located in a surface region of the second semiconductor region; a first control electrode located on an insulating film on the first semiconductor region between the well region of a side wall of the trench and the third semiconductor region; a second control electrode located on an insulating film on the second semiconductor region between the well region of a side wall of the trench and the fourth semiconductor region, apart from the first control electrode; a first main electrode contacting with the third semiconductor region and the fifth semiconductor region; a second main electrode contacting with the fourth semiconductor region and the sixth semiconductor region; a first MOSFET in which the well region is a drain and the third semiconductor region is a source; and a second MOSFET in which the well region is a drain and the fourth semiconductor region is a source, wherein the first MOSFET and the second MOSFET are connected to each other in series, and wherein the bidirectional semiconductor device allows electric current to flow between the first main electrode and the second main electrode.