Semiconductor device and method for manufacturing the same

A semiconductor device including a trench gate type field effect transistor and a diode which are formed in a semiconductor substrate, the semiconductor device comprising:

• a first trench and a second trench which are formed in the semiconductor substrate;
• a gate electrode of the trench gate type field effect transistor, the gate electrode being formed in the first trench through a gate insulating film;
• a conductive material formed in the second trench through a first insulating film;
• and
• a first semiconductor region of a first conductivity type and a second semiconductor region of a second conductivity type opposite to the first conductivity type which are used for the diode and formed in the semiconductor substrate,
• wherein the second trench is formed so as to surround the second semiconductor region in a planar view,
• wherein a part of the first semiconductor region is formed directly below the second semiconductor region,
• wherein a PN junction is formed between the second semiconductor region and the part of the first semiconductor region located directly below the second semiconductor region, and thereby the diode is formed, and
• wherein the conductive material is electrically coupled to one of the first semiconductor region and the second semiconductor region.