Patent ID: 8878290

Claim:
A semiconductor device comprising: a semiconductor substrate that includes: a body region of a first conductivity type formed in an upper surface of the semiconductor substrate; a drift region of a second conductivity type that is contacted with a lower surface of the body region; a gate electrode that is provided in a gate trench passing through the body region and extending to the drift region and faces the body region; a gate insulator that is provided between the gate electrode and a wall surface of the gate trench and formed with an inverted U-shaped section in a lower surface; and a floating region of the first conductivity type that is enclosed by the inverted U-shaped section and the drift region and in which a lower surface of the floating region is formed under a portion that is located at a lowermost portion in the lower surface of the gate insulator; a first main electrode that is formed on the upper surface of the semiconductor substrate and connected to the body region; and a second main electrode that is formed on a lower surface of the semiconductor substrate.