Patent ID: 7888733

Claim:
A power semiconductor device, comprising: a first semiconductor layer of a first conductivity type; a second semiconductor layer of a second conductivity type, provided on a top side of the first semiconductor layer; a third semiconductor layer of the second conductivity type, provided on the second semiconductor layer; a fourth semiconductor layer of the first conductivity type, provided on the third semiconductor layer; two trench gates provided parallel and adjacent to each other, and each composed of a trench that extends from a top side of the fourth semiconductor layer, with a trench bottom portion reaching into the third semiconductor layer, a gate insulation film lining the trench, and a gate electrode filling the trench being lined with the gate insulation film, the two trench gates are arranged in close proximity to each other so as to operate as a single gate electrode having a reduced gate resistance; two first semiconductor regions of the second conductivity type, provided contiguously bordering on only one side of each of the two trench gates that operate as the single gate electrode, located at the outer sides not facing each other of each of the two adjacent trench gates, and located in the top side of the fourth semiconductor layer; a first main electrode that is provided on the fourth semiconductor layer and is electrically connected with the first semiconductor region; and a second main electrode provided on a bottom side of the first semiconductor layer; and two dummy trenches, each dummy trench including a trench that extends from the top side of the fourth semiconductor layer with the trench bottom portion reaching into the third semiconductor layer; an insulation film lining the trench; and a dummy electrode that fills the trench being lined with the insulation film and is connected with the first main electrode, wherein a distance between the two dummy trenches that are arranged adjacent to each other is wider than a distance between the two trench gates that are arranged adjacent to each other.