Patent ID: 7791134

Claim:
A power semiconductor device, comprising: a first semiconductor layer of a first conductivity type, having a first main surface and a second main surface; a second semiconductor layer of a second conductivity type, provided upon said first semiconductor layer of the first conductivity type; a set of at least two trench gates, each trench gate having a trench provided with an upper portion and a bottom portion, the upper portion extending from the top side of said second semiconductor layer of the second conductivity type and into said first semiconductor layer of the first conductivity type, and the trench bottom portion being disposed within said first semiconductor layer of the first conductivity type, a gate insulation film provided lining the inner surface of the trench, and a gate electrode filling the gate-insulation-film-lined trench, wherein a distance between adjacent trench bottom portions of the at least two trench gates within said first semiconductor layer of the first conductivity type is narrower than a distance between adjacent upper portions of the at least two trench gates, and the adjacent trench bottom portions extend toward each other in a direction that is substantially perpendicular to the direction in which each of the upper portions extend from the top side of the second semiconductor layer of the second conductivity type; a set of first semiconductor regions, of the first conductivity type, each selectively provided in the top side of said second semiconductor layer of the second conductivity type and contiguously bordering on said trench gates; a first main electrode provided upon said second semiconductor layer of the second conductivity type, and electrically connected to said first semiconductor regions of the first conductivity type; a third semiconductor layer of the second conductivity type provided on the second main surface; and a second main electrode provided on said third semiconductor layer of the second conductivity type.