Patent ID: 9337283
Filing Date: 2016-05-10
CPC Classification: H01L

Claim Text:
1. A semiconductor device comprising: a first semiconductor layer of a first conductivity type; a second semiconductor layer of a second conductivity type formed on the first semiconductor layer; a first electrode extending along a first direction into the first semiconductor layer, the first electrode being surrounded by the first semiconductor layer except at a first end thereof; a first insulation film between the first semiconductor layer and the first electrode, the first insulation film including a first layer contacting the first semiconductor layer and a second layer containing at least one of phosphorus (P) and boron (B) between the first electrode and the first layer, the first insulation film having an increasing thickness along the first direction from the second semiconductor layer to a second end of the first electrode; a second electrode contacting a surface of the second layer of the first insulation film, the second electrode being adjacent to the second semiconductor layer in a second direction crossing the first direction; a second insulation film between the second electrode and the second semiconductor layer and having a thickness that is less than the second thickness of the first insulation film; and a third insulation film between the first electrode and the second electrode.