Patent ID: 8124984

Claim:
A semiconductor device including a plurality of unit cells formed on an off-cut semiconductor substrate, a principal surface of which is defined by tilting a crystal plane in a predetermined off-cut direction, at least some of the plurality of unit cells each comprising: a first semiconductor layer formed on the principal surface of the off-cut semiconductor substrate; a first conductive region formed on the surface of the first semiconductor layer and having a first conductivity type; a second conductive region formed on the surface of the first semiconductor layer so as to surround the first conductive region and having a second conductivity type that is different from the first conductivity type; a second semiconductor layer formed on the first semiconductor layer with an opening that exposes the first and second conductive regions at least partially; a first conductor located inside the opening of the second semiconductor layer and having a conductive surface that contacts the first and second conductive regions; and a second conductor arranged on the second semiconductor layer and having an opening that exposes the first and second conductive regions at least partially; wherein in a plane parallel to the principal surface of the off-cut semiconductor substrate, the following relationships are satisfied: t y >t x ; and t y −t x >s y −s X where t y represents the absolute value of a difference between the respective lengths of the second semiconductor layer and the second conductor as measured in the off-cut direction; t x represents the absolute value of a difference between the respective lengths of the second semiconductor layer and the second conductor as measured perpendicularly to the off-cut direction; s y represents the absolute value of a difference between the respective lengths of the conductive surface of the first conductor and the opening of the second semiconductor layer as measured in the off-cut direction; and s x represents the absolute value of a difference between the respective lengths of the conductive surface of the first conductor and the opening of the second semiconductor layer as measured perpendicularly to the off-cut direction.