Patent ID: 9059236
Filing Date: 2015-06-16
Classification: H01L

Abstract:
1. A semiconductor device comprising: a first electrode; a second electrode; a first semiconductor layer of a first conductivity type provided between the first electrode and the second electrode; a second semiconductor layer of the first conductivity type provided between the first semiconductor layer and the second electrode, and the second semiconductor layer having a lower impurity concentration than the first semiconductor layer; a first semiconductor region of a second conductivity type provided between part of the second semiconductor layer and the second electrode; a second semiconductor region of the second conductivity type provided between a portion different from the part of the second semiconductor layer and the second electrode, and the second semiconductor region being in contact with the first semiconductor region; and a third semiconductor region of the second conductivity type provided between at least part of the first semiconductor region and the second electrode, impurity concentration of the third semiconductor region at a surface in contact with the second electrode in the third semiconductor region being higher than impurity concentration of the first semiconductor region at a surface in contact with the second electrode in the first semiconductor region and impurity concentration of the second semiconductor region at a surface in contact with the second electrode in the second semiconductor region, and thickness of the second semiconductor layer sandwiched between the first semiconductor region and the first semiconductor layer being thinner than thickness of the second semiconductor layer sandwiched between the second semiconductor region and the first semiconductor layer.