Patent ID: 9166038
Filing Date: 2015-10-20
Classification: H01L

Abstract:
1. A semiconductor device comprising: a semiconductor layer having a first face provided with a trench and a second face opposite to the first face; a gate electrode provided in the trench; and an insulating layer provided in the trench so as to insulate the semiconductor layer and the gate electrode from each other; wherein the semiconductor layer includes a first semiconductor layer of a first conductivity type, and a second semiconductor layer of a second conductivity type opposite to the first conductivity type, wherein the trench is formed so as to penetrate through the second semiconductor layer and to reach the first semiconductor layer, wherein the second semiconductor layer includes a close portion closer to the second face of the semiconductor layer than the trench is, while also including a sublayer disposed farther from the second face of the semiconductor layer than the close portion is, and impurity concentration in the close portion is greater than impurity concentration in the sublayer so as to suppress a depletion layer in the close portion, wherein a recessed portion is provided at the first semiconductor layer or the second semiconductor layer, wherein the close portion and the recessed portion are disposed so as to overlap in a widthwise direction perpendicular to a depthwise direction of the trench, wherein the second semiconductor layer includes a channel region formed along the trench and in contact with the first semiconductor layer, wherein the sublayer is smaller in size measured in the depthwise direction of the trench than the close portion, and wherein the recessed portion is smaller in size measured in the depthwise direction of the trench than the trench.