Patent ID: 9653595
Date: 2017-05-16
CPC Classifications: H01L

Claim:
1. A semiconductor device comprising: an insulated gate structure that is provided on a first main surface of a first-conductivity-type semiconductor substrate; and a drift layer that is provided between the first main surface of the first-conductivity-type semiconductor substrate and a second main surface opposite to the first main surface, wherein the drift layer is a parallel pn layer including a first-conductivity-type region in which a width in a direction parallel to the first main surface is less than a length in a direction perpendicular to the first main surface and a second-conductivity-type region in which a width in the direction parallel to the first main surface is less than a length in the direction perpendicular to the first main surface, wherein a planar pattern of the drift layer under the insulated gate structure is a stripe pattern, the first-conductivity-type region and the second-conductivity-type region are alternately arranged in the direction parallel to the first main surface so as to come into contact with each other, a pn junction between the first-conductivity-type region and the second-conductivity-type region extends in the direction perpendicular to the first main surface, and a second-conductivity-type second-main-surface-side region having an impurity concentration distribution in which high impurity concentration and low impurity concentration are repeated at a predetermined pitch in the direction parallel to the first main surface, the second-conductivity-type second-main-surface-side region contacting an end of the second-conductivity-type region that is closest to the second main surface, wherein the second-conductivity-type second-main-surface-side region includes: a second-main-surface-side high-concentration region having a higher impurity concentration than the concentration at a bottom of the second-conductivity-type region and a second-main-surface-side low-concentration region having a lower impurity concentration than the concentration at the bottom of the second-conductivity-type region, wherein the second-main-surface-side high-concentration region and the second-main-surface-side low-concentration region are alternately and continuously arranged in a longitudinal direction of the stripe pattern under the insulated gate structure.