Abstract: A silicon carbide semiconductor device includes an electric field relaxation layer disposed in a drift layer. The electric field relaxation layer includes a first region having a second conductivity type and disposed at a position deeper than trenches, and a second region having the second conductivity type and disposed between the adjacent trenches to be away from a side surface of each of the adjacent trenches. Each of the first region and the second region is made of an ion implantation layer. The electric field relaxation layer further includes a double implantation region in which the first region and the second region overlap with each other, and the electric field relaxation layer has a peak of a second conductivity type impurity concentration in the double implantation region.

Abstract: A manufacturing method of a SiC device includes: forming a drift layer on a substrate having an orientation tilted from a predetermined orientation with an offset angle; obliquely implanting a second type impurity with a mask on the drift layer so that a deep layer is formed in the drift layer, wherein the impurity is implanted to cancel the offset angle; forming a base region on the deep layer and the drift layer; implanting a first type impurity on the base region so that a high impurity source region is formed; forming a trench having a bottom shallower than the deep layer on the source region to reach the drift layer; forming a gate electrode in the trench via a gate insulation film; forming a source electrode on the source region and the base region; and forming a drain electrode on the substrate.