Abstract: A silicon carbide semiconductor device includes: a trench formed on an upper surface of a silicon carbide semiconductor substrate; a gate electrode in the trench; an n-type drift layer, a p-type guard region, an n-type semiconductor region to which a source potential is applied, a p-type body layer and an n-type current diffusion region that have a lower impurity concentration than that of the guard region, the n-type drift layer, the p-type guard region, the n-type semiconductor region, the p-type body layer, and the n-type current diffusion region being formed in the silicon carbide semiconductor substrate; and an n-type JFET region that is formed in the silicon carbide semiconductor substrate so as to be separated from the trench and that connects the current diffusion region and the drift layer. The semiconductor region is separated from the drift layer, the current diffusion region, and the JFET region.

Abstract: In the present invention, in a FinFET having a channel forming region on a surface of a fin that is a semiconductor layer protruding on an upper surface of a substrate, a channel at a corner of the fin is prevented from becoming an ON state with a low voltage and a steep ON/OFF operation is made possible. As a means thereof, in a MOSFET that has a plurality of trenches, each of which have embedded therein a gate electrode, on an upper surface of an n-type epitaxial substrate provided with a drain region on a bottom surface and that has a channel region formed on a surface of a fin which is a protrusion part between the trenches adjacent to each other, a p-type body layer that constitutes a lateral surface of the fin, and a p+-type semiconductor region that constitutes a corner which is an end of the upper surface of the fin, are formed.