US Patent 7763893 Silicon carbide semiconductor device

A silicon carbide semiconductor device includes a semiconductor element disposed in a semiconductor substrate having a first conductive type silicon carbide layer and a silicon substrate. The device includes: a trench on the silicon carbide layer to reach the silicon substrate; and a conductive layer in the trench between the silicon carbide layer and the silicon substrate to connect to both of them. The semiconductor element is a vertical type semiconductor element so that current flows on both of a top surface portion and a backside surface portion of the semiconductor substrate. The current flows through the conductive layer.