US Patent 7663181 Semiconductor device

A semiconductor device includes a vertical field-effect transistor having a substrate of first conduction type in a substrate base, a drain electrode formed on a first surface of the substrate, an epitaxial layer of first conduction type formed on a second surface of the substrate, a source region of first conduction type formed on the semiconductor base, a source ohmic contact metal film in ohmic contact with the source region, trenches formed from the second surface of the semiconductor base, and a gate region of second conduction type formed along the trenches. The semiconductor device further includes a gate rise metal film in ohmic contact with the draw-out layer of the gate region on the bottom of the trenches and rising to the second surface of the semiconductor base, and a gate draw-out metal film connected to the gate rise metal film from the second surface of the semiconductor base.