Abstract: A static induction transistor includes a semiconductor substrate with an energy band gap greater than that of silicon, and the semiconductor substrate has a first gate region to which a gate electrode is connected; and a second gate region positioned within a first semiconductor region which becomes a drain region, and the first gate region is in contact with a second semiconductor region which becomes a source region. According to this construction, the OFF characteristics of the static induction transistor are improved.

Abstract: The present semiconductor switching device comprises a silicon carbide single crystal of hexagonal symmetry having a first conductive type and a semiconductor region of a second conductive type opposite to the first conductive type and locating in the silicon carbide single crystal. The silicon carbide single crystal of the first conductive type and the semiconductor region of the seconductive type form a pn junction. The pn junction interface has an interface extended in the depth direction from the surface of the silicon carbide single crystal, and the interface includes a crystal plane in parallel to the <1120> orientation of the silicon carbide single crystal or approximately in parallel thereto, thereby reducing the leak current.