Abstract: A method of manufacturing a MOS device wherein a semiconductor substrate is selectively etched to form a groove in a field region and an element formation region surrounded by the groove such that an angle .theta. is formed between a wall of the groove and a first imaginary extension of a top surface of the element formation region, the angle .theta. satisfying the relation, 70.degree..ltoreq..theta..ltoreq.90.degree.. Then, a field insulating film is deposited in the groove, and a MOS transistor is formed in the element formation region. The element formation region has source, drain and channel regions of a field effect transistor therein and a gate electrode formed on a gate insulating film on the channel region. The gate electrode extends onto the surface portion of the field insulating film.

Abstract: A voltage-control type semiconductor switching device is disclosed which includes a pair of controlled electrodes to which a control voltage signal is supplied, and a semiconductive layer formed between the electrodes so as electrically insulative from the electrodes through insulative layers. The semiconductive layer has a channel region and a carrier-storage region which is substantially nonconductive. The channel region is formed laterally along the longitudinal direction of the electrodes, thereby allowing majority carriers such as electrons of the semiconductive layer to flow in the lateral direction. In the current cut-off mode, the carrier-storage region temporarily stores the carriers which move in the direction of thickness of the semiconductive layer due to the electric field created by the voltage. In the current conduction mode, the carrier-storage region releases the carriers stored therein toward the channel region.