Abstract: In a double-gate MOS transistor, a substrate, an insulating layer, and a semiconductor layer are formed or laminated in that order, an opening extending to the insulating layer is formed in the semiconductor layer while leaving an island-shaped region, the island-shaped region including a semiconductor crystal layer having a predetermined length and height and a predetermined shape of horizontal section, the semiconductor crystal layer including P-type or N-type source region, channel region, and drain region, in that order, formed therein, a source electrode, gate electrodes, and a drain electrode are provided in contact with side surfaces of the respective regions, and the gate electrodes are provided in contact with the side surfaces of the channel region.

Abstract: Upstanding thin-film channel regions 5 having different heights are formed between source regions 7 and drain regions 8 of MOS transistors, respectively.

Abstract: It is an object of the present invention to provide a CMOS circuit implemented using four-terminal double-insulated-gate field-effect transistors, in which the problems described above can be overcome. Another object of the present invention is to reduce power consumption in a circuit unit that is in an idle state or ready state, i.e., to reduce static power consumption. The two gate electrodes of a P-type four-terminal double-insulated-gate field-effect transistor are electrically connected to each other and are electrically connected to one of the gate electrodes of an N-type four-terminal double-insulated-gate field-effect transistor, whereby an input terminal of a CMOS circuit is formed, and a threshold voltage of the N-type four-terminal double-insulated-gate field-effect transistor is controlled by controlling a potential of the other gate of the N-type four-terminal double-insulated-gate field-effect transistor.