Abstract: A MOS control diode is provided for power switching. In the MOS control diode, a switching speed is high and a reverse leakage current characteristic is improved without additionally needing processes for improving reverse recovery time by converting a power MOSFET which is a majority carrier device to diode having two terminals. Such a MOS control diode can be achieved by forming a discontinuous area in a gate oxide film formed on the surface of a semiconductor substrate so that the conductive gate electrode is connected to the semiconductor substrate. Also, it is possible to form a trench in the semiconductor substrate, to form the gate oxide films on the sidewall of a trench, and to connect the gate electrode to the semiconductor substrate through the bottom of the trench.