Abstract: The present invention relates to a light-activated semiconductor device comprising light-emitting elements for emitting light respectively, light-receiving elements for producing driving voltages in response to the light respectively and output elements activated in response to the driving voltages respectively. The light-receiving elements are disposed on two planes opposed to each other. The output elements are disposed on their corresponding planes in opposing relationship.

Abstract: A PNPN semiconductor switch including an N type semiconductor substrate, spaced apart first and second P type diffused regions formed on a surface of an N type substrate, spaced apart first and second N type diffused regions formed in the second P type diffused region, a first gate insulating layer formed on the surface of the second P type diffused region between the first and second N type diffused regions to cover portions thereof, a first gate electrode formed on the first gate insulating layer between the first and second N type diffused regions, a resistance region disposed on the first gate insulating layer, one end of the resistance region on the side opposite to the first gate electrode, a second gate insulating layer overlying the first gate electrode and the resistance region, a semiinsulating layer formed on the surface of the substrate except over the first and second P type diffused regions, an insulating layer overlying the semiinsulating layer, a P gate electrode electrically connected to the

Abstract: A circuit for preventing a dV/dt erroneous operation of a PNPN semiconductor switch is replaced by a capacitance on the surface of a semiconductor substrate, a high resistance gate electrode. In other words, such a circuit is formed on the surface of the substrate by a slight modification of the basic design without decreasing the chip area and without isolating component elements.