Patent ID: 7423298

Claim:
A bidirectional photothyristor chip being one semiconductor chip, comprising: a substrate of a first conductive type; a pair of photothyristor sections each of which is provided on a surface of the substrate of the first conductive type and each of which includes a first diffusion layer of a second conductive type, a second diffusion layer of the second conductive type and a third diffusion layer of the first conductive type formed in the second diffusion layer, wherein one of the pair of the photothyristor sections is disposed on one side of the semiconductor chip while the other of the pair of the photothyristor sections is disposed on the other side of the semiconductor chip; the first diffusion layer constituting part of the one photothyristor section is opposed to the second diffusion layer and the third diffusion layer constituting part of the other photothyristor section; the first diffusion layer constituting part of the other photothyristor section is opposed to the second diffusion layer and the third diffusion layer constituting part of the one photothyristor section; two separate carrier channels are provided between the first diffusion layers and the second diffusion layers of the photothyristor sections respectively; and a carrier movement suppression region for suppressing carriers from moving is formed between two of the second diffusion layers, and wherein the first conductive type is one out of N type and P type; the second conductive type is the other out of N type and P type; in each of the photothyristor sections, a gate resistance and a switching element are connected in parallel in between a base and an emitter electrode of an NPN transistor made up of the third diffusion layer, the second diffusion layer and the substrate, or the first diffusion layer, the substrate and the second diffusion layer; and a control terminal of the switching element is connected to a base of the PNP transistor made up of the third diffusion layer, the second diffusion layer and the substrate, or the first diffusion layer, the substrate and the second diffusion layer.