| 摘要 |
PROBLEM TO BE SOLVED: To provide an inexpensive bidirectional photothyristor chip that can directly control load with stable commutation characteristics and can be produced in a good yield with high efficiency.SOLUTION: A bidirectional photothyristor chip includes a pair of photothyristor parts (9, 10) each including: a first diffusion layer (12) of a second conductivity type formed on a surface of a substrate (11) of a first conductivity type; a second diffusion layer (13) of a second conductivity type formed on a surface of the substrate (11) of the first conductivity type opposite the first diffusion layer (12); and a third diffusion layer (14) of the first conductivity type formed in the second diffusion layer (13) opposite the first diffusion layer (12). The substrate (11) of the first conductivity type has its thickness set so that hold currents of the photothyristor parts (9, 10) based upon current amplification factors of PNP transistors and current amplification factors of NPN transistors constituting PNPN parts as the photothyristor parts (9, 10) reach a target value. |
