Document Type and Number:
Japanese Patent JP3088815
PURPOSE: To provide a phototransistor having a good CMR characteristic, wherein no malfunction is generated by a displacement current when using it as the photodetector of a photocoupler.
CONSTITUTION: In a phototransistor, first and second guard ring layers 9, 25 are provided along respective P-N junction parts 30, 35 of input stage and output stage transistors TR1, TR2, and the guard ring layers 9, 25 are connected electrically with an emitter electrode 24 of the output stage transistor TR2. Further, an emitter electrode 21 of the input stage transistor TR1 and a base electrode 23 of the output stage transistor TR2 are connected by a wiring layer 22 provided above the guard ring layers 9, 25 via an insulation layer.
July 14, 2000
January 07, 1992
H01L31/10; H01L31/12; (IPC1-7): H01L31/10