| 摘要 |
PURPOSE:To constitute a high speed type photoelectronic integrated circuit, by integrating a hetero-bipolar transistor, which can respond at a high speed, and a PIN photodiode having a light guide layer. CONSTITUTION:A PIN photodiode in a photodetector part is reverse-biased. A depletion layer is expanded in a light absorbing layer 4. Signal light 13, which is inputted into a light guide layer 5 that is held between an emitter layer 2 and a region as a clad layer, i.e., an N-InP layer 7, is propagated toward the light absorbing layer 4 in the light guide layer 5 and absorbed in a depletion layer. Thus electrons and holes are generated. The electrons and the holes become a current in the reverse direction with respect to the PIN junction by an electric field. Said current is supplied from a region of a photodetector part in a base.anode layer 3 into a region in the same base.anode layer 3, which is to become the base of a hetero-bipolar transistor. The current is take out of an emitter electrode 9 and a collector electrode 11 as an amplified signal current. Therefore, a base resistance value becomes low and the junction capacitances between the emitter and the base and between the collector and the base become small. Thus the high speed operation can be carried out. |
