MONOLITHICALLY INTEGRATED INGAAS/INP-FE PHOTODIODE-JUNCTION FIELD-EFFECT TRANSISTOR COMBINATION

The chip technology and the properties of a monolithically integrated InGaAs/InP: Fe PD-JFET structure are presented. The JFET with 2 mu m gate length and 190 mu m gate width showed a transconductance of 65 mS/mm and, at a gate voltage of minus 3 V, a gate leakage current of 5 nA. For the PD with a 75 mu m p-layer diameter a dark current of 8 nA at minus 3 V bias and a quantum efficiency of 52% at 1. 3 mu m wavelength were achieved without antireflection coating. For illumination with short light pulses, a photocurrent half-width value of 50 ps was measured. The total input capacitance of the PD-JFET at minus 3 V bias was 0. 58 pF. With a 1 M OMEGA resistor an overall responsivity of 4000 A/W was achieved.