InGaAsP/InP HETERO JUNCTION BIPOLAR TRANSISTOR WITH HIGH CURRENT GAIN.

N-InP emitter, p-InGaAsP base and n-InGaAsP collector hetero junction bipolar transistors (HBT's) were fabricated. It has been show that a maximum current gain of more than 10,000 is obtained with a base carrier concentration of 5 multiplied by 10**1**7 cm** minus **3 and a 0. 15 mu m base width. The current gain decreases notably as the base carrier concentration increases. This behavior is explained by the decrease in emitter efficiency caused by the increase in recombination-gneration current in the emitter-base depletion region.