DC, RF, AND NOISE CHARACTERISTICS OF CARBON-DOPED BASE INP/INGAAS HETEROJUNCTION BIPOLAR-TRANSISTORS

The first successful demonstration of high-performance InP/InGaAs heterojunction bipolar transistors utilizing a highly carbon-doped base is reported. The detailed device characteristics including dc, RF, and noise performance have been investigated. For the first time base layers free of hydrogen passivation have been obtained using chemical beam epitaxy. The HBT's showed almost ideal de characteristics; a gain independent of collector current, a near unity ideality factor, a very small offset-voltage, and a high breakdown voltage. Devices having two 1.5 mu m x 15 mu m emitter fingers exhibited a maximum fT of 115 GBz and f(max) of 52 GHz. The device also exhibited a minimum noise figure of 3.6 dB and associated gain of 13.2 dB at a collector current level of 2 mA where a fT of 29 GHz and f(max) of 23 GHz were measured. The nearly ideal dc characteristics, excellent speed performance, and RF noise performance demonstrate the great potential of the carbon-doped base InP/InGaAs HBT's.