Microwave low-noise AlGaAs/InGaAs HBT's with p/sup +/-regrown base contacts

This paper reports low-noise AlGaAs/InGaAs heterojunction bipolar transistors (HBT's) with p/sup +/-regrown base contacts. To reduce the thermal and shot noises, we have reduced R/sub B/ by using a p/sup +/-regrown base contact and have reduced /spl tau//sub B/ by using a compositionally-graded thin base layer. As a result, F/sub min/ values of 0.9, 1.1, 1.2, and 1.6 dB were obtained at 2, 6, 12, and 18 GHz, respectively. These low-noise characteristics of our HBT's show high potential for low-noise application.