The effects of proton irradiation on the RF performance of SiGe HBTs

The effects of proton irradiation on the RF performance of SiGe Heterojunction Bipolar Transistors (HBTs) are reported in this paper. Frequency response and broadband noise properties are investigated in SiGe HBTs for proton fluences up to 5/spl times/10/sup 13/ p/cm/sup 2/. The current gain in the radio frequency (RF) bias region and the cutoff frequency (f/sub T/) show little degradation at even extreme proton fluence (realistic space fluences are 1-5/spl times/10/sup 11/ p/cm/sup 2/). The slight degradation of NF/sub min/ is due to the irradiation-induced increase in the total emitter and base resistance. The associated available gain G/sub A, assoc/ at noise matching is 20.2 dB at f=2 GHz and I/sub C/=2.6 mA for a proton fluence of 5/spl times/10/sup 13/ p/cm/sup 2/. These results suggest that space-borne RF circuit applications of SiGe HBTs should be robust to proton irradiation.