Impact of Proton Radiation on the Large-Signal Power Performance of SiGe Power HBTs

The effects of proton irradiation on the RF power performance of SiGe power HBTs are, for the first time, reported in this work. Large emitter area high-power SiGe HBTs fabricated in a commercial BiCMOS process were irradiated with proton, at fluences up to 2times10¹³ p/cm². Besides DC and small-signal AC characterizations, on-wafer large-signal high-power performance was characterized by load-pull measurements for pre- and post-radiation devices. It is shown that, in addition to DC and small-signal AC performance, the power performance of SiGe power HBTs also exhibits excellent tolerance to high-fluence proton radiations. Only a minor degradation (from the worst measurement case, 0.7 dB degradation in power gain, 8% degradation in PAE) was measured for post-radiation devices under class-AB bias at 1.9 GHz. Moreover, the source and load impedance matching points tuned for the optimum power performance of the devices, which are critical in the design of power amplifiers, are also shown to be robust to proton radiation. This work demonstrates the potential of SiGe power HBTs in the applications of power amplifiers for wireless application under severe radiation environment even without any intentional radiation hardening