Proton radiation tolerance of SiGe power HBTs

The effects of proton irradiation on the RF power performance of SiGe heterojunction bipolar transistors (HBTs) are, for the first time, reported in this work. Besides linearity measurements, on-wafer large-signal high-power performance was characterized by load-pull measurements for both pre- and post-radiation devices. In addition to dc, small-signal ac and linearity performance, the RF power performance of SiGe HBTs also exhibits excellent tolerance to high-fluence proton radiation. Interestingly, post-radiation devices show minor improvement in linearity. For power performance, only a minor degradation was observed for post-radiation devices under large-signal operation at 4 GHz.