The reliability of SiGe HBT under swift heavy ion irradiation

Silicon-germanium (SiGe) heterojunction bipolar transistors (HBTs) were irradiated by 25Mev Si
⁴⁺
ion with equivalent absorbed dose from 300 krad(Si) to 10 Mrad(Si). Pre- and post-irradiation direct current (DC) characteristics were used to quantify the dose tolerance to the heavy ion irradiation. Base current was found more sensitive than collector current and current gain appeared to decline with the ion fluence increasing. An unexpected increase in emitter current was observed in the reversed-mode operation. The reverse leakage current of base-collector and base-emitter junction increased with the increase in ion fluence. The displacement damages were thought to be mainly contributed to performance degradation of SiGe HBT.