Impact of bias conditions on performance degradation in SiGe HBTs irradiated by 10 MeV Br ion

Effects of bias conditions on 10 MeV Br ion irradiation were investigated in NPN SiGe HBTs. Pre- and post-radiation direct current (DC) characteristics, such as current gain, leakage current, Early voltage and neutral base recombination, were studied and used to quantify the dose tolerance to 10 MeV Br ion. Experiment results for different bias conditions were compared and discussed in detail. It is found that performance degradations are indeed bias dependent. The BE junction reversed-biased mode suffers the largest degradation and the case with BE junction forward-biased shows the smallest degradation. The underlying physical mechanisms are analyzed and investigated in present work. The injection annealing effect of displacement damage is found to be responsible for the different irradiation response of SiGe HBTs under three bias conditions.