Total Ionizing Radiation Effect Of Typical SiGe HBTs

In order to investigate the total ionizing dose radiation response and the latent radiation damage mechanisms of the different SiGe HBTs under different bias conditions and dose rate, we selected the different commercial SiGe HBTs and designed the irradiation experiments. The radiation experiments were performed with the the 60 Co γ rays under the different bias conditions,the SiGe HBTs were irradiated to the total dose of 1.1Mrad(Si) and 1.0 Mrad(Si) under the high dose rate and low dose rate of 80rad(Si)/s and 0.05rad(Si)/s, respectively. The experiments results showed that the SiGe HBTs have a satisfactory performance of anti- radiation to some extent, and the base current and the direct current gain of the devices are more susceptible to ionizing radiation than the collector current. Except the device NESG260234, all the other devices suffered the most radiation degradation under the reverse bias condition of the base-emitter junction, followed by the zero bias and forward condition, thus, the reverse bias condition of the base-collector junction can be seen as the worst irradiation bias. And the potential radiation damage mechanism can explain by the fringe field model. Different dose rate irradiation experiments results showed that to the device KT1151 there have only a Time-Dependent Effect, but to the device KT9041 there have an obvious Enhanced Low Dose Rate Sensitivity, presented as the degradations of parameters under low dose rate are much more higher than that under the high dose rate. And the dose rate effect of NESG260234 and BFP640 ESD is less evident under the analysis of the current data. The different dose rate effects of the device can be contribute to the suppression of the irradiation induced damage under the high dose rate irradiation from the space charge model.