In this paper

we investigate 60Co γ-ray irradiation effects and annealing behaviors of NPN bipolar junction transistors of the same manufacturing technology but different doping concentrations.The transistors of different doping concentrations differ in responses of the radiation effect.More degradation was observed with the transistors of low concentration-doped NPN transistors than the high concentration-doped NPN transistors.The results also demonstrate that reverse-biased transistors are more sensitive to radiation than the forward-biased ones.Mechanisms of the radiation responses are analyzed.