Correlation between High Dose Rate Irradiation and Low Dose Rate Irradiation for Switched Dose Rate Technique

Based on gated lateral p-n-p (GLp-n-p) transistors, the correlation between the high dose rate (HDR) and low dose rate (LDR) irradiations during the switched dose rate experiments is investigated. Experimental results show that a significant deviation of the current gain degradation caused by switching dose rate irradiations from that by individual LDR ones is found. It is also observed that, after the switching of dose rate from HDR to LDR, the positive oxide-trapped charges induced by the HDR irradiations would influence the recombination of interface traps produced by the LDR irradiations, leading to an abnormal evolution of the excess base current and excess collector current for the GLp-n-p transistors. The decrease in the positive oxide-trapped charges from HDR to LDR is not caused by an annealing effect. The evolution of positive oxide-trapped charges could influence the formation of interface traps during switched dose rate experiments. All the experimental results indicate that the degradations in the GLp-n-p caused by the HDR and LDR irradiations are not two independent processes for the switched dose rate technique.