Temperature Dependence of Annealing of Gamma-Ray Radiation Damage on SOS Transistors

The temperature dependence of annealing without bias of gamma irradiation damage on n-channel SOS transistors has been studied. It was observed that the interface state charge increase occurred by isothermal annealing when more oxide trapped charge than interface state charge was created by way of irradiation. The cause of building up of interface state charge is the conversion from oxide trapped charge into interface state charge. The rate limiting step of threshold voltage annealing is this conversion step. When the interface state charge is created outstandingly by irradiation, the radiation-induced interface state charge is instantly annealed at high temperature. The conversion from oxide trapped charge into interface state charge was also observed. Therefore, the characteristics of annealing of interface state become complicated at high temperature. The instability of threshold voltage after the irradiation is owing to the fluctuation of interface state.