Annealing of Total Dose Damage in the Z8OA Microprocessor

Very large annealing rates have been observed for total dose damage in a commercial microprocessor. The annealing behavior has a complex dependence on bias conditions and dose rate, and persists for time periods in excess of 106 s. With positive bias applied, super recovery of the gate threshold voltage occurs so that the voltage shift at long times is opposite to that observed at short times after irradiation. These effects can cause large errors in total dose testing, and need to be carefully considered when planning tests on LSI devices.