Total Dose Hardness Assurance for Microcircuits for Space Environment

A hardness assurance procedure is being developed that can be used to predict the degradation of certain CMOS microcircuits in space environment based on the results of total dose testing at high dose rate. The procedure includes heating the device, following irradiation, at specified temperature, time, and bias conditions. The interface state charge density is shown to vary inversely with dose rate. Therefore a correction in device hardness is required for space applications due to the increase in interface state charges at low dose rates. The annealing of oxide and interface state traps follows a first order reaction with an activation energy of 0.2 eV and 0.6 eV respectively.