Total Dose Effects at Low Dose Rates

The effects of irradiation at very low dose rates are discussed for hardened CMOS devices from two different manufacturers. For some devices, rate effects were important even at dose rates of 0.04 rad(Si)/s, so that even lower dose rates may be required to characterize their behavior for some applications. Modeling approaches for low dose rates are discussed, and linearity of the charge generation processes is shown to be an important factor in modeling. Interface state generation for one process was highly nonlinear, which reduced the impact of annealing and super recovery on device hardness.