Using laboratory X-ray and cobalt-60 irradiations to predict CMOS device response in strategic and space environments

The postirradiation response of CMOS transistors with 30-60-nm gate oxides is investigated as a function of radiation energy, total dose, dose rate, and annealing time. Measurements of threshold voltage, oxide-trapped charge, and interface traps are reported for times ranging from 10 ms to 4 months following LINAC, Co-60, Cs-137, and 10-keV X-ray irradiations. Exposure dose rates vary by 11 orders of magnitude: from 0.05 to 6*10/sup 9/ rad(SiO/sub 2/)/s. To within the +or-10% uncertainty in the overall dosimetry, no 'true' dose-rate effects on MOS device response are observed. Interface trap and oxide-trapped charge densities are linear with total dose. Preliminary recommendations are made for lot acceptance testing of hardened CMOS circuits and devices intended for use in space and strategic environments.>