Correlation between Co-60 and X-ray radiation-induced charge buildup in silicon-on-insulator buried oxides

Large differences in charge buildup in SOI buried oxides are observed for X -ray and Co-60 irradiations of SIMOX and Unibond transistors. The Co-60 res ponse is typically worse than the X-ray response. These results are consist ent with expectations derived from previous work on the relative charge yie ld versus held in thick oxides. The effects of bias configuration and subst rate type on charge buildup and hardness assurance issues are explored via experiments and simulation The worst-case bias condition is found to be eit her the off-state or transmission gate configuration. Simulations of the bu ried oxide electric held in the various bias configurations are used to ill ustrate the factors that affect charge transport and trapping in the buried oxides. Hardness assurance implications are discussed.