Defect Production in SiO2 by X-Ray and Co-60 Radiations

Hole trapping, interface-state production and annealing were studied in NMOS transistors irradiated with x-rays and Co-60. Hole trapping showed a photon energy dependence that can be explained by existing models. However, interface-state generation showed an energy dependence that cannot be explained using previously available models. The results given here suggest that hole production and trapping in the oxide may involve different mechanisms than the generation of interface states. In addition, annealing of hole trapping observed in what is called "super recovery" or "rebound" was found to be reversible.