Investigation of Radiation Damage in Mosfets Using Bias-Temperature Treatments

Radiation damage in thermally-grown p-channel enhancement mode MOS devices irradiated with 1.5 MeV electrons at various doses and gate potentials was investigated by applying bias-temperature (B-T) treatments. It was found that at negative and small positive gate biases applied during irradiation, electrons are trapped in weakly bound states in the oxide. These trapped electrons may readily be removed from the oxide by B-T treatment. The ratio of electrons trapped in the oxide to the radiation-induced net positive charge has a maximum at about -3V bombardment bias. This region of gate bias also corresponds to the minimum of radiation damage commonly observed in this type of device. At zero bombardment bias a saturation of shallow electron trapping is observed at a dose of 3 - 6 × 1013 e/cm2.