Radiation effects in low-pressure reoxidized nitrided oxide gate dielectrics

Nitridation of the gate oxide is known to improve the radiation resistance of metal-oxide-semiconductor devices on silicon. However, it has generally been found that high-temperature, long-time anneals are required to produce the hardest dielectrics. We report results of 1–5 Mrad (Si) total dose radiation testing of thin gate oxides which have received relatively light nitridations, followed by a reoxidation step. These devices exhibit substantially reduced fixed charge and interface state buildup compared with oxide, and appear to be harder than the more heavily nitrided oxides previously reported.