Defect generation in non-nitrided and nitrided sputtered gate oxides under post-irradiation Fowler–Nordheim constant current stress

Metal oxide semiconductor (MOS) capacitors were fabricated with nitrided and non-nitrided sputtered oxides. The MOS structures were exposed to 2 Mrad gamma-ray dose and stored in a dry ambient for one year. Post-irradiation stability of MOS capacitors was investigated by applying Fowler–Nordheim constant current stress and monitoring the positive charge, border traps and interface states generation. It was found that nitridation increased the resistance of sputtered oxides to various defects generation under irradiation, electrical and combined radiation–electrical stress. The improved stability is explained in part by compensation of oxygen vacancy defects and Pb centers by nitrogen.

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► Gate oxides were sputtered in Ar/O2 (non-nitrided oxide) and Ar/O2/N2 (nitrided oxide) plasma.
► Reliability of gate oxides was studied after exposure to gamma irradiation and constant current stress.
► It was found that nitrided sputtered oxides have greater immunity to defect generation.
► Hardening of nitrided oxide was related to Pb and E′ centers reduction due to the nitrogen incorporation in SiO2 matrix.