Charge trapping and interface trap creation phenomena observed in 8 nm thick thermally grown oxides and oxides nitrided by low pressure ammonia plasma are reported. These phenomena are observed for samples subjected to uniform high-field current injection. It is demonstrated that trap creation is limited to the generation of interface states. No electron trapping and no positive charge generation are observed for injected fluences ranging from 10−6 − 102 C/cm2 at oxide fields in the range 8–11 MV/cm. Quite similar trap creation rates and kinetics are observed in both samples, which demonstrates the good reliability performance of the nitrided oxide. Results are discussed in terms of impact ionization and trap creation by hydrogen-related species models.