Gate oxides prepared by repeated rapid thermal annealings of the thermal oxide in N2O ambient is proposed and metal-oxide-semiconductor (MOS) capacitors with these newly proposed gate dielectrics are studied. It is found that both the charge-to-breakdown and the oxide breakdown field shift to higher values as the number of repeated annealings and the annealing time increase. All the samples that have been subjected to repeated N2O rapid thermal annealings exhibit improved Fowler-Nordheim constant current stress resistance and radiation hardness when compared to the fresh sample and the conventional one-time N2O-annealed sample with a comparable annealing time. It is believed that this multiple N2O annealing method can be another promising candidate for fabricating hot-carrier resistant and radiation-hard MOS devices.