In this paper, a new technique, namely, the fabrication of NH3-nitrided N2O-annealed oxides (NNO) under reduced pressure, is presented to attain the desired nitrogen concentrations and profiles that eventually improve the hot-carrier lifetime and high immunity to boron penetration. The proposed NNO dielectrics fabricated at reduced pressure (<550 Torr) showed excellent hot-carrier lifetimes and barrier properties to boron penetration without any adverse effects on the electrical properties and reliability.