The breakdown andC–Vcharacteristics of SiO2films treated in either N2or NH3atmospheres at different temperatures have been investigated. The Auger electron spectroscopy profiles of the samples treated in a N2atmosphere at 1200 °C indicate that the nitrogen is preferentially incorporated into the Si/SiO2interface, thus increasing both the dielectric breakdown and the positive spatial charge associated with the interface. A similar increase of the dielectric breakdown is observed in the NH3treated samples, although in this case the nitrogen is found across the whole oxide thickness.