Thin wet oxides have been grown by in situ steam generation technique and nitrided by NO or N2O in a RTP Centura by applied material system after the oxidation. Nitrogen distributions are obtained by SIMS measurements and correlated with the charge trapping characteristics, showing relevant differences with respect to the oxide grown in furnace. The oxide quality is found to be strongly affected by a too high N concentration within the dielectric. On the other hand, the nitrogen concentration effectively stops B diffusion from the poly-Si gate. The very high temperature treatment has a great impact on substrate dopant redistribution influencing the reliability evaluation from constant voltage stress. When properly normalized similar results are obtained for current and voltage stresses. A significantly improved oxide quality is observed for ISSG oxide grown after the nitridation of the native oxide and associated with a more distributed N peak within the oxide, It is then possible to obtain a trade off between B barrier diffusion and high dielectric quality.