Based on first-principles theoretical calculations, a very stable N complex was found in oxynitrides, which consisted of two N atoms at O sites and one O vacancy. This N complex was electrically inactive without bonding with H, removing the electrical activity of O vacancies, and the stability of this complex was greatly enhanced as going from pure oxide to oxynitride films. It was suggested that charge traps involving a single N atom, such as a bridging N center, could be deactivated by reactions with O or NO interstitials, and resulting N interstitials were easily depleted into the interface, in good agreement with experiment.

Electrically Inactive Nitrogen Complex in Si Oxynitride. E.C.Lee, K.J.Chang: Physical Review B, 2002, 66[23], 233205 (4pp)