Electrically inactive nitrogen complex in Si oxynitride

Abstract

Based on first-principles theoretical calculations, we find a very stable nitrogen complex in oxynitrides, which consists of two N atoms at O sites and one O vacancy. This N complex is electrically inactive without bonding with hydrogen, removing the electrical activity of O vacancies, and the stability of this complex is greatly enhanced as going from pure oxide to oxynitride films. We suggest that charge traps involving a single N atom, such as a bridging N center, can be deactivated by reactions with O or NO interstitials, and resulting N interstitials are easily depleted into the interface, in good agreement with experiments.