Energetics of nitrogen incorporation reaction in SiO2

We study using first-principles calculations the energetics, structural and electronic properties of nitrogen incorporation in SiO2. We consider NO, NH, N2 and atomic N as the nitriding species interacting with a Si-Si bond of an otherwise perfect SiO2 network in order to simulate the nitrogen incorporation near Si/SiO2 interface regions. We find that all the species react with the Si-Si bond forming bridge structures with the Si atoms without dissociating, where NH and atomic N form the most stable structures. Concerning the electronic properties, our results show that the incorporated NH is the only structure which does not introduce trapping center at the interface. The structures involving NO and atomic N are acceptors, whereas that involving N2 may be either a donor or an acceptor. The hydrogen passivation of the electrically active centers is also discussed.