Atomic and electronic structures of N-incorporated Si oxides

We present first-principles total-energy calculations on the N-incorporated Si oxides, regarded as a replacement for conventional SiO2 in device technology. We investigate the energetics, charge states, and electronic structures for various bond configurations around N. While they remain in the N-incorporated structures, the charge trap states, responsible for leakage current in SiO2, are effectively removed from the energy gap in the H-terminated structures. This shows that improvement in the electrical reliabilities of Si oxynitride films is originated not from N incorporation itself, but from the coexistence of N and H.