Bonding configurations of nitrogen absorption peak at 960 cm-1 in silicon oxynitride films

We investigated bonding configurations of nitrogen atoms in silicon oxynitride films, resulting in a 960 cm(-1) absorption peak, which is a higher frequency than that for Si3N4 (840 cm(-1)). The 960 cm(-1) peak was observed in the films for which an N 1s x-ray photoemission peak was observed with a binding energy of about 398.6 eV, which has been reported as a binding energy associated with the =Si-N-S= structure. However, the 960 cm(-1) peak was absent in the films for which the N 1s peak was observed at about 397.8 eV, being close to the binding energy associated with the Si-3=N structure. We conclude that the absorption peak at 960 cm(-1) arises from the =Si-N-Si= structure of doubly bonded N atoms with two Si atoms, not affected by any oxygen atoms. (C) 1999 American Institute of Physics. [S0003-6951(99)02602-9].