Silicon oxynitride thin films have been deposited using remote plasma chemical vapor deposition fromSiCl4+NH3+O2gas mixtures. The stoichiometry of the deposited films varies from that corresponding to the silicon oxide to a stoichiometry very close to silicon nitride when theNH3/O2gas ratio is changed in the plasma. The approximate compositions of the films were determined by Rutherford backscattering spectroscopy and nuclear reaction analysis, and the local bonding arrangements were determined by infrared spectroscopy. Analysis of metal–insulator–semiconductor devices under the effect of and external sinusoidal electric field (dielectric spectrometry) indicates the presence of traps centers in theSi–SiO2interface. Correlations between the local bonded structures in the oxynitride and the conduction and polarization processes detected in the films are also discussed.