SiOxNy Films deposited with SiCl4 by remote plasma enhanced CVD

Silicon oxynitride films have been deposited with SiCl4 by remote-plasma en hanced chemical vapor deposition (PECVD) at a substrate temperature of 250 degrees C. Different mixtures of O-2 and NH3 were used to obtain different oxynitride compositions ranging from SiO2 to an stoichiometry close to that of silicon nitride. Rutherford backscattering spectrometry was used to det ermine the chemical composition of the SiOxNy films. The behavior of the IR absorption spectra as well as the refractive index measured by ellipsometr y were used to estimate the effect of the different deposition parameters. It was found that the IR spectra show a shift of the characteristic peak as sociated with the stretching vibration mode of the Si-O-Si bonds towards lo wer wavenumbers as the relative concentration of ammonia was increased with respect oxygen. No double peaks associated with silicon oxide and silicon nitride were observed, indicating the formation of an homogeneous alloy. Th e IR spectra did not show any presence of water or hydrogen related impurit ies in the film. Also the effect of a hydrogen flow added during the deposi tion process on the structural characteristics of the deposited films was s tudied using dielectric spectroscopy and atomic force microscopy measuremen ts showing that the hydrogen flow added during deposition results in a redu ction of the film roughness and a planarization effect, which is very inter esting for the application of these films in microelectronics devices. (C) 1999 Kluwer Academic Publishers.