The dielectric function ˜ε (˜ε = ε1 + iε2) of silicon oxynitride films deposited on silicon wafers by dual ion-beam sputtering is determined by infrared ellipsometry between 580 and 5000 cm−1. The phase-separation model is unable to reproduce the experimental data. The dependence of ˜ε on stoichiometry is analyzed with the microscopic Si-centered tetrahedron model. The random-bonding model with five SiO4−jNj (j = 0–4) tetrahedra gives a good description of the spectra, provided the dielectric function of the mixed tetrahedra is carefully chosen.
© 1996 Optical Society of America
A. Brunet-Bruneau, G. Vuye, J. M. Frigerio, F. Abelνs, J. Rivory, M. Berger, and P. Chaton, "Infrared ellipsometry investigation of SiOxNy thin films on silicon," Appl. Opt. 35, 4998-5004 (1996)