Optical characterization of oxynitride films in the visible-ultraviolet range

Oxynitride optical properties in the visible-ultraviolet spectral range are very interesting, due to their use in electronic device manufacturing. This paper presents spectra of refractive index and extinction coefficient of oxynitride films deposited on silicon with different composition, as derived from spectroscopic ellipsometry measurements on the basis of an effective medium approach. These data evidence the presence of a Si-rich layer on the oxynitride/silicon interface. Electronic polarizability and energy gap of all compounds were evaluated. Moreover, absolute reflectance of the samples was derived from optical functions and compared with the measured value.