Orientation Dependent LO and TO Phonons Absorption in Silicon Nitride Thin Films Using Infrared Spectroscopy

摘要

In this paper, we report the reflectance spectra of hydrogenated amorphous silicon nitride(a-SiN_x:H) film grown on GaAs substrate using Plasma Enhanced Chemical Vapor Deposition (PECVD) technique. Fourier Transform Infrared (FTIR) spectroscopy has been used explicitly to resolve the LO and TO phonon mode contributions. The results of variable angle polarized IR reflectance on a-SiN_x:H/GaAs samples are obtained for two different orientations. The calculated results for polarized reflectance are in good agreement with experimental measurements by choosing suitable frequencies and damping as fitting parameters.