Surface Brillouin scattering in Titanium Carbide films

Abstract

Simulations of surface Brillouin scattering (SBS) spectra of TiC hard films on several substrates have been carried out over a range of film thickness from 5 nm to 1000 nm. The simulations are based on the elastodynamic Green’s function method that predicts the surface displacement amplitudes of acoustic phonons. These simulations provide information essential to understand and analyse experimental data emerging from SBS experiments. A thorough discussion of all possible surface acoustic waves propagating in a TiC film deposited on a substrate is presented. There are striking differences in the simulated SBS spectra depending on the respective elastic properties of the film and the substrate. One can either have stiffening or loading system. This can further be categorised into strong and weak stiffening or loading systems. For the first time the weak stiffening system is presented. The velocity dispersion of the modes as a function of the product of surface wavevector and thickness (q∥d) has also been simulated, which allows the elastic constants of the films to be determined.