Dielectric properties of Ti, TiO2 and TiN from 1.5 to 60 eV determined by reflection electron energy loss spectroscopy (REELS) and ellipsometry

The dielectric properties of metallic Ti and thin films of TiO2 and TiN in the energy range from 1.5 to 60 eV have been determined by quantitative ana lysis of the respective electron energy loss spectra in the reflection mode (REELS). The energy loss function (ELF) of every material, that is proport ional to Im {1/epsilon}, is obtained by trial and error until a good quanti tative agreement between the simulated and experimental inelastic electron scattering cross-sections at three different primary electron energies (i.e . 0.5, 1 and 1.5 keV) is achieved. Kramers-Kronig transformation is then us ed to obtain real and imaginary parts of the dielectric function epsilon(om ega). In addition, spectroscopic ellipsometry was used to improve the ELF i n the 1.5 to 4.5 eV energy range where it is strongly affected by the exper imental energy resolution and the presence of the elastic peak. The charact eristic differences among the spectra of the particular compounds are discu ssed in terms of different electronic properties.