DIELECTRIC LOSS FUNCTION OF SI AND SIO2 FROM QUANTITATIVE-ANALYSIS OFREELS SPECTRA

A recently proposed model for quantitative analysis of reflection elec tron energy-loss spectra (REELS) has been applied to evaluate the diel ectric loss function of Si and SiO2 in the 4-100 eV energy range, and to determine inelastic scattering properties for these materials for l ow-energy electrons (500-10 000 eV). Appropriate trial energy-loss fun ctions (i.e. Im{1/epsilon}) are used and the best loss function is fou nd from the criterion that a satisfactory quantitative agreement is ob tained between the simulated and experimental inelastic scattering cro ss-sections at several primary electron energies. The fact that the en ergy-loss functions determined in this work agree remarkably well with optical data gives some confidence in the applied procedure. In addit ion, the effective inelastic mean free paths of the electrons as a fun ction of the primary energy and the path travelled inside the medium h ave also been determined in terms of the respective energy-loss functi ons.