The check of the elastic scattering model in Monte-Carlo simulation

The coefficient of electron backscattering, the angular and energy distribution of transmitted electrons and of backscattered electrons have been calculated by the Monte-Carlo method using several models of electron elastic scattering. The calculations were carried out for C, Al, Cu, Au, in the 10-100 keV energy range and in the 20-1000 nm film thickness range. Our findings were compared with published experimental results. The cross-section of elastic scattering was calculated either by Rutherford's formula (the screened atomic potential was assumed) or by Mott's theory including electron spin, or was taken from data tables computed from Hartree-Fock atomic wave functions. This provided an opportunity to decide which model of electron-atom elastic interaction is the best for simulation. The results showed that the backscattering coefficient, and mainly its dependence on him thickness and electron energy, is a quantity which is strongly sensitive to the model type. The best agreement between calculated and experimental data was reached, in the full range of primary electron energies and film thicknesses, for Au and Al by using tables with rigorous partial wave calculations and for Cu by using Rutherford's formula, even though the differences among results for Cu are relatively small.