ANGULAR-DISTRIBUTION OF ELECTRONS ELASTICALLY BACKSCATTERED FROM SURFACES

The experimentally measured angular distribution of electrons elastically backscattered from polycrystalline or amorphous solids exhibts a strong resemblance to the differential cross-section for single-atom elastic scattering. Consequently most analytical attempts to describe the problem, which involve some simplifying approximations to this scattering cross-section, are inadequate in the modelling of backscattered electrons. The present paper represents an attempt to derive a simple analytical approximation that is able to describe such events. This is done by including the first scattering event exactly and including multiple scattering events using a sort of 'rectilinear + diffusion' theory, which has proved to be successful for modelling the depth distribution function used in Auger and x-ray spectroscopies. For the cases considered (Ag, Al and Cu at 1 kV), the results compare very well with both experimental data and recent Monte Carlo calculations.