Effect of surface roughness on EPES and AREPES measurements: Flat and crenels silicon surfaces

EPES (elastic peak electron spectroscopy) and AREPES (angle resolved elastic peak electron spectroscopy) are non destructive methods and very sensitive to the surface region. These techniques allow to measure the percentage η e of elastically backscattered electrons from the surface excited by an electron beam. Both methods are combined with Monte-Carlo (MC) simulations to interpret experimental results. In this work, we underline the importance of a micrometric scale roughness at the surface. The use of an original Monte-Carlo method was fruitful for the simulation, moreover 3D representations have been developed for visualization and qualitative interpretation of the results. For a more precise quantitative study, a 2D representation was necessary. The calculated results have been compared with published experimental ones got for different incidence angles and primary energies, on a silicon surface having triangular saw-tooth aspect (crenels) obtained by photolithography. We have observed that the effect due to the roughness increases with the incidence angle.