Auger electron emission from a Si(1 1 1) surface during 11-keV Ar+ ion sputtering

Ion sputtering experiments were carried out for a Si(1 1 1)-7 × 7 surface, irradiated with an 11-keV Ar+ beam. The energy spectra of secondary electrons were measured with a cylindrical mirror analyzer (CMA). The dependence of the Auger electron yield on the ion incidence angle, θ, measured from the surface normal, was studied by varying θ from 0° to 80°. The Auger electron yield increases with increasing incidence angle. This angular dependence is similar to that of the Si sputtering yield. Both angular dependences could be reasonably understood in terms of ion range, escape depths of the sputtered ion and the electron mean free path