The influence of non-uniform incident flux upon surface erosion processes

Abstract

The surface topographic development by sputter erosion of a solid resulting from spatially non-uniform projectile bombardment is considered theoretically. It is shown that whilst formal prediction of time-dependent surface geometry is possible, analytic solution of the defining equations is generally unachievable, although an approximate treatment may be made for the case of a Gaussian flux distribution profile and an initially plane surface. It is shown that profile perturbations resulting from erosion rate-projectile incidence angle variations can assume importance when erosion crater depths become of similar order to projectile beam width. This behaviour is also revealed by computer simulation of the erosion process and a sand blasting experimental analogue study.