Probabilitistic and deterministic approaches to surface contour evolution during sputtering

A generalised defining equation to describe surface topography evolution during space and time randomised ion impact is developed. This model includes the effects of surface gradient and curvature dependent sputtering, ballistically induced surface atom transport and relaxation effects including diffusion. Numerical methods are required to solve this equation and a simple but illustrative example is given. It is also shown that deterministic or continuum methods, with additional random noise, can serve as a useful approximation and how these can predict evolution of periodic surface structures. (orig.)