A simple model for etching.

A simple numerical model for the etching of materials is described. Atoms along the surface are removed randomly, with probabilities weighted by both the underlying crystal structure and by the bond strength of atoms to their nearest neighbors. Particular attention is paid to the resulting surface morphology, and its possible relationship to a fractal dimensionality. This study is relevant to fundamental questions surrounding the mechanisms of etching, as well as to technologically important issues that arise as the size of the etched features extend below 1000angstroms.