Huygens' construction for successive profiles of a surface undergoing sputter erosion

Abstract

The steadily eroding profile of an ion-bombarded solid surface has been extensively studied using the method of characteristics in a kinetic-wave formulation. An alternative method is presented here, based on a construction analogous to that of Huygens for an optical wave-front. It is shown to be formally equivalent to the earlier method in the limit of vanishingly small dose increment, but to confer some advantages in stability on the resulting computer program. Results are presented for the erosion of some simple two-dimensional profiles of an isotropic material. An outline is also given of the extension to surfaces in three dimensions, and to anisotropic materials.