A method was developed to calculate and use a surface chemical potential which was valid in the large curvature regime for any surface energy function. It was applied to the solid-phase de-wetting of a finite film with an initial rectangular profile and considers the surface diffusion mechanism. For an isotropic surface energy, the film aspect ratio and the adhesion energy between the film and the substrate were shown to be the main parameters that quantify the retraction, the breaking time, and the number of agglomerates. Moreover, it was found that mild surface energy anisotropy with an energy minimum in the horizontal plane postpones the mass detachment. Simple models of the γ-plots for the surface energy illustrate the influence of cusp points on the retraction profiles. Finally, the smooth and facetted experimental surfaces, that were observed in the Si/SiO2 system after 900C annealing under H2, were explained by a quite small anisotropy of the γ-plot.

Surface Diffusion De-Wetting of Thin Solid Films - Numerical Method and Application to Si/SiO2. E.Dornel, J.C.Barbé, F.de Crécy, G.Lacolle, J.Eymery: Physical Review B, 2006, 73[11], 115427 (10pp)