Surface diffusion dewetting of thin solid films: Numerical method and application toSi∕SiO2

A method has been developed to calculate and use a surface chemical potential which is valid in the large curvature regime for any surface energy function. It is applied to the solid-phase dewetting 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 are shown to be the main parameters that quantify the retraction, the breaking time, and the number of agglomerates. Moreover, it is found that mild surface energy anisotropy with an energy minimum in the horizontal plane postpones the mass detachment. Simple models of the $\ensuremath{\gamma}$-plots for the surface energy illustrate the influence of cusp points on the retraction profiles. Finally, the smooth and facetted experimental surfaces, that are observed in the $\mathrm{Si}∕{\mathrm{SiO}}_{2}$ system after $900\phantom{\rule{0.2em}{0ex}}\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}$ annealing under ${\mathrm{H}}_{2}$, are explained by a quite small anisotropy of the $\ensuremath{\gamma}$-plot.