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Morphological stability of electromigration-driven vacancy islands

Frank Hausser·Philipp Kuhn·Joachim Krug·Axel Voigt
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Abstract

The electromigration-induced shape evolution of two-dimensional vacancy islands on a crystal surface is studied using a continuum approach. We consider the regime where mass transport is restricted to terrace diffusion in the interior of the island. In the limit of fast attachment/detachment kinetics a circle translating at constant velocity is a stationary solution of the problem. In contrast to earlier work [O. Pierre-Louis and T.L. Einstein, Phys. Rev. B 62, 13697 (2000)] we show that the circular solution remains linearly stable for arbitrarily large driving forces. The numerical solution of the full nonlinear problem nevertheless reveals a fingering instability at the trailing end of the island, which develops from finite amplitude perturbations and eventually leads to pinch-off. Relaxing the condition of instantaneous attachment/detachment kinetics, we obtain non-circular elongated stationary shapes in an analytic approximation which compares favorably to the full numerical solution.

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Frank Hausser, Philipp Kuhn, Joachim Krug, Axel Voigt. 2007-02-20. Morphological stability of electromigration-driven vacancy islands. https://doi.org/10.1103/physreve.75.046210

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