Current-induced non-linear dynamics of voids in metallic thin films: morphological transition and surface wave propagation

Abstract

A theoretical non-linear analysis based on self-consistent numerical simulations is presented of current-induced morphological evolution of void surfaces in metallic thin films. The analysis focuses on cases of low symmetry of surface diffusional anisotropy. Our simulations predict a surface morphological transition and the onset of oscillatory dynamics at a critical strength of the applied electric field. Voids migrate along the film at constant speed with surface morphologies that are either steady or time-periodic, characterized by wave propagation along the surface in the direction of the electric field, for electric fields weaker or stronger than critical, respectively. Both of these types of void surface morphology are stable and do not lead to failure of the metallic thin film.