Morphological stability of a heterophase interface under electromigration conditions

The evolution of the interface between two mutually insoluble metallic phases, under the influence of a strong electric field is examined. A slight perturbation of the interface away from a plane y5h(x) leads to a component of the electric field along the interface. This creates a diffusion flux of the individual atoms along the interface which, in turn, leads to an increase in the amplitude of the initial perturbation and thus to an interfacial profile instability. The processes is expected to be controlled by interface diffusion in response to three distinct driving forces: the electric field, internal stresses ~which arise due to the accumulation or depletion of matter at the interface!, and the interfacial curvature. The stress distribution along the interface was found from a self-consistent solution of the elastic problem. For the instability to occur, differences in effective atomic charges, elastic moduli and/or atomic mobilities of the two constituent metals are required. Small sinusoidal corrugations are shown to grow with time for a range of wavelengths. The corrugations can grow monotonically or vary in oscillatory manner, depending on their wavelength. © 1996 American Institute of Physics. @S0021-8979~96!06608-3#