NONLINEAR-ANALYSIS OF THE MORPHOLOGICAL EVOLUTION OF VOID SURFACES INMETALLIC THIN-FILMS UNDER SURFACE ELECTROMIGRATION CONDITIONS

A theoretical analysis is presented of the non-linear dynamics of void surface morphology in metallic thin films under the action of an elec tric field that induces surface electromigration. Self-consistent dyna mical simulations aided by the conclusions of linear stability theory reveal the important role of the anisotropy of void surface diffusivit y, the strength of the applied electric field, and the void size in th e dynamics. Special emphasis is placed on void dynamics in cases of lo w symmetry of surface diffusion anisotropy. Our simulations predict vo id faceting and wedge-shaped void formation, failure of the metallic f ilms due to propagation of slit-like features from the void surface, a s well as propagation of soliton-like features on void surfaces prior to failure. The simulation predictions are in excellent agreement with recent experimental observations. (C) 1998 Elsevier Science B.V. All rights reserved.