Evolution of the mound morphology in (111) oriented polycrystalline Pd films and Co Pd multilayered films with Pd underlayers

Pd thin films and Co/Pd multilayered films with progressively thicker Pd underlayers are prepared by physical vapor depositions. Their growth behaviors are investigated using atomic force microscopy and transmission electron microscopy. We observed that a mound occurs on top of each crystallite of (111) oriented polycrystalline Pd films and that the average mound size increases according to the capillary-induced coalescence mechanism. We attribute this observed growth instability to the step barrier which resists step-down diffusion of deposited atoms. We also observed that the mound slopes of Co/Pd multilayers are smaller than those of their Pd underlayers. We suggest that this results from a downhill current driven by the interface energy between the Co and Pd layers. (C) 1999 American Institute of Physics. [S0021-8979(99)04712-X].