AVS 49th International Symposium
    Surface Science Monday Sessions
       Session SS2-MoA

Paper SS2-MoA4
The 'Three-Dimensional' Schwoebel-Ehrlich Barrier in Ag Crystallite Growth on Si(111)

Monday, November 4, 2002, 3:00 pm, Room C-110

Session: Nucleation & Growth of Metals on Oxides & Semiconductors
Presenter: M.S. Altman, Hong Kong University of Science and Technology
Authors: W.X. Tang, Hong Kong University of Science and Technology
K.L. Man, Hong Kong University of Science and Technology
H. Huang, Hong Kong Polytechnic University
M.S. Altman, Hong Kong University of Science and Technology
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Growth morphology will be affected, or even dictated, by kinetic limitations that may be present during growth. One such limitation, which has received a great deal of attention, occurs in growth at surfaces when there is a Schwoebel-Ehrlich (SE) diffusion energy barrier to atomic motion descending a monolayer height step. We present evidence of an analogous 'three-dimensional' (3D) SE energy barrier to atomic diffusion across the ridge that separates two facets on a three-dimensional crystal. The 3D SE barrier stems from the reduced coordination at the ridge. Differences of the adatom formation energies on adjacent facets cause the 3D SE barrier to be asymmetric. Kinetically limited growth shapes of Ag crystallites on the Si(111) surface have been studied with low energy electron microscopy (LEEM) and diffraction (LEED). These growth shapes are in agreement with expectations from the asymmetry of the 3D SE barriers. LEEM observations of the modification of growth shapes caused by codeposition of surfactants are also consistent with modification of the 3D SE barrier caused by surface passivation. The 3D SE barrier is expected to be relevant to diffusion in the presence of multilayer height steps on surfaces, and is therefore also important for the development of film texture.