EFFECTS OF LATTICE STEPS IN SURFACE-DIFFUSION AND EPITAXIAL-GROWTH

The lattice step is an integral part of a surface. We report a study o f the behavior of atoms al and near lattice steps since this behavior plays an important role in epilaxial growth and in affecting the struc ture of the thin films, particularly grown from the vapor phase, and a lso the dynamic behavior of the surface at elevated temperature. We us e Ir surfaces as our model system, and study self-diffusion on the ter race as well as along the step edges of the (001) and (111) surfaces u sing the field ion microscope. We also study the descending and ascend ing motion of diffusion atoms at lattice steps and the upward movement of in-layer atoms to the upper terrace.