The mobility of atoms at and near lattice step edges plays an importan
t role in epitaxial growth and surface morphology of thin films, and t
he dynamic behavior of surfaces at elevated temperature. We summarize
our recent FIM studies on how atoms move and bind at step edges, how a
toms can descend and ascend lattice steps, how in-layer atoms can move
up to the upper terrace, and how these atomic processes are related t
o various growth structures in thin film epitaxy.