ATOMIC DETAILS OF STEP FLOW GROWTH ON SI(001)

Growth al step edges by the addition of single adatoms has been studie d using scanning tunneling microscopy (STM). It is shown that the use of empty-state instead of filled-state STM images enables the assessme nt of the binding sites of single adatoms at step edges. We describe a ll different step edge configurations obtained by subsequently stickin g adatoms to these step edges. Adatom diffusion along step edges as we ll as the dimerization of adatoms at a step edge are also demonstrated . Finally, the creation of single dimer vacancies at step edges is dis cussed.