Flux heterogeneity through incidence angle and particle energy in steering-enhanced growth

During growth Van der Waals forces between the incident atoms and the substrate lead to steering with sometimes important implications for the morphology of the molecular-beam-epitaxyor sputter grown films. Deterministic classical trajectory calculations, modelling the atom-substrate interaction with a Lennard Jones potential, have been run to provide insight in the influence of the polar angle of incidence and the energy of the atoms on steering for 1 and 3 monolayer high islands. For low energies ~10–100 meV! substantial flux redistribution has been found. A major part of the flux directed to the ascending steps is transferred on top of the protrusion, while even reversal of the lateral velocity at the descending steps occurs. At grazing incidence strong deviations from geometric shadowing behavior is observed even for energies as high as 1 to 10 eV.