SIMULATIONS OF RIPPLE FORMATION ON ION-BOMBARDED SOLID-SURFACES

Ripple formation on amorphous carbon surfaces bombarded by 5 keV Ar io ns is studied by atomistic simulations. Sputtering is treated in detai l by simulating the entire collision cascades originated by the bombar ding Ar ions. Surface relaxation is described by a Wolf-Villain-type d iscrete model. Ripples and wavelike patterns are observed to emerge on the surface. The ripples have a well-defined wavelength and the orien tation of the wave crests changes from normal to parallel to the beam, when the angle of incidence is increased from 30 degrees to 60 degree s, respectively. The wavelength is found to depend on the magnitude of the diffusion and orientation of the beam as predicted by the continu um theories.