SIMULATIONS OF SELF-AFFINE ROUGHENING AND RIPPLE FORMATION ON ION-BOMBARDED AMORPHOUS-CARBON SURFACES

Sputtering roughening and ripple formation on amorphous carbon surface s bombarded by 2, 5 and 10 keV Ar- and Xe-ions are studied by using Mo nte Carlo simulations, where sputtering is treated in detail by simula ting the entire collision cascades and the surface relaxation is descr ibed by a Wolf-Villain-type model. The simulations show that bombarded surfaces have self-affine topography on a scale comparable to the cas cade dimension, and on larger scales ripples are formed on the surface . In case of the Ar-ion bombardment the wavelength of the ripples depe nd on the magnitude of the diffusion and on the orientation of the bea m as predicted by the continuum theories. In case of the Xe-ion bombar dment ripples with well-defined wavelengths were found only at an angl e of incidence 60 degrees. In all cases the ripple wavelength was foun d to increase with the increasing bombarding energy.