Surface modification with ionised cluster beams: Modelling

Impacts of accelerated cluster ions which consist of hundreds of atoms on a solid surface have shown new surface smoothing and roughening effects. Hybrid Molecular Dynamics (MD) and a two-dimensional MD method were used to simulate rapid collision processes at the target impact zone and the subsequent thermalization. Gas clusters impacting on metal and semiconductor target surfaces have been considered to study the ripple formation under irradiation with oblique cluster beams. The dynamics of surface modification is simulated by using a discrete model which contains crater formation and surface relaxation. The continuum description of a surface relaxation is based on a dynamics equation for surface heights containing viscous flow, surface tension, surface diffusion, and crater formation terms. Comparison of the results of the simulation with experimental data shows qualitative agreement.