SIMULATIONS OF SUBMICROMETER-SCALE ROUGHENING ON ION-BOMBARDED SOLID-SURFACES

Roughening of amorphous carbon surfaces bombarded by 5-keV Ar ions is studied by using Monte Carlo simulations. Sputtering-induced erosion i s treated in detail by simulating the entire collision cascades origin ated by the bombarding Ar ions. Surface relaxation due to diffusion is described by a Wolf-Villain-type discrete model. The simulations show that bombarded surfaces have self-affine topography on the submicrome ter-scale. For normal incidence the roughness exponent is alpha approx imate to 0.37-0.45, diminishing to alpha approximate to 0.25 when the angle of incidence is increased to 60 degrees. In the studied cases th e roughness exponent alpha is nearly independent of the relaxation of the surface. The dynamic exponent z and growth exponent beta show a cl ear dependence on the relaxation. Without relaxation we found values b eta approximate to 0.3 and z approximate to 1, and with relaxation bet a approximate to 0.14-0.20 and z approximate to 1.6-2.6.