MODELING ION-BOMBARDMENT INDUCED SUBMICRON-SCALE SURFACE ROUGHENING

Ion bombardment induced surface roughening in submicron-scale is model led. The effect of ion beam on the evolution of the surface is describ ed as a Levy stable shot noise. Height fluctuations are assumed to be smoothed out only by surface tension or diffusion, which is driven by height gradient. The resulting noise driven diffusion equation leads t o the development of self-affine surfaces, where the roughness exponen t ct depends on the distribution of noise amplitude. High values of al pha approximate to 0.5 recently observed in experiments are shown to r esult from a shot noise proportional to the typical recoil displacemen ts in cascades created by low energy, heavy ion bombardment.