Evolution of surface topography of fused silica by ion beam sputtering

The evolution of the surface topography of fused silica during low-energy A r ion beam sputtering was studied by atomic force microscopy. Depending on the incidence angle of the ion beam and the ion energy the topography was d ominated by regular ripple structures with an orientation perpendicular or parallel to the ion beam direction and a characteristic wavelength), betwee n 30 and 300 nm. The time evolution of the ripple wavelength follows the po wer law lambda similar to t while gamma depends on the ion beam parameters. In addition, we found a distinct energy dependence of the ripple wavelength as well as the resulting scaling behaviour of the surface roughness. These results will be discussed within the limits of existing continuum models f or surface erosion by ion sputtering. (C) 2001 Elsevier Science B.V. All ri ghts reserved.