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DS: Fachverband Dünne Schichten

DS 24: Ion Beam Techniques

DS 24.2: Vortrag

Donnerstag, 29. März 2007, 11:30–11:45, H34

Energy dependence of the surface topography on Si and Ge during ion beam erosion: Change of ripple orientation — •Bashkim Ziberi, Frank Frost, Theresa Lutz, and Bernd Rauschenbach — Leibniz-Institut für Oberflächenmodifizierung e. V., 04318 Leipzig

Under certain conditions, induced by self-organization processes, low-energy ion beam erosion can lead to the formation of well ordered nanostructures on surfaces. The formation, ordering and size of nanostructures depends on different process conditions. The underlying mechanism is an interplay between curvature dependent sputtering that roughness the surface and smoothing by different relaxation processes. In the case of ripple formation current theories predict a ripple orientation perpendicular to the projection of the incoming ion beam for not too oblique angles of ion incidence and an increase of the ripple wavelength with ion energy if the relaxation process is not a thermal activated surface diffusion process. In this contribution the ripple surface topography emerging on Si and Ge surfaces during low energy Xe⁺ ion beam erosion at oblique ion incidence is investigated (ion energy ≤ 2000 eV). The results show that there is a much more complex behavior of the surface topography with ion energy, that contradict the predictions of the theoretical models. For example a change in ripple orientation from perpendicular to parallel with decreasing ion energy was found, and the ripples formed at lower ion energies have a wavelength two times larger than the ripples at higher ion energies.