Dresden 2009 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 10: Surface Modification

DS 10.6: Vortrag

Dienstag, 24. März 2009, 12:15–12:30, GER 37

Mechanisms in low-energy ion beam erosion of fused silica surfaces — •Jens Völlner, Bashkim Ziberi, Frank Frost, and Bernd Rauschenbach — Leibniz-Institut ür Oberflächenmodifizierung (IOM), Permoserstrasse 15, D-04318 Leipzig, Germany

In a recent study the topography evolution of fused silica surfaces under low-energy Ar⁺ ion beam erosion was studied. It was shown that, for ion incidence angles between 50^∘ and 70^∘ the surface topography of fused silica is dominated by regular ripple structures with an orientation perpendicular to the ion beam direction. In contrast, at incidence angles < 50^∘ stable and very smooth surfaces were observed.

Based on this study two special cases have been examined, where rippled surfaces are used as initial surfaces. First a ripple pre-pattern was formed with a characteristic ripple wave vector parallel to ion beam projection. Afterwards the sample was rotated azimuthal by 90^∘ and irradiated again at an (polar) ion incidence angle of 50^∘. Consequential, the original ripple structures disappear slowly and, simultaneously, a new superimposed ripple pattern emerges. In a second set of experiments rippled surfaces are irradiated at incidences angles < 50^∘ and at azimuth angles parallel and perpendicular to the original ripple orientation, where in both cases surface smoothing should be dominating. Based on a detailed analysis of the temporal and the angle dependent evolution of the surface topography gradient dependent sputtering has been identified as the dominating mechanisms responsible for surface topography evolution in this system.