Berlin 2008 – scientific programme
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O: Fachverband Oberflächenphysik
O 53: Surface Nanopatterns
O 53.3: Talk
Wednesday, February 27, 2008, 15:45–16:00, MA 043
X-ray scattering and diffraction from Xe-induced ripples in crystalline silicon — •Andreas Biermanns1, Ullrich Pietsch1, Souren Grigorian1, Jörg Grenzer2, Stefan Facsko2, Antje Hanisch2, Dina Carbone3, and Hartmut Metzger3 — 1Universität Siegen, Germany — 2Foschungszentrum Dresden-Rossendorf, Germany — 3ID01 beamline, ESRF, France
The formation of surface-nanostructures with a characteristic size ranging from several nanometer up to microns has attracted significant interest in the last decades in the context of fabrication of novel opto-electronic and storage devices. One kind of those nanostructures are wave-like patterns (ripples) produced by an interplay between a roughening process caused by ion beam erosion (sputtering) of the surface and smoothening processes caused by surface diffusion. In this contribution we report on investigations of patterned Si (001) surfaces after irradiation with Xe+-ions using ion-energies up to 40keV. During the sputtering, an amorphous surface-layer is formed followed by a rather sharp interface towards crystalline material, showing the same morphology as the surface. The structures of the amorphous layer and the amorphous-crystalline interface were studied by means of grazing-incidence - small angle scattering (GISAXS) and diffraction (GID) using synchrotron-radiation. We found that the crystal structure at the interface is expanded along the ripples, caused by the creation of defects inside the surface region, whereas this expansion is strongly reduced across the ripples. This different relaxation may play a driving role in pattern formation at the interface.