Dresden 2011 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
DS: Fachverband Dünne Schichten
DS 48: Ion Interactions with Nano Scale Materials III (Focused Session -- Organisers: Diesing, Facsko)
DS 48.3: Vortrag
Donnerstag, 17. März 2011, 16:45–17:00, GER 37
Evolution of surface topography of Si(001) during ion beam erosion — •Martin Engler1, Sven Macko1, Frank Frost2, and Thomas Michely1 — 1II. Physikalisches Institut, Universität zu Köln, Germany — 2Leibniz-Institut für Oberflächenmodifizierung e. V., Leipzig, Germany
We investigated the evolution of surface topography of Si(001) during 2 keV Kr+ ion beam erosion with in-situ STM under UHV conditions for fluences up to 1 × 1022 ions m−2. At room temperature and for an ion incidence angle of ϑ = 75∘ with respect to the surface normal the flat surface rapidly destabilizes. The observed topography changes qualitatively with ion fluence. We have identified a sequence of distinct phases in the surface evolution: a stochastically roughened surface transforms into a ripple pattern and finally into a faceted surface. These phases are governed by different processes. At low fluences the stochastic nature of ion bombardment dominates. With increasing fluence ripples with constant wavelength are selected by an interplay of roughening and smoothening. At high fluences non-linear effects like the gradient dependence of sputtering yield and reflection of ions lead to a faceted topography which coarsens and looses homogeneity in structure size. A similar sequence was observed for impurity induced pattern formation at ϑ = 30∘ although the mechanisms of pattern formation are different.