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DS: Dünne Schichten

DS 17: Ion beam solid interaction II

DS 17.5: Vortrag

Donnerstag, 30. März 2006, 12:15–12:30, GER 37

Dewetting of thin metal-oxide films on silicon under swift heavy ion bombardment — •Thunu Bolse¹, Klara Lyutovich², Hartmut Paulus¹, Bouchaib Bouhachi¹, Siegfried Klaumünzer³, and Wolfgang Bolse¹ — ¹Institut für Strahlenphysik, Universität Stuttgart — ²Institut für Halbleitertechnik, Universität Stuttgart — ³Hahn-Meitner Institut Berlin

Dewetting, occuring when a thin film on a non-wettable substrate is transferred to its molten state, has gained strong interest during the last decade, since it results in nano-scale, large-area-covering patterns. Recently we found that swift heavy ion irradiation of thin NiO-, Fe₂O₃- and TiO₂-films on Si at 80 K results in amazingly similar dewetting pattern, although in this case the coating has never reached its melting point. SEM analysis clearly reveals that similar dewetting mechanisms as for liquid films were active. AFM shows that the circular holes formed in the early stages of the dewetting process exhibit the same rim-structure as in the case of thermally driven dewetting. RBS was used to measure the open surface of the film as a function of the fluence. The substrate coverage decreases with increasing fluence and reaches a saturation value after the holes coalesce. The different dewetting stages exhibit different kinetics, from which conclusions concerning the involved processes can be drawn. The observed dewetting pattern and kinetics will be discussed in close comparison with the models developed for dewetting of liquid films with special attention to the fact, that here mass transport can occur only step-by-step in a highly localised nano-scale region during the excited stage of the ion track.