Regensburg 2010 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 19: Synthesis of Nanostructured Films by Self-organization I (Focused Session)

DS 19.5: Vortrag

Mittwoch, 24. März 2010, 11:45–12:00, H2

Factors influencing metal impurity induced ion beam patterning of Si(001) — •Sven Macko¹, Frank Frost², Bashkim Ziberi², Daniel Förster¹, and Thomas Michely¹ — ¹II. Physikalisches Institut, Universität zu Köln, Germany — ²Leibniz-Institut für Oberflächenmodifizierung e. V., Leipzig, Germany

On Si(001) ion beam pattern formation at angles ϑ < 45^∘ with respect to the surface normal takes only place in the presence of metal impurities. Here we report experiments addressing the factors influencing impurity induced pattern formation using well controlled UHV experiments. Ion erosion is performed through fluences > 5 × 10²¹ ions/m² of 2 keV Kr⁺ with a differentially pumped fine focus ion source. Co-deposition of metal impurities is performed through co-sputtering and co-evaporation of Fe. With increasing Fe concentration under otherwise identical conditions a smooth unpatterned surface, a dot pattern and finally for the highest Fe concentrations a ripple pattern is observed. Co-sputtering measurements at temperatures below and above room temperature lead to identical pattern sequences. Thus thermal diffusion is irrelevant for ion beam pattern formation on Si(001) at room temperature. Finally, the orientation of ripple patterns appears to be associated with the direction of impinging Fe atoms.