Regensburg 2013 – scientific programme

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DS: Fachverband Dünne Schichten

DS 18: Micro- and Nanopatterning (jointly with O)

DS 18.1: Talk

Wednesday, March 13, 2013, 09:30–09:45, H8

Evolution of Ge surface topography during low energy ion beam erosion — •Marc Teichmann, Jan Lorbeer, Frank Frost, and Bernd Rauschenbach — Leibniz-Institut für Oberflächenmodifizierung e.V., Permoserstraße 15, 04318 Leipzig, Germany

The self-organized pattern formation on Ge(100) by low-energy ion beam sputtering with noble gases is studied. We investigated the surface topography in dependency on the angle of incidence. Furthermore the evolving structures are investigated as a function of ion beam energy in the range from 400 eV up to 2000 eV and in a fluence range form 1.1×10¹⁸ cm² until 1.3×10¹⁹ cm².

The surface remains flat up to an angle of incidence of about 60 deg before a ripple pattern evolves at higher angles with wave vector parallel to the projection of the ion beam. This pattern also vanishes at 75 deg when a saw tooth profile evolves on the surface. At grazing incidence a pattern emerges with wave vector perpendicular to the ion beam. Furthermore we observe an energy dependency on the transition between smoothening and patterning and a temporal coarsening of the structures. The observations suggest that the projectile mass is an important parameter for pattern formation and gradient dependent sputtering is a main mechanism of surface destabilization which is also supported by TRIM.SP [1] calculations that also reveal that reflected ions can contribute to surface stabilization and surface smoothing.

Support by Deutsche Forschungsgemeinschaft through FOR 845 is gratefully achknowledged.

[1] J. P. Biersack, W. Eckstein, Appl. Phys. A, 34, 73-94 (1984).