Berlin 2012 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 38: Poster III: Resistive switching (jointly with DF, KR, HL); Thermoelectric materials (Focused session); Micro- and nanopatterning (jointly with O); Ion irradiation effects

DS 38.24: Poster

Donnerstag, 29. März 2012, 17:30–19:00, Poster E

Evolution of Si surface topography during ion beam erosion at high incidence angles — •Marc Teichmann, Jan Lorbeer, Frank Frost und Bernd Rauschenbach — Leibniz-Institut für Oberflächenmodifizierung e. V., Permoserstr. 15, D-04318 Leipzig

The self-organized pattern formation on Si(001) by low-energy ion beam sputtering at high incidence angels (α ≥ 65 deg) with and without sample rotation is studied.

At ion incidence angles between 65 deg and 85 deg, ripple patterns oriented perpendicular to ion beam direction evolve at low fluences. However, after a certain erosion time, isolated protuberances oriented parallel to the beam direction and with higher amplitude were formed. At a certain fluence the ripple structures vanish with increasing angle of incidence. The amplitude of these protuberances, or columnar structures increases continuously in the fluence range analyzed, i. e. up to 1.3×10¹⁹ cm². These facets are suppressed if the samples are rotated where dot-like structures evolve. The height and size of the dots decreases with increasing rotational speed.

These observations suggest that the angle-dependent sputter yield Y is responsible for the formation of these columnar structures, that is also supported by TRIM.SP [1] calculations. At high angles the slope of the sputter yield curve is much larger than for small angles, i. e. small variations in the surface gradient produce large changes of Y and hence in the local erosion rate.

Support by DFG through FOR 845 is gratefully acknowledged.

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