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DS: Fachverband Dünne Schichten

DS 11: Poster Session I: Application of thin films; Ion beam induced surface patterns; Ion and electron beam induced processes; Micro- and nanopatterning (jointly with O)

DS 11.10: Poster

Montag, 11. März 2013, 17:00–20:00, Poster B1

On the origin of surface ripple propagation — •Hans Hofsäss, Kun Zhang, Omar Bobes, and Hans-Gregor Gehrke — II. Physikalisches Institut, U(niversität Göttingen, Germany

The Bradley-Harper theory predicts a lateral propagation of ripples in direction opposite to the incident ion beam dirdction [1]. However, a small or negligible ripple velocity was predicted [2,3]. Aat large incidence angles the propagation velocity should become large and positive, i.e. propagation along the beam direction. Several studies with Ga focused ion beams revealed ripple propagation at high velocities ( +0.4 - +0.8 nm per 1015 ions/cm2) also for small incidence angles <65^∘, and a model able to explain the correct direction and magnitude of ripple propagation was proposed [4]. Wei et al. explained the positive propagation velocity by angle dependent sputtering of asymmetric ripple profiles [5]. We propose an additional mechanism for positive ripple propagation velocities based on ion-induced mass transport. We have measured the ripple propagation velocity for 10 keV Xe on Si and find a velocity of +3 nm per 1015 ions/cm2 at 70^∘ incidence angle.
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