Off-normal ion erosion of silicon – simultaneous observation of two ripple modes


Off-normal ion erosion of silicon – simultaneous observation of two ripple modes

Keller, A.; Roßbach, S.; Facsko, S.; Möller, W.

It is well known that oblique low and mediate energy (typically 0.1 – 100 keV) ion erosion of solid surfaces can lead to the formation of periodic ripple patterns with wavelength ranging from 10 to 1000 nm. These structures were found on a large variety of materials, such as semiconductors, metals, and insulating surfaces [1]. The first attempt to describe the formation of surface ripples was made by Bradley and Harper [2]. In their framework the ripples are either parallel or perpendicular to the direction of the ion beam, depending on the angle of incidence. This was also shown experimentally on HOPG [3].
In the presented work we studied the formation of ripples on Si(100) surface under sub-keV Ar+ bombardment using ex-situ AFM. In addition to previous experimental observations two simultaneous ripple modes are found with direction perpendicular and parallel to the ion beam, respectively. The dependence of each mode on ion energy, fluence, flux, and incidence angle is investigated. The two modes have wavelengths of some ten and a few hundred nanometres and show different temporal behaviour. Finally, our observations are compared to simulations based on the damped Kuramoto-Sivashinsky equation [4].

[1] M. A. Makeev et al., Nucl. Inst. Meth. Phys. Res. B 197 (2002), 185
[2] R. Bradley and J. Harper, J. Vac. Sci. Technol. A 6 (1988), 2390
[3] S. Habenicht et al., Phys. Rev. B 60 (1999), R2200
[4] S. Facsko et al., Phys. Rev. B 69 (2004), 153412

  • Lecture (Conference)
    22nd International Conference on Atomic Collisions in Solids, 21.-26.07.2006, Berlin, Deutschland

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