Is keV ion induced pattern formation on Si(001) caused by metal impurities?

Abstract

We present ion beam erosion experiments performed in ultra high vacuum using a differentially pumped ion source and taking care that the ion beam hits the Si(001) sample only. Under these conditions no ion beam patterns form on Si for angles below 45 degrees with respect to the global surface normal using 2 keV Kr ions and fluences of 2 x 10^22 ions/m^2. In fact, the ion beam induces a smoothening of preformed patterns. Simultaneous sputter deposition of stainless steel in this angular range creates a variety of patterns, similar to those previously ascribed to clean ion beam induced destabilization of the surface profile. Only for grazing incidence with incident angles between 60 degrees and 83 degrees pronounced ion beam patterns form. It appears that the angular dependent stability of Si(001) against pattern formation under clean ion beam erosion conditions is related to the angular dependence of the sputtering yield, and not primarily to a curvature dependent yield as invoked frequently in continuum theory models.

arXiv comment15 pages, 7 figures. This is an author-created, un-copyedited version of an article published in Nanotechnology. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it

References in corpus (2)

• Self-Organized Ordering of Nanostructures Produced by Ion-Beam Sputtering
• Production of ordered silicon nanocrystals by low-energy ion sputtering

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• Stability analysis of a viscoelastic model for ion-irradiated silicon
• Crater functions for compound materials: a route to parameter estimation in coupled-PDE models of ion bombardment
• Morphological Transitions in Nanoscale Patterns Produced by Concurrent Ion Sputtering and Impurity Co-deposition
• Ion-beam nanopatterning of silicon surfaces under co-deposition of non-silicide-forming impurities
• Producing nanodot arrays with improved hexagonal order by patterning surfaces before ion sputtering