Open Access Nano Express

Transition from ripples to faceted structures under low-energy argon ion bombardment of silicon: understanding the role of shadowing and sputtering

Tanmoy Basu, Debi Prasad Datta and Tapobrata Som*

Author Affiliations

SUNAG Laboratory, Institute of Physics, Sachivalaya Marg, Bhubaneswar 751 005, India

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Nanoscale Research Letters 2013, 8:289  doi:10.1186/1556-276X-8-289

Published: 19 June 2013

Abstract

In this study, we have investigated temporal evolution of silicon surface topography under 500-eV argon ion bombardment for two angles of incidence, namely 70° and 72.5°. For both angles, parallel-mode ripples are observed at low fluences (up to 2 × 1017 ions cm-2) which undergo a transition to faceted structures at a higher fluence of 5 × 1017 ions cm-2. Facet coarsening takes place at further higher fluences. This transition from ripples to faceted structures is attributed to the shadowing effect due to a height difference between peaks and valleys of the ripples. The observed facet coarsening is attributed to a mechanism based on reflection of primary ions from the facets. In addition, the role of sputtering is investigated (for both the angles) by computing the fractional change in sputtering yield and the evolution of surface roughness.

81.05.Cy, 81.16.Rf, 61.80.Jh, 87.64.Dz

Keywords:
Silicon; Ion beam patterning; Atomic force microscopy