Nanoscale self-affine surface smoothing by ion bombardment

Abstract

The topography of silicon surfaces irradiated by a 2-MeV Si⁺ ion beam at normal incidence and ion fluences in the range 10¹⁵-10¹⁶ions/cm² has been investigated using scanning tunneling microscopy. At length scales below ~50 nm, surface smoothing is observed; the smoothing is more prominent at smaller length scales. The smoothed surface is self-affine with a scaling exponent α=0.53± 0.03.