Nanoscale self-affine surface smoothing by ion bombardment

TL;DR

This study investigates how ion bombardment at the nanoscale smooths silicon surfaces, revealing self-affine topography with specific scaling properties at small length scales.

Contribution

It provides experimental evidence of nanoscale surface smoothing and characterizes the self-affine nature of the resulting surface topography.

Findings

Surface smoothing occurs below ~50 nm scale.

The smoothed surface exhibits self-affine scaling with exponent 0.53.

Smoothing is more prominent at smaller length scales.

Abstract

Topography of silicon surfaces irradiated by a 2 MeV Si$^+$ ion beam at normal incidence and ion fluences in the range $10^{15}-10^{16}$ ions/cm$^{2}$ has been investigated using scanning tunneling microscopy. At length scales below $\sim$~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 $\alpha=0.53\pm0.02$.