Numerical Investigation on Origin of Microscopic Surface Roughness during Si Etching by Chemically Reactive Plasmas

Abstract

A key factor for the formation of nanoscale surface roughness during chemically reactive plasma and beam etchings has been distinguished by classical molecular dynamics (MD) simulations using well-known Stillinger–Weber potential models. In this study, MD simulations of Si(100) etching using monoenergetic (=100 eV) Cl+ and Br+ beams were performed. On the basis of analyses of surface structures and ion trajectories, it was concluded that the penetration of impinging species into the Si surface and residual halogens inside the Si lattice is a crucial factor for enhancing the surface roughness. The accurate estimation of potential energies for the penetration into interstitial sites is essential for further qualitative improvement of etching simulations.