One and Two-Dimensional Pattern Formation on Ion Sputtered Silicon

Abstract

The evolution of surface morphology during ion beam erosion of Si(111) at glancing ion incidence (60o from normal, 500 eV Ar+, 0.75 mA/cm2 collimated beam current) was studied over a temperature range of 500-730o Celsius. Keeping ion flux, incident angle, and energy fixed, it was found that one-dimensional sputter ripples with wavevector oriented perpendicular to the projected ion beam direction form during sputtering at the lower end of the temperature range. For temperatures above approximately 690o Celsius, growth modes both parallel and perpendicular to the projected ion beam direction contribute to the surface morphological evolution. This effect leads to the formation of bumps (“dots”) with nearly rectangular symmetry.