Ion-surface interactions in plasma etching

Abstract

The surface chemistry and the etching behavior of silicon and oxidized silicon bombarded with a CF₃⁺ ion beam (50–4000 eV) have been studied using Auger electron spectroscopy, and a quartz‐crystal microbalance. The conclusions of this study are as follows: (a) the etch rate of Si caused by CF₃⁺ ion bombardment can be accounted for by physical sputtering; (b) the deposition and removal of carbon at the etched surface may be one of the most important phenomena affecting the operation of plasma‐etching systems; and (c) there is reason to believe that ion bombardment of the etched surface enhances the reaction rate of the neutral etching species which are most probably fluorine atoms and CF₃ radicals.