Argon-ion assisted etching of silicon by molecular chlorine

Abstract

Argon-ion assisted etching of silicon by molecular chlorine has been investigated. The masses and some kinetic energy distributions of the neutral particles emitted from the surface have been determined by mass spectrometry and time-of-flight spectra. It is found that an important part of the silicon-containing particles consists of SiCl and SiCl2 molecules which have kinetic energies in the eV region. The observations exclude a simple evaporation of SiCl4 at the target temperature. A tentative model—consisting of a collision cascade like process parallel to thermal evaporation at the substrate temperature induced by a reduction of the effective surface binding energy during a sputtering event—is given to explain the observed kinetic energy distributions qualitatively.