Auger electron spectroscopy studies of silicon nitride, oxide, and oxynitride thin films: Minimization of surface damage by argon and electron beams

Abstract

The surfaces of silicon oxide, nitride, and oxynitride thin films are susceptible to damage by energetic ion and electron beams so that caution must be exercised in studies of the chemical bonding via Auger electron spectroscopy (AES), x-ray photoelectron spectroscopy, and electron energy-loss spectroscopy; in this paper we focus on the AES spectra. Induced damage is readily evident in the generation of a satellite structure in the AES Si LVV spectrum that results from the creation of Si–Si bonds within the surface region of the dielectric film. We have empirically determined the conditions for minimizing, in some cases effectively eliminating any detectable beam induced damage using Ar ions for sputter cleaning, and electrons for AES excitation. The threshold for electron beam damage is similar in all of the Si dielectrics, whereas the conditions for Ar ion beam are different in the oxides and nitrides.