DETERMINATION OF THE COMPOSITION OF SPUTTERED SILICON OXYNITRIDE FILMS BY AUGER-ELECTRON SPECTROSCOPY AND RUTHERFORD BACKSCATTERING SPECTROMETRY

In recent years silicon oxynitride films have received growing interest for microelectronics-related applications, e.g. as oxidation and diffusion barriers in field effect devices. It is well-knwon from various reports that the O:N ratio in the deposited films varies rapidly with the O2:N2 ratio in the sputter ambient within a rather narrow partial pressure regime. There is evidence for appreciable differences between the atomic O:N ratios when different deposition techniques are used. In order to have sufficient correlation between the film stoichiometry and other film properties and also to have a basis for comparison between characteristics of films deposited by different techniques, it is necessary to know the true O:N atomic ratios in the films or at least the functional dependence of O:N (film) on O2:N2 (sputter ambient). The aim of this work was to compare AES and Rutherford backscattering spectrometry (RBS) experimental results from silicon oxynitride films of various composition, since RBS gives information about the film bulk stoichiometry independently.