The application of ITTFA and ARXPS to study the ion beam mixing of metal/Si bilayers

Abstract

AbstractMetal/silicon interfaces produced by metal thin film deposition on Si substrates have been ion beam mixed using either Ar+ or reactive N2+ low‐energy ion beams. The ion beam mixing (IBM) has been studied by means of ultraviolet photoelectron spectroscopy (UPS), X‐ray photoelectron spectroscopy (XPS), angle resolved XPS (ARXPS) and iterative target testing transformation factor analysis (ITTFA). The IBM using Ar+ is characterized by the formation of metal silicide. For the IBM interfaces using N2+, a fast nitrogen incorporation in the near surface region, followed by a steady state, is observed. Once the saturation is reached, the Me/Si ratio can be varied in a broad range with a nearly constant nitrogen concentration, as a consequence of sputtering, nitruration and mixing effects taking place simultaneously. The comparison of the experimental results with those obtained from TRIDYN simulations that uses pure ballistic mechanisms, suggests that additional rate‐controlling mechanisms, as radiation‐enhanced diffusion processes or the chemical reaction with nitrogen, have to be considered to explain the IBM of Me/Si interfaces by low‐energy Ar+ and N2+ bombardment. Copyright © 2008 John Wiley & Sons, Ltd.