Comparison of shallow depth profiles of cobalt-implanted Si wafers determined by total reflection x-ray fluorescence analysis after repeated stratified etching and by Rutherford backscattering spectrometry

Thin and shallow layers of some 50-150 nm were produced by ion implantation of Co ions in Si wafers and afterwards characterized by concentration-dept h profiling. Two methods were applied for that purpose: a novel method comb ining a stepwise wet-chemical etching of an implanted wafer with total refl ection x-ray fluorescence spectrometry (TXRF) and the well-known method of Rutherford backscattering spectrometry (RBS) of the original non-etched waf er. The corresponding profiles agree quite well for both methods, demonstra ting a high accuracy of both the novel and established method. The characte ristic parameters of the profiles, e.g. concentration and depth at the maxi mum, mean depth, full width at half-maximum and total dose, show relative d eviations of only 4-6% between both methods. Such good agreement was ensure d by results traceable to SI units: mass per mass (g g(-1)) and depth (m), In addition to the accuracy, further figures of merit, such as detection li mit and depth resolution, were discussed in order to demonstrate the high e ffectiveness and analytical potential of the novel method. Copyright (C) 19 99 John Wiley & Sons, Ltd.