ION-BEAM SPUTTERING TECHNIQUES FOR HIGH-RESOLUTION CONCENTRATION DEPTH PROFILING WITH GLANCING-INCIDENCE X-RAY-FLUORESCENCE SPECTROMETRY

The application of ion beam sputtering in combination with glancing-in cidence X-ray fluorescence spectrometry for high-resolution concentrat ion depth profiling is presented. Two new techniques are described: fi rst, in the ''bevel-etching technique'', the sample depth profile is u ncovered on the sample surface either by sputter etching with a gradie nt of the ion beam intensity or by varying the sputtering time by movi ng a shutter in front of the sample; second, in the ''deposition techn ique'', samples are etched uniformly and the sputtered material is dep osited on a moving substrate. The bevelled sample and also the materia l deposited on the substrate are characterized (laterally resolved) by glancing incidence X-ray fluorescence spectrometry. The apparatus and techniques are described in detail. Typical experiments showing the a dvantages of and problems with the two techniques are discussed. The a chievable depth resolutions, 1.5 nm with the bevel-etching technique a nd 1.4 nm with the deposition technique, are comparable with the best results from other depth profiling methods. (C) 1997 Elsevier Science B.V.