EPMA SPUTTER DEPTH PROFILING - A NEW TECHNIQUE FOR QUANTITATIVE IN-DEPTH ANALYSIS OF LAYERED STRUCTURES

The remarkable features of modern EPMA techniques are high sensitivity for very small coverages of thin films on substrates (10(14) Cm-2) an d a reliable quantitative determination of elemental compositions. The present work makes use of these features and combines them with ion s puttering of the sample surface to extend the capability of EPMA to re al in-depth analysis in the submicron range. The general theoretical b ackground of this EPMA-sputter-depth profiling is worked out and on th e basis of a Monte-Carlo simulation model a technique was developed to reconstruct surface near depth profiles by a multiple thin film model . As a result, this new approach is able to determine depth profiles q uantitatively with regard to both composition and the real depth coord inate in terms of mass coverage. After having been verified at an arti ficial layer system of different Ti-Al-N-O-compounds the new technique was used to study oxide scales which were grown on technical hardcoat ings of the type Ti1-xAlxN with different fractions a(x). Despite the roughness of the oxide scales and although the structure of different oxide types was interlocked the variation of the elemental composition with depth could be worked out quantitatively with a relative accurac y of 10%. Additionally a reasonable evaluation of the depth coordinate in mass coverage could be attained, the results of which could be ass essed by SEM imaging of the scales in fractured samples.