Microsc. Microanal. Microstruct. 6, 421-432 (1995)
DOI: 10.1051/mmm:1995132

EPMA Sputter Depth Profiling: A New Technique for Quantitative in-Depth Analysis of Layered Structures

Peter Karduck¹ et Alexander von Richthofen<sup>2

1</sup>  Gemeinschaftslabor für Electronenmikroskopie, GFE, Rheinisch-Westfälische Technische Hochschule Aachen, 52056 Aachen, Germany
²  Lehrstuhl für Theoretische Hüttenkunde, Rheinisch-Westfälische Technische Hochschule Aachen, 52056 Aachen, Germany

Abstract
The remarkable features of modern EPMA techniques are high sensitivity for very small coverages of thin films on substrates ( ) and a reliable quantitative determination of elemental compositions. The present work makes use of these features and combines them with ion sputtering of the sample surface surface to extend the capability of EPMA to real in-depth analysis in the submicron range. The general theoretical background of this EPMA-sputter-depth profiling is worked out and on the 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 quantitatively with regard to both composition and the real depth coordinate in terms of mass coverage. After having been verified at an artificial layer system of different Ti-Al-N-O-compounds, the new technique was used to study oxide scales which were grown on technical hardcoatings of the type with different fractions 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 e relative accuracy of 10%. Additionally reasonable evaluation of the depth coordinate in mass coverage could be attained, the results of which could be assessed by SEM imaging of the scales in fractured samples.

PACS
8280P - Electron spectroscopy for chemical analysis photoelectron, Auger spectroscopy, etc..
6855 - Thin film growth, structure, and epitaxy.
6820 - Solid surface structure.

Key words
aluminium compounds -- electron probe analysis -- surface structure -- surface topography -- thin films -- titanium compounds -- EPMA sputter depth profiling -- quantitative in depth analysis -- layered structures -- thin films on substrates -- very small coverages -- Monte Carlo simulation model -- reconstruct surface near depth profiles -- multiple thin film model -- Ti Al N O compounds -- oxide scales -- roughness -- fractured samples -- Ti Al N O


© EDP Sciences 1995