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Simultane Bestimmung von Schichtdicke und Zusammensetzung bei dünnen Filmen und Mehrschichtsystemen mit Hilfe der Elektronenstrahl-Mikrosonde

: Schiffmann, K.I.

Univ. Kiel, Mineralogisches Institut:
COMETT-Bericht. Seminar im Rahmen des EG-Projekts COMETT. Elektronenstrahl-Röntgenmikroanalyse -ERMA- zur Qualitätssicherung fester Stoffe in der Medizintechnik
Kiel, 1992
Elektronenstrahl-Röntgenmikroanalyse -ERMA- zur Qualitätssicherung fester Stoffe in der Medizintechnik <1992, Kiel>
Conference Paper
Fraunhofer IST ()
chemical composition; electron probe microanalysis; EPMA; film thickness determination; thin films

Electron probe microanalysis (EPMA) offers the possibility to investigate very thin films having a typical thickness of 10 to 1000 nm. Based on the PAP-model of Pouchou and Pichoir a analysis method is presented which enables determination of composition and film thickness of single films or multilayer system on a substrate. The results agree within 3-5% with those obtained by reference methods. THIN FILM ANALYSIS is characterized by the situation that the energy of the exciting electrons is chosen in a way that the ionization depth is high in comparision with the film thickness. In this case the X-ray intensities of the elements in the film do not only depend on the composition of the film but also of the film thickness and the atomic number of the substrate. Therefore, it is possible to determine not only the concentration of the elements in the film but also the film thickness down to the range of nanometers. The range of application should typically be restricted to films having a thickness of less then 0.5-1.0 microns. Application to multilayers requires the following conditions: 1. The substrate must be defined in respect of its mean atomic number. 2. The sequence of a multilayer configuration must be known. 3. Each element is only allowed to be a component of one layer or the substrate. 4. Each layer has to be homogeneous in respect of its composition (no concentration gradients.) Under these conditions only one measurement at one energy Eo is sufficient for the determination of composition and thickness of all layers.