Prakt. Met. Sonderband 38 (2006) 185 
CHARACTERISATION OF THE MATERIALS AND COATINGS 
MICROSTRUCTURE USING FIB AND Ar” - ION ETCHING 
J. Wosik’, R. Sonnleitner’, G.E. Nauer'? 
' ECHEM - Centre of Competence in Applied Electrochemistry, A-2700 Wiener Neustadt, 
Austria 
2 Institute of Physical Chemistry, University Vienna, A-1090 Wien, Austria 
ABSTRACT 
The revealing of the materials microstructure using Ar” - lon Etching by ann Precision 
Etching and Coating System (PECS™) and Focus lon Beam (FIB) techniques is described 
and discussed. The advantages and disadvantages of both methods in respect to 
materials preparation and characterisation are demonstrated on selected samples. 
Different kinds of materials were chosen for investigations to give a better overview on the 
both methods possibilities. FIB technique is very useful for the visualisation of 
crystallographical defects with high disorientation angle like twins, whereas PECS reveals 
even small crystallographical differences (subgrains, dislocation walls) induced through 
plastic deformation. For the optimum performance (etching and visualisation) the 
knowledge of the precise etching and visualisation parameters is necessary. 
1. INTRODUCTION 
For the precise investigation of materials (microstructure, its crystallographical 
components as well as chemical composition) a precise characterisation of the 
microstructural features is necessary. Modern micro- and nanostructured materials (for 
example coatings, multilayers with a thickness resp. layer’s period below 1 um) demand 
special techniques for the visualization of the structure components. The combination of 
Ar*- ion and Focused lon Beam (FIB) etching techniques offers new possibilities for 
materials characterisation. 
The principle of the etching using Ar" ions and FIB are similar in some respects. In both 
cases ions, are accelerated and hit the surface of the specimen removing layers of atoms. 
The rate of the materials removal/etching depends strongly on the process parameters 
(accelerating voltage, ion energy, ion current, the mass of the ions, as well as the kind of 
etched material, crystallographic structure. orientation. etc). The two techniques are 
different in some aspects: 
the ion beam is focused in FIB, whereas spread in PECS, 
PECS uses Ar" ions, whereas FIB Ga" ions, 
FIB allows the direct observation of the etching process (in situ), 
the crystallographical contrast is strongly enhanced by using FIB based on the 
channeling effect.