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ICMCTF 2012! - CD-Lab Application Oriented Coating Development

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Advanced Characterization of <strong>Coating</strong>s and Thin Films<br />

Room: Sunrise - Session TS2-1<br />

Advanced Characterization of <strong>Coating</strong>s and Thin Films<br />

Moderator: P. Schaaf, TU Ilmenau, Germany, F. Giuliani,<br />

Imperial College London - South Kensington Campus, UK,<br />

S. Korte, University of Erlangen-Nürnberg, Germany<br />

10:00am TS2-1-1 3D Microstructure Analysis of Thin Films and<br />

<strong>Coating</strong>s in the Micro, Nano and Atomic Scale, F. Mücklich<br />

(muecke@matsci.uni-sb.de), Saarland University and Materials Engineering<br />

Center, Germany INVITED<br />

The quantitative investigation of the correlation between processing,<br />

(spatial) microstructure and properties of coatings and thin films is one of<br />

the essential goals of their characterization strategies. The traditional 2D<br />

planar section sampling combined with estimations for the spatial situation<br />

is powerful but it supplies insufficient information for essential 3D<br />

characteristics such as particle volume density and arrangement or<br />

connectivity in cases of complex shaped microstructures. Advanced thin<br />

films therefore call for an adequate imaging and quantification of the 3D<br />

microstructure. Electron tomography is well established but may suffer<br />

from a lack of field of view size. Such representative field of view size can<br />

be achieved by the help of microstructure tomography based on FIB serial<br />

sectioning. This method combines the excellent target preparation<br />

possibilities of a focused ion beam (FIB) with all types of SEM contrast<br />

including EDX and EBSD. Therefore it enables the exploration of a<br />

representative sample volume and the imaging of chemical and structural<br />

phenomena with a resolution of a few nanometers. This can be combined<br />

locally with a tomography even at the atomic scale using Atom Probe<br />

Tomography.<br />

Once the 3D data set is available, their exploitation in 3D image analysis<br />

provide detailed quantitative insights into the relation between processing,<br />

structure and properties.<br />

So far, the complex formation of multiphase 3D microstructures, the related<br />

interface as well as seeding phenomena and also local degradation effects<br />

were investigated. The talk will provide an overview of microstructure<br />

tomography supported by examples of some technical relevance of<br />

coatings, thin films, and surface effects.<br />

10:40am TS2-1-3 Atom probe tomography of self-organized<br />

nanostructuring in Zr-Al-N thin films, L. Johnson (larsj@ifm.liu.se), N.<br />

Ghafoor, Linköping University, Sweden, M. Thuvander, K. Stiller,<br />

Chalmers University of Technology, Sweden, M. Odén, L. Hultman,<br />

Linköping University, Sweden<br />

The ZrAlN system has recently come under investigation [1] as a system<br />

that has an even larger miscibility gap than TiAlN, as well as a large lattice<br />

mismatch between ZrN and AlN. Atom probe tomography was performed<br />

on magnetron sputtered epitaxial Zr0.64Al0.36N thin films grown on<br />

MgO(001) substrates kept at 800 °C. A self-organized nanostructure was<br />

resolved, consisting of lamellae of Zr(Al)N and Al(Zr)N with a<br />

characteristic length scale of ~4 nm in the film plane and extending in the<br />

growth direction. In addition, Al was found to segregate to the<br />

film/substrate interface, forming a 1 nm thick layer. This was followed by<br />

growth of a 4 nm thick Al-depleted zone, self-organization of the Zr(Al)N<br />

and Al(Zr)N lamellas during 5 nm film growth, and finally steady-state<br />

growth of the lamellar structure.<br />

[1] L. Rogström, L.J.S. Johnson, M.P. Johansson, M. Ahlgren, L. Hultman,<br />

and M. Odén<br />

Scripta Materialia 62 (2010) 739-741<br />

11:00am TS2-1-4 3D FIB/SEM imaging and 3D EBSD analysis of<br />

compressed MgO micropillars, M. Ritter (ritter@tu-harburg.de),<br />

Hamburg University of Technology, Germany, S. Korte, W.J. Clegg, P.A.<br />

Midgley, University of Cambridge, UK<br />

The application of FIB/SEM (focused ion beam/scanning electron<br />

microscope) instruments is rapidly expanding. This is in part due to the fact<br />

that there is a pressing need to understand the structure, composition and<br />

physico-chemical properties of modern materials in three dimensions. FIB<br />

instruments can unveil sub-surface structural information by creating crosssections<br />

that can easily be imaged or analysed [1]; and serial crosssectioning<br />

expands the instrument’s capabilities to the third dimension.<br />

In the process of serial sectioning, small and thin slices of material are<br />

removed in bulk samples by means of FIB milling, creating a series of<br />

cross-sections in one direction of the sample. State of the art FIB/SEM<br />

instruments provide a focused ion beam with small spot sizes so that slices<br />

that are only a few nanometres thick can be removed from the bulk material.<br />

Monday Morning, April 23, <strong>2012</strong> 8<br />

Each cross-section can then be imaged and the crystal orientations retrieved<br />

by Electron Backscatter Diffraction (EBSD) [2]. The information can then<br />

be reconstructed and combined to provide a comprehensive dataset for 3D<br />

orientation analysis.<br />

One of the manifold applications is the possibility of characterising plastic<br />

deformation in brittle materials due the suppression of cracking in very<br />

small bodies. We used 3D EBSD as a way of characterising the threedimensional<br />

(3-D) deformation at high spatial resolution of MgO<br />

micropillars compressed ex situ along two crystal directions [3]. We show<br />

that for a successful 3D reconstruction of the indexed crystal orientations it<br />

is necessary to use the SEM images as reference to correct for offsets. It is<br />

also shown that for the reconstruction of compressed and then successively<br />

sliced and indexed MgO micropillars, this 3D technique yields information<br />

complementary to µ-Laue diffraction or electron microscopy, allowing a<br />

correlation of experimental artefacts and the distribution of plasticity.<br />

References<br />

[1] L. A. Gianuzzi et al., Introduction to Focused Ion Beams. Springer, New<br />

York, 2005.<br />

[2] S. Zaefferer et al., Mater. Sci. Forum 495-497 (2005) 3.<br />

[3] S. Korte et al., Acta Mater. 59 (2011) 7241.<br />

11:20am TS2-1-5 Recent Advances in XPS for the Characterization of<br />

Thin Films, D. Surman (dsurman@kratos.com), Kratos Analytical Inc.,<br />

UK, C. Blomfield, A. Roberts, S. Hutton, S. Page, Kratos Analytical Ltd.,<br />

UK<br />

X-ray photoelectron spectroscopy is the most widely applied of a range of<br />

surface analysis techniques. Small area analysis from an area of a few<br />

microns and imaging XPS with spatial resolution of a few microns is now<br />

common place. 1 The advent of small analysis area XPS heralded an era for<br />

XPS depth profiling where a sputter crater is formed by an ion beam<br />

(typically Ar) and then XPS analysis formed in the crater. In such a way<br />

thin films of up to 1-2 microns in thickness can be analysed. XPS depth<br />

profiles can therefore elucidate the chemical composition of a thin film with<br />

a depth resolution of a few nanometers . XPS can analyse films and<br />

substrate materials which are either insulating or conductive. An important<br />

factor in the characterization of thin films is the understanding of the<br />

chemistry of the various layers as well as the interfacial chemistry. In order<br />

to get a better understanding of this, non-destructive methods (chemically<br />

rather than necessarily materially) have been refined such as Angle<br />

Resolved XPS and the application of advanced mathematical modelling<br />

such as MEMS algorithms have enhanced the information that can be<br />

extracted. This technique has become especially powerful for very thin<br />

films.<br />

Other recent developments have focussed on improved ion gun design, by<br />

lowering the Ar ion energy improved interface resolution is possible. To<br />

date, XPS depth profiling has been principally applied to inorganic<br />

materials but the recent development of polyatomic ion guns using large<br />

carbon based molecules such as Fullerene or Coronene has expanded XPS<br />

depth profiling into organic materials 2 .<br />

Examples will be given here which describe the state of the art in XPS<br />

depth profiling utilizing both ARXPS and MEMS as well as chemically<br />

non-destructive profiling with Polyatomic ion species on both organic and<br />

inorganic materials. Examples of nanometer depth resolution and<br />

quantitative chemical composition of films of several hundred nanometers<br />

in thickness from a range of applications will be given.<br />

1. C.J. Blomfield, Journal of Electron Spectroscopy and Related Phenomena<br />

143 (2005) 41-249<br />

2. G.X. Biddulph, A. M. Piwowar, J.S. Fletcher, N.P. Lockyer, J. C.<br />

Vickerman, Anal, Chem, 79, (2007), 7259-7266.

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