Regensburg 2013 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 11: Topical Session: TEM-Symposium - STEM

MM 11.7: Vortrag

Montag, 11. März 2013, 17:30–17:45, H4

Analytical transmission electron microscopy in the third dimension — •Bert Freitag, Arda Genc, Jonathan Winterstein, Huikai Cheng, Lee Pullan, and Joerg Jinschek — FEI Company, Eindhoven, The Netherlands

As the feature sizes in material science continue to decrease to nanometer regime, the techniques solely based on 2-dimensional (2D) imaging fail to provide a full characterization of the nanoscale materials. We employed a new tomography technique for STEM XEDS which utilizes the combination of a four silicon drift detector (SDD) system and a high brightness electron gun (XFEG) optimized for high X-ray collection efficiency [1]. Three dimensional tomograms are obtained when the sample is tilted and images and EDS maps are acquired from all angles. The EDS signal can be processed like normal z-contrast images since the EDS signal increases monotonously with the concentration of the element like z-contrast signal increases monotonously with the mass thickness. Examples of 3D chemical mapping using XEDS are given on (InGa)N Nanopyramid LEDs, NiAl3 super alloy material for aircraft turbine blades, high-k dielectric transistor and catalytic particles. In summary, this new technique enables a larger field of view and reduces the acquisition time of a complete XEDS mapping tilt series to hours instead of days, which were impractical before. Even the use of conventionally prepared FIB foils for 3D chemical mapping is possible, which overcomes the difficulties related to background changes with thickness increase known in EELS. [1] P. Schlossmacher et al., Microscopy Today 18(4) (2010) 14-20.