Materials characterisation by angle-resolved scanning transmission electron microscopy
| Autor: | Marco Schowalter, Florian F. Krause, Knut Müller-Caspary, Thorsten Mehrtens, Andreas Beyer, Pavel Potapov, Tim Grieb, Kerstin Volz, Oliver Oppermann, Andreas Rosenauer |
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| Rok vydání: | 2016 |
| Předmět: |
010302 applied physics
Conventional transmission electron microscope Multidisciplinary Materials science business.industry Scanning confocal electron microscopy 02 engineering and technology Inelastic scattering 021001 nanoscience & nanotechnology 01 natural sciences Article Optics 0103 physical sciences Scanning transmission electron microscopy ddc:000 Scanning ion-conductance microscopy Energy filtered transmission electron microscopy Angular resolution 0210 nano-technology business Electron scattering |
| Zdroj: | Scientific Reports Scientific reports 6, 37146 (2016). doi:10.1038/srep37146 |
| ISSN: | 2045-2322 |
| Popis: | Solid-state properties such as strain or chemical composition often leave characteristic fingerprints in the angular dependence of electron scattering. Scanning transmission electron microscopy (STEM) is dedicated to probe scattered intensity with atomic resolution, but it drastically lacks angular resolution. Here we report both a setup to exploit the explicit angular dependence of scattered intensity and applications of angle-resolved STEM to semiconductor nanostructures. Our method is applied to measure nitrogen content and specimen thickness in a GaNxAs1−x layer independently at atomic resolution by evaluating two dedicated angular intervals. We demonstrate contrast formation due to strain and composition in a Si- based metal-oxide semiconductor field effect transistor (MOSFET) with GexSi1−x stressors as a function of the angles used for imaging. To shed light on the validity of current theoretical approaches this data is compared with theory, namely the Rutherford approach and contemporary multislice simulations. Inconsistency is found for the Rutherford model in the whole angular range of 16–255 mrad. Contrary, the multislice simulations are applicable for angles larger than 35 mrad whereas a significant mismatch is observed at lower angles. This limitation of established simulations is discussed particularly on the basis of inelastic scattering. |
| Databáze: | OpenAIRE |
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