Robust Local Thickness Estimation of Sub-Micrometer Specimen by 4D-STEM

0579321 - ÚPT 2024 RIV US eng J - Journal Article
Skoupý, Radim - Boltje, D. B. - Šlouf, Miroslav - Mrázová, Kateřina - Láznička, Tomáš - Taisne, C. M. - Krzyžánek, Vladislav - Hoogenboom, J. P. - Jakobi, A. J.
Robust Local Thickness Estimation of Sub-Micrometer Specimen by 4D-STEM.
Small Methods. Roč. 7, č. 9 (2023), č. článku 2300258. ISSN 2366-9608. E-ISSN 2366-9608
R&D Projects: GA ČR(CZ) GA21-13541S; GA TA ČR(CZ) TN01000008
Institutional support: RVO:68081731 ; RVO:61389013
Keywords : 4D-STEM * cryo-ET * FIB milling * TEM analysis
OECD category: Electrical and electronic engineering; Atomic, molecular and chemical physics (physics of atoms and molecules including collision, interaction with radiation, magnetic resonances, Mössbauer effect) (UMCH-V)
Impact factor: 12.4, year: 2022
Method of publishing: Open access
https://onlinelibrary.wiley.com/doi/10.1002/smtd.202300258

A quantitative four-dimensional scanning transmission electron microscopy (4D-STEM) imaging technique (q4STEM) for local thickness estimation across amorphous specimen such as obtained by focused ion beam (FIB)-milling of lamellae for (cryo-)TEM analysis is presented. This study is based on measuring spatially resolved diffraction patterns to obtain the angular distribution of electron scattering, or the ratio of integrated virtual dark and bright field STEM signals, and their quantitative evaluation using Monte Carlo simulations. The method is independent of signal intensity calibrations and only requires knowledge of the detector geometry, which is invariant for a given instrument. This study demonstrates that the method yields robust thickness estimates for sub-micrometer amorphous specimen using both direct detection and light conversion 2D-STEM detectors in a coincident FIB-SEM and a conventional SEM. Due to its facile implementation and minimal dose reauirements, it is anticipated that this method will find applications for in situ thickness monitoring during lamella fabrication of beam-sensitive materials.
Permanent Link: https://hdl.handle.net/11104/0348160