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The Probe Profile and Lateral Resolution of Scanning Transmission Electron Microscopy of Thick Specimens

Published online by Cambridge University Press:  08 May 2012

Hendrix Demers ,
Ranjan Ramachandra ,
Dominique Drouin  and
Niels de Jonge
Hendrix Demers
Affiliation:
Universite de Sherbrooke, Electrical and Computer Engineering Department, Sherbrooke, Quebec J1K 2R1, Canada
Ranjan Ramachandra
Affiliation:
Vanderbilt UniversitySchool of Medicine, Department of Molecular Physiology and Biophysics, Nashville, TN 37232-0615, USA
Dominique Drouin
Affiliation:
Universite de Sherbrooke, Electrical and Computer Engineering Department, Sherbrooke, Quebec J1K 2R1, Canada
Niels de Jonge*
Affiliation:
Vanderbilt UniversitySchool of Medicine, Department of Molecular Physiology and Biophysics, Nashville, TN 37232-0615, USA
*
Corresponding author. E-mail: [email protected]
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Abstract

Lateral profiles of the electron probe of scanning transmission electron microscopy (STEM) were simulated at different vertical positions in a micrometers-thick carbon sample. The simulations were carried out using the Monte Carlo method in CASINO software. A model was developed to fit the probe profiles. The model consisted of the sum of a Gaussian function describing the central peak of the profile and two exponential decay functions describing the tail of the profile. Calculations were performed to investigate the fraction of unscattered electrons as a function of the vertical position of the probe in the sample. Line scans were also simulated over gold nanoparticles at the bottom of a carbon film to calculate the achievable resolution as a function of the sample thickness and the number of electrons. The resolution was shown to be noise limited for film thicknesses less than 1 μm. Probe broadening limited the resolution for thicker films. The validity of the simulation method was verified by comparing simulated data with experimental data. The simulation method can be used as quantitative method to predict STEM performance or to interpret STEM images of thick specimens.

Keywords

electron probe broadeningMonte Carlo simulationsnanoparticlesnoise-limited resolutionSTEMspatial resolutionthick specimen
Type
Materials Applications
Information
Microscopy and Microanalysis , Volume 18 , Issue 3 , June 2012 , pp. 582 - 590
Copyright
Copyright © Microscopy Society of America 2012

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References

Czyzewski, Z., MacCullum, D.O.N., Romig, A. & Joy, D.C. (1990). Calculation of Mott scattering cross section. J Appl Phys 68(7), 3066–3072.CrossRefGoogle Scholar
de Jonge, N., Peckys, D.B., Kremers, G.J. & Piston, D.W. (2009). Electron microscopy of whole cells in liquid with nanometer resolution. PNAS 106, 2159–2164.CrossRefGoogle ScholarPubMed
de Jonge, N., Poirier-Demers, N., Demers, H., Peckys, D.B. & Drouin, D. (2010). Nanometer-resolution electron microscopy through micrometers-thick water layers. Ultramicroscopy 110, 1114–1119.CrossRefGoogle ScholarPubMed
Demers, H., Poirier-Demers, N., Drouin, D. & de Jonge, N. (2010). Simulating STEM imaging of nanoparticles in micrometers-thick substrates. Microsc Microanal 16, 795–804.CrossRefGoogle ScholarPubMed
Doig, P. & Flewitt, P. (1982). The detection of monolayer grain boundary segregations in steels using STEM-EDS X-ray microanalysis. Metall Mater Trans A 13, 1397–1403.CrossRefGoogle Scholar
Doig, P., Lonsdale, D. & Flewitt, P. (1981). X-ray microanalysis of grain boundary segregations in steels using the scanning transmission electron microscope. Metall Mater Trans A 12, 1277–1282.CrossRefGoogle Scholar
Gentsch, P., Gilde, H. & Reimer, L. (1974). Measurement of the top bottom effect in scanning transmission electron microscopy of thick amorphous specimens. J Microsc 100, 81–92.CrossRefGoogle Scholar
Groves, T. (1975). Thick specimens in the CEM and STEM. Resolution and image formation. Ultramicroscopy 1(1), 15–31.CrossRefGoogle ScholarPubMed
Hall, E., Imeson, D. & Sande, J.B.V. (1981). On producing high-spatial-resolution composition profiles via scanning transmission electron microscopy. Philos Mag A 43, 1569–1585.CrossRefGoogle Scholar
Hyun, J.K., Ercius, P. & Muller, D.A. (2008). Beam spreading and spatial resolution in thick organic specimens. Ultramicroscopy 109, 1–7.CrossRefGoogle ScholarPubMed
Jablonski, A., Salvat, F. & Powell, C.J. (2003). NIST Electron Elastic-Scattering Cross-Section Database—Version 3.1. Gaithersburg, MD: National Institute of Standards and Technology.Google Scholar
Loos, J., Sourty, E., Lu, K., Freitag, B., Tang, D. & Wall, D. (2009). Electron tomography on micrometer-thick specimens with nanometer resolution. Nano Lett 9, 1704–1708.CrossRefGoogle ScholarPubMed
Michael, J.R. & Williams, D.B. (1987). A consistent definition of probe size and spatial resolution in the analytical electron microscope. J Microsc 147, 289–303.CrossRefGoogle Scholar
Miyazawa, A., Fujiyoshi, Y. & Unwin, N. (2003). Structure and gating mechanism of the acetylcholine receptor pore. Nature 423, 949.CrossRefGoogle ScholarPubMed
Mott, N.F. & Massey, H.S.W. (1965). The Theory of Atomic Collisions. London: Oxford University Press.Google Scholar
Press, W.H., Teukolsky, S.A., Vetterling, W.T. & Flannery, B.P. (2002). Numerical Recipes in C++: The Art of Scientific Computing. Cambridge, UK: The Press Syndicate of the University of Cambridge.Google Scholar
Ramachandra, R., Demers, H. & de Jonge, N. (2011). Atomic-resolution scanning transmission electron microscopy through 50 nm-thick silicon nitride membranes. Appl Phys Lett 98, 93109-1–3.CrossRefGoogle ScholarPubMed
Reed, S.J.B. (1982). The single-scattering model and spatial resolution in X-ray analysis of thin foils. Ultramicroscopy 7, 405–410.CrossRefGoogle Scholar
Reimer, L. & Kohl, H. (2008). Transmission Electron Microscopy: Physics of Image Formation. Berlin, New York: Springer.Google Scholar
Rez, P. (1983). A transport equation theory of beam spreading in the electron microscope. Ultramicroscopy 12, 29–38.CrossRefGoogle Scholar
Rose, A. (1948a). The sensitivity performance of the human eye on an absolute scale. J Opt Soc Am 38, 196–208.CrossRefGoogle Scholar
Rose, A. (1948b). Television pickup tubes and the problem of noise. Adv Electron 1, 131–166.Google Scholar
Salvat, F., Jablonski, A. & Powell, C.J. (2005). ELSEPA—Dirac partial-wave calculation of elastic scattering of electrons and positrons by atoms, positive ions and molecules. Comput Phys Commun 165, 157–190.CrossRefGoogle Scholar
Sousa, A.A., Hohmann-Marriott, M., Aronova, M.A., Zhang, G. & Leapman, R.D. (2008). Determination of quantitative distributions of heavy-metal stain in biological specimens by annular dark-field STEM. J Struct Biol 162, 14–28.CrossRefGoogle ScholarPubMed
Sousa, A.A., Hohmann-Marriott, M.F., Zhang, G. & Leapman, R.D. (2009). Monte Carlo electron-trajectory simulations in bright-field and dark-field STEM: Implications for tomography of thick biological sections. Ultramicroscopy 109, 213–221.CrossRefGoogle ScholarPubMed
Williams, D.B., Micheal, J.R., Goldstein, J.I. & Romig, A.D. Jr. (1992). Definition of the spatial resolution of X-ray microanalysis in thin foils. Ultramicroscopy 47, 121–132.CrossRefGoogle Scholar