Future Prospects for Defect and Strain Analysis in the SEM via Electron Channeling

Picard, Yoosuf N.; Kamaladasa, Ranga; Graef, Marc De; Nuhfer, Noel T.; Mershon, William; Owens, Tony; Sedláček, L.; Lopour, F.

doi:10.1017/s1551929512000077

Cited by 27 publications

(20 citation statements)

References 18 publications

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“…In order to reveal the different information content of various data visualizations, we analysed a sample of a GaN thin film containing dislocations. This example is also relevant to the important topic of contrast interpretation in SEM‐based dislocation imaging (Wilkinson & Hirsch, ; Picard et al ., ; Naresh‐Kumar et al ., ; Picard et al ., ; Zaefferer & Elhami, ).…”

Section: Resultsmentioning

confidence: 99%

Diffraction effects and inelastic electron transport in angle‐resolved microscopic imaging applications

Winkelmann

Nolze

Vespucci

et al. 2017

Journal of Microscopy

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SummaryWe analyse the signal formation process for scanning electron microscopic imaging applications on crystalline specimens. In accordance with previous investigations, we find nontrivial effects of incident beam diffraction on the backscattered electron distribution in energy and momentum. Specifically, incident beam diffraction causes angular changes of the backscattered electron distribution which we identify as the dominant mechanism underlying pseudocolour orientation imaging using multiple, angle-resolving detectors. Consequently, diffraction effects of the incident beam and their impact on the subsequent coherent and incoherent electron transport need to be taken into account for an in-depth theoretical modelling of the energy-and momentum distribution of electrons backscattered from crystalline sample regions. Our findings have implications for the level of theoretical detail that can be necessary for the interpretation of complex imaging modalities such as electron channelling contrast imaging (ECCI) of defects in crystals. If the solid angle of detection is limited to specific regions of the backscattered electron momentum distribution, the image contrast that is observed in ECCI and similar applications can be strongly affected by incident beam diffraction and topographic effects from the sample surface. As an application, we demonstrate characteristic changes in the resulting images if different properties of the backscattered electron distribution are used for the analysis of a GaN thin film sample containing dislocations.

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Section: Resultsmentioning

confidence: 99%

Diffraction effects and inelastic electron transport in angle‐resolved microscopic imaging applications

Winkelmann

Nolze

Vespucci

et al. 2017

Journal of Microscopy

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“…The simulations were carried out using a dynamical scattering model based on the scattering matrix formalism, 24 with straight 60 dislocations parallel to the sample surface at a depth of 50 nm, for the Burgers vectors indicated in the figure; details about the simulation approach will appear in a forthcoming paper, but reports on similar modeling can be found for other materials systems. 1 Each simulated ECCI image has the same diffraction condition as the experimental image to its left. Comparing the two sets of images shows good agreement between the corresponding experimental and simulated ECCI images.…”

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confidence: 99%

Rapid misfit dislocation characterization in heteroepitaxial III-V/Si thin films by electron channeling contrast imaging

Carnevale

Deitz

Carlin

et al. 2014

Applied Physics Letters

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Electron channeling contrast imaging (ECCI) is used to characterize misfit dislocations in heteroepitaxial layers of GaP grown on Si(100) substrates. Electron channeling patterns serve as a guide to tilt and rotate sample orientation so that imaging can occur under specific diffraction conditions. This leads to the selective contrast of misfit dislocations depending on imaging conditions, confirmed by dynamical simulations, similar to using standard invisibility criteria in transmission electron microscopy (TEM). The onset and evolution of misfit dislocations in GaP films with varying thicknesses (30 to 250 nm) are studied. This application simultaneously reveals interesting information about misfit dislocations in GaP/Si layers and demonstrates a specific measurement for which ECCI is preferable versus traditional plan-view TEM.

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“…In particular, the features revealed by this improved precision are shown to be dislocations by comparison with high resolution ECCI and it is shown that it is possible to quantify the misorientations around such features. The ECCI signal (Wilkinson & Hirsch, 1997; Crimp et al ., 2001; Trager‐Cowan et al ., 2007; Picard et al ., 2012; Mansour et al ., 2014; Zaefferer & Elhami, 2014; Guyon et al ., 2015) is produced when a sample is placed so that a crystal plane or planes are at, or close to, the Bragg angle with respect to the incident electron beam. Any deviation in crystallographic orientation or in lattice constant due to local strain will produce a variation in contrast in the resultant ECCI micrograph.…”

Section: Introductionmentioning

confidence: 99%

Improving EBSD precision by orientation refinement with full pattern matching

Winkelmann

Jablon

Tong

et al. 2020

Journal of Microscopy

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Summary We present a comparison of the precision of different approaches for orientation imaging using electron backscatter diffraction (EBSD) in the scanning electron microscope. We have used EBSD to image the internal structure of WC grains, which contain features due to dislocations and subgrains. We compare the conventional, Hough‐transform based orientation results from the EBSD system software with results of a high‐precision orientation refinement using simulated pattern matching at the full available detector resolution of 640 × 480 pixels. Electron channelling contrast imaging (ECCI) is used to verify the correspondence of qualitative ECCI features with the quantitative orientation data from pattern matching. For the investigated sample, this leads to an estimated pattern matching sensitivity of about 0.5 mrad (0.03°) and a spatial feature resolution of about 100 nm. In order to investigate the alternative approach of postprocessing noisy orientation data, we analyse the effects of two different types of orientation filters. Using reference features in the high‐precision pattern matching results for comparison, we find that denoising of orientation data can reduce the spatial resolution, and can lead to the creation of orientation artefacts for crystallographic features near the spatial and orientational resolution limits of EBSD.

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Future Prospects for Defect and Strain Analysis in the SEM via Electron Channeling

Cited by 27 publications

References 18 publications

Diffraction effects and inelastic electron transport in angle‐resolved microscopic imaging applications

Diffraction effects and inelastic electron transport in angle‐resolved microscopic imaging applications

Rapid misfit dislocation characterization in heteroepitaxial III-V/Si thin films by electron channeling contrast imaging

Improving EBSD precision by orientation refinement with full pattern matching

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