Topographic and material contrast in low‐voltage scanning electron microscopy

Hejna, J.

doi:10.1002/sca.4950170607

Cited by 16 publications

(11 citation statements)

References 23 publications

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“…This is why, topography is a major effect that needs to be taken into account when interpreting experimental SEM pseudocolour images. Seen from a different perspective, the diffraction effects can also limit the sensitivity of methods to determine the local surface topography via angle‐resolved detection of the backscattered electron distribution (Hejna, , ; Picard et al ., ; Zaefferer & Elhami, ; Wright et al ., ; Chapman et al ., ). If the local changes of the topographic surface plane inclination angle are in the order of the effects due to incident beam diffraction, it can be challenging to disentangle both effects in the angle‐dependent BSE intensity observed.…”

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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“…Furthermore, when increasing the incident angle of the electron beam, we find P th of the facet decreases and displays less than 2% deviation from the CASINO simulation, as shown in Figure 3j. However, as shown in the inset of Figure 3j, the poor S/N and the limited solid angle of the SE detector make it difficult to collect all electrons and the corresponding effect of tilting in SE, as well as in BSE, 34 is hard to analyze quantitatively.…”

Section: ■ Resultsmentioning

confidence: 99%

Scanning Electron Thermal Absorbance Microscopy for Light Element Detection and Atomic Number Analysis

et al. 2022

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Recent developments in nanoscale thermal metrology using electron microscopy have made impressive advancements in measuring either phononic or thermal transport properties of nanoscale samples. However, its potential in material analysis has never been considered. Here we introduce a direct thermal absorbance measurement platform in scanning electron microscope (SEM) and demonstrate that its signal can be utilized for atomic number (Z) analysis at nanoscales. We prove that the measured absorbance of materials is complementary to signals of backscattering electrons but exhibits a much higher collection efficiency and signal-to-noise ratio. Thus, it not only enables successful detections of light elements/ compounds under low acceleration voltages of SEM but also allows quantitative Z analyses in agreement with simulations. The direct thermal absorbance measurement platform would become an ideal tool for SEM, especially for thin films, light elements/compounds, or biological samples at nanoscales.

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“…Since the 1990's, SEM developments have mainly advanced in two directions: low‐voltage performance (Joy and Joy, ; Müllerová and Frank, ; Cazaux, ) and the capability to work in low vacuums (Stokes, ; Pawley and Schatten, ). There are many advantages in performing SEM operations at low voltages: increased yields of SEs (Lin and Joy, ), higher spatial resolution as a result of the reduced electron‐solid interaction volumes (Joy and Joy, ), high composition contrast stemming from larger differences in the secondary electron yield between different elements (Joy and Joy, ), high orientation contrast (Aoyama et al ., ), high electronic contrast in semiconductors (Perovic et al ., ; Müllerová et al ., ), lessening specimen charging for non‐conductive specimens (Joy and Joy, ; Png, ), and better topographic information (Hejna, ). The reduced interaction volume also increases the spatial resolution for EDS/wavelength‐dispersive spectroscopy (WDS) (Newbury, ; McSwiggen et al ., ; Schwandt, ) and EBSD (Steinmetz and Zaefferer, ).…”

Section: Recent Advances In Semmentioning

confidence: 99%

Information or resolution: Which is required from an SEM to study bulk inorganic materials?

Xing

2016

Scanning

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Significant technological advances in scanning electron microscopy (SEM) have been achieved over the past years. Different SEMs can have significant differences in functionality and performance. This work presents the perspectives on selecting an SEM for research on bulk inorganic materials. Understanding materials demands quantitative composition and orientation information, and informative and interpretable images that reveal subtle differences in chemistry, orientation/structure, topography, and electronic structure. The capability to yield informative and interpretable images with high signal-to-noise ratios and spatial resolutions is an overall result of the SEM system as a whole, from the electron optical column to the detection system. The electron optical column determines probe performance. The roles of the detection system are to capture, filter or discriminate, and convert signal electrons to imaging information. The capability to control practical operating parameters including electron probe size and current, acceleration voltage or landing voltage, working distance, detector selection, and signal filtration is inherently determined by the SEM itself. As a platform for various accessories, e.g. an energy-dispersive spectrometer and an electron backscatter diffraction detector, the properties of the electron optical column, specimen chamber, and stage greatly affect the performance of accessories. Ease-of-use and ease-of-maintenance are of practical importance. It is practically important to select appropriate test specimens, design suitable imaging conditions, and analyze the specimen chamber geometry and dimensions to assess the overall functionality and performance of an SEM. For an SEM that is controlled/operated with a computer, the stable software and user-friendly interface significantly improve the usability of the SEM. SCANNING 38:864-879, 2016. © 2016 Wiley Periodicals, Inc.

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Topographic and material contrast in low‐voltage scanning electron microscopy

Cited by 16 publications

References 23 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

Scanning Electron Thermal Absorbance Microscopy for Light Element Detection and Atomic Number Analysis

Information or resolution: Which is required from an SEM to study bulk inorganic materials?

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