Showing papers on "Electron tomography published in 2003"
TL;DR: Examples of how STEM dark-field imaging and energy-filtered TEM can be used successfully to examine nearly all types of specimens likely to be encountered by the physical scientist are presented.
956 citations
TL;DR: The elemental mapping techniques in analytical transmission electron microscopy, energy filtered imaging and EDX-mapping, are shown to provide new routes for tomographic reconstructions of 3D chemical maps on the nanoscale and the inelastic scattering improves the linear projection relationship between mass density and image intensity.
162 citations
TL;DR: In this article, small gold and zirconia particles inside the mesopores of SBA-15 were visualized with bright-field electron tomography, which explains the two-step desorption isotherm in nitrogen physisorption experiments.
Abstract: Small gold (5 nm) and zirconia (2−3 nm) particles inside the mesopores of SBA-15 were visualized with bright-field electron tomography. Due to the ordered nature of the mesopores and the related diffraction contrast present in the tilt series, the 3D-reconstruction is difficult to interpret. Unequivocal information has been obtained, however, on the presence of the particles in certain pores, while others pores are empty. This nonuniform distribution of particles over the mesopores explains the two-step desorption isotherm in nitrogen physisorption experiments.
109 citations
TL;DR: In this paper, the authors present a model to explain the shapes of structures grown by electron-beam-induced deposition (EBID) and also predict the possibility to directly fabricate structures with lateral sizes smaller than 10 nm.
Abstract: Electron-beam-induced deposition (EBID) is a potentially fast and resistless deposition technique which might overcome the fundamental resolution limits of conventional electron-beam lithography. We advance the understanding of the EBID process by simulating the structure growth. The merit of our model is that it explains the shapes of structures grown by EBID quantitatively. It also predicts the possibility to directly fabricate structures with lateral sizes smaller than 10 nm and points out the ideal conditions to achieve this goal. We verify these predictions by fabricating sub-10-nm lines and dots in a state-of-the-art scanning transmission electron microscope.
105 citations
TL;DR: In this article, a high-speed transmission electron microscope was developed for probing laser-induced fast nonperiodical processes on the nanosecond time scale, which can be used for experiments on thin films.
Abstract: A high-speed transmission electron microscope was developed for probing laser-induced fast nonperiodical processes on the nanosecond time scale. 7–11 ns illuminating electron pulses—up to three—are produced by a laser pulse-driven photocathode. The electron gun can be used both for nanosecond exposure and conventional stationary operation. The introduced microscope is operated in three different modes for investigations of laser treated thin films: (1) Bright-field imaging, tracking changes of the texture and transport of neutral material; (2) dark-field imaging, mapping transient plasmas; and (3) selected area diffraction to study fast phase transitions. Presently, the space resolution is ≈200 nm.
98 citations
97 citations
TL;DR: In this paper, the final state of the material resulting from laser irradiation of silicon using 130 fs pulses at 790 nm was studied using a number of techniques including scanning and transmission electron microscopies, as well as atomic force microscopy.
Abstract: The final state of the material resulting from laser irradiation of silicon using 130 fs pulses at 790 nm was studied using a number of techniques including scanning and transmission electron microscopies, as well as atomic force microscopy. Structural details and the level of damage to the nearby solid following irradiation were characterized and are discussed in the context of recent dynamical studies.
92 citations
TL;DR: Cryo-tomograms of Dictyostelium cells depict distinct populations of ribosomes, proteasomes and networks of actin filaments interconnected by branching or bundling, apparently controlled by strategically placed actin-associated proteins.
75 citations
TL;DR: It is concluded that the image contrast, signal, and signal-to-noise ratio (SNR) are key to the achievable reconstruction quality and, as such, the technique may be of limited value for high energy loss/small inelastic cross section edges.
Abstract: The length scales on which materials microstructures are being formed, grown, and even designed are becoming increasingly small and increasingly three-dimensional. For such complex structures two-dimensional transmission electron microscopy (TEM) analysis is often inadequate and occasionally misleading. One approach to this problem is the modification of electron tomography techniques, developed for structural biology, for use in materials science. Energy-Filtered (EF) TEM elemental distribution images approximate to true projections of structure, and, as such, can be used to reconstruct the three-dimensional distribution of chemical species. A sample holder has been modified to allow the high tilt (+/-60 degrees ) required for tomography and a semiautomatic acquisition script designed to manage energy-loss acquisition. Tilt series data sets have been acquired from two widely different experimental systems, Cr carbides in 316 stainless steel and magnetite nanocrystals in magnetotactic bacteria, demonstrating single- and multiple-element tomography. It is shown that both elemental maps and jump-ratio images are suitable for reconstruction, despite the effects of diffraction contrast in the former and thickness changes in the latter. It is concluded that the image contrast, signal, and signal-to-noise ratio (SNR) are key to the achievable reconstruction quality and, as such, the technique may be of limited value for high energy loss/small inelastic cross section edges.
61 citations
TL;DR: A new electron microscopic approach to investigate individual molecular structures is introduced and the possibility for determining the molecular isomer on a single-molecular basis is demonstrated.
Abstract: Intramolecular structure of the scandium dimetallofullerene (Sc 2 @C 8 4 ) has been clearly revealed by high resolution transmission electron microscopy with the single-atom sensitivity. Direct observation of two Sc atoms inside each fullerene molecule has led to a successful determination of the molecular symmetry among the three possible structural isomers for the Sc 2 @C 8 4 . The present work introduces a new electron microscopic approach to investigate individual molecular structures and demonstrates the possibility for determining the molecular isomer on a single-molecular basis.
61 citations
TL;DR: In this article, a method of obtaining quantitative two-dimensional (2D) maps of strain by the convergent beam electron diffraction technique in a transmission electron microscope is described, based on the automatic acquisition of a series of diffraction patterns generated from digital rastering the electron spot in a matrix of points within a selected area of the sample.
Abstract: A method of obtaining quantitative two-dimensional (2D) maps of strain by the convergent beam electron diffraction technique in a transmission electron microscope is described. It is based on the automatic acquisition of a series of diffraction patterns generated from digital rastering the electron spot in a matrix of points within a selected area of the sample. These patterns are stored in a database and the corresponding strain tensor at each point is calculated, thus yielding a 2D strain map. An example of application of this method to cross-sectioned cells fabricated for the 0.15 μm technology of flash memories is reported.
Book•
01 Jan 2003
TL;DR: Theoretical foundations of transmission electron microscopy have been discussed in this paper, where In0.6Ga0.4As/GaAs(001) SK Layers and InAs Quantum Dots are used.
Abstract: Theoretical Fundamentals of Transmission Electron Microscopy.- Electron Diffraction.- Image Formation.- Digital Image Analysis.- Strain State Analysis.- Lattice Fringe Analysis.- Applications.- In0.6Ga0.4As/GaAs(001) SK Layers.- InAs Quantum Dots.- Electron Holography: AlAs/GaAs Superlattices.- Outlook.
TL;DR: The performance of the camera is satisfactory under the low-dose conditions used in cryo electron microscopy, as demonstrated here by the determination of a three-dimensional map at 15 A for the catalytic core of the 1.8 MDa Bacillus stearothermophilus icosahedral pyruvate dehydrogenase complex.
TL;DR: In this article, a pathway from microcharacterization to macroscopic properties of materials is discussed on metal/ceramic composites and an assessment of the properties of these materials is presented.
Patent•
17 Jan 2003TL;DR: In this article, a scanning transmission electron microscope (STEM) has an electron source for generating a primary electron beam and an electron illuminating lens system for converging the electron beam from the electron source onto a specimen for illumination.
Abstract: A scanning transmission electron microscope (STEM) has an electron source for generating a primary electron beam and an electron illuminating lens system for converging the primary electron beam from the electron source onto a specimen for illumination. An electron deflecting system is provided for scanning the specimen with the primary electron beam. The STEM also has a scattered electron detector for detecting scattered electrons transmitted through the specimen. A projection lens system projects the scattered electrons onto a detection surface of the scattered electron detector. An image displaying device displays the scanning transmission electron microscope image of the specimen using a detection signal from the scattered electron detector. A detection angle changing device for establishes the range of the scattering angle of the scattered electrons detected by the scattered electron detector. This structure enhances the contrast of a desired portion of the specimen under observation for a scanning transmitted image by selective establishment of detection angle ranges for the scattered electron detector.
TL;DR: A combine correlative fluorescence microscopy with electron spectroscopic imaging (ESI) is described, so that elemental maps can be obtained, to permit delineation of specific biochemical features and provide an opportunity for the development of quantum dot and metaltagged probes for mapping proteins and other features with both high resolution and a high degree of detection sensitivity.
Abstract: Publisher Summary This chapter describes a combine correlative fluorescence microscopy with electron spectroscopic imaging (ESI), so that elemental maps can be obtained. These permit delineation of specific biochemical features and provide an opportunity for the development of quantum dot (Q-dot) and metaltagged probes for mapping proteins and other features with both high resolution and a high degree of detection sensitivity. Correlative light microscopy and ESI to study DNA–protein complexes including chromatin, visualized both in vitro and in situ . ESI or energy-filtered transmission electron microscopy is based on the principle of electron energy loss spectroscopy. When a specimen is bombarded with electrons, the elements within the specimen can become ionized, and the energy for that ionization event is equal to the energy lost by the incident electron responsible for that event. An imaging electron spectrometer produces an energy loss spectrum reflecting the elemental content of the sample and is capable of reconstituting an image with electrons that have lost a particular amount of energy. Because the technique is quantitative, ribonucleoprotein or chromatin structures can be identified in the electron micrographs based on their ratio of nitrogen to phosphorus.
TL;DR: In this paper, an aberration free microscope is used to resolve and refine amorphous structures at the atomic level for very small foil thicknesses, but this may require long recording times, especially for light atoms.
TL;DR: Detailed comparative in situ analyses strongly suggest the involvement of pKi-67 in the higher-order organization of perinucleolar chromatin.
Abstract: The monoclonal antibody (MAb) Ki-67 is routinely used in clinical studies to estimate the growth fraction of tumors. However, the role of pKi-67, the protein detected by the Ki-67 MAb, remains elusive, although some biochemical data strongly suggest that it might organize chromatin. To better understand the functional organization of pKi-67, we studied its three-dimensional distribution in interphase cells by confocal microscopy and electron tomography. FluoroNanogold, a single probe combining a dense marker with a fluorescent dye, was used to investigate pKi-67 organization at the optical and ultrastructural levels. Observation by confocal microscopy followed by 3D reconstruction showed that pKi-67 forms a shell around the nucleoli. Double labeling experiments revealed that pKi-67 co-localizes with perinucleolar heterochromatin. Electron microscopy studies confirmed this close association and demonstrated that pKi-67 is located neither in the fibrillar nor in the granular components of the nucleolus. Finally, spatial analyses by electron tomography showed that pKi-67 forms cords 250-300 nm in diameter, which are themselves composed of 30-50-nm-thick fibers. These detailed comparative in situ analyses strongly suggest the involvement of pKi-67 in the higher-order organization of perinucleolar chromatin.
TL;DR: A technique is described which can be used to identify a particular cell in the light microscope and then to embed and thin-section it for electron microscopy, to obtain images for 3D analysis of detail at the suborganelle level.
Abstract: Correlative imaging of a specific cell with both the light microscope and the electron microscope has proved to be a difficult task, requiring enormous amounts of patience and technical skill. We describe a technique with a high rate of success, which can be used to identify a particular cell in the light microscope and then to embed and thin-section it for electron microscopy. The technique also includes a method to obtain many uninterrupted, thin serial sections for imaging by conventional or energy-filtered transmission electron microscopy, to obtain images for 3D analysis of detail at the suborganelle level.
TL;DR: Experimental and theoretical results on image contrast of semiconductor multi-layers in scanning electron microscopy investigation are reported, finding that bright field images can be easily related to local variation in atomic number and density while the dark field image contrast is strongly affected by electron beam energy, detector collection angles and specimen thickness.
15 Feb 2003-Philosophical transactions - Royal Society. Mathematical, physical and engineering sciences
TL;DR: In this paper, high-resolution transmission electron microscopy was used to show that metal nanoparticles sinter within a fraction of a second under an electron beam at "room temperature" as long as classical models of thermal equilibrium apply.
Abstract: High-resolution transmission electron microscopy shows that metal nanoparticles sinter within a fraction of a second under an electron beam at 'room temperature' as long as classical models of thermal equilibrium apply. Images exhibit crystal planes that change in orientation with time as if the particle was undergoing melting and resolidification processes. We explore whether these dynamical effects are the result of heating or transformation effects in the electron microscope or quantum fluctuations in small systems.
TL;DR: In this article, a three-dimensional reconstruction of nano-scale objects (such as biological macromolecules) can be accomplished using data recorded with a transmission electron microscope using Chahine's method.
Abstract: Three-dimensional reconstruction of nano-scale objects (such as biological macromolecules) can be accomplished using data recorded with a transmission electron microscope An image obtained by a transmission electron microscope can be conceived of as an 'ideal' projection subjected to a contrast transfer function, which attenuates most frequencies, reverses the phase of others and even eliminates some of them Such instrumental aberrations make the problem of reconstruction from such data difficult We reformulate the problem so that Chahine's method becomes applicable to it We demonstrate the performance of our approach with numerical evidence using both simulated and actual electron microscopy data
TL;DR: In this paper, statistical experimental design is applied to set up quantitative atomic resolution transmission electron microscopy experiments to find the experimental settings resulting into the highest attainable precision, where the purpose of the proposed experimental design was to find a set of experimental settings that maximizes the achievable precision.
Abstract: Statistical experimental design is applied to set up quantitative atomic resolution transmission electron microscopy experiments. In such experiments, observations of the atomic structure of the object under study are always subject to spontaneous fluctuations. As a result of these fluctuations, the precision with which structure parameters can be measured is limited. The purpose of the proposed statistical experimental design is to find the experimental settings resulting into the highest attainable precision.
TL;DR: In this paper, the authors applied this technique for the first time to characterize Cu interconnect Ta-barrier/Cu-seed layer stacks deposited under different conditions, and their roughness and step coverage became clearly visible in the reconstructions.
TL;DR: This communication presents a method that can be used to improve the accuracy of the basic autofocusing procedures currently used in systems for automated electron tomography.
Abstract: Transmission electron microscopy images acquired under tilted-beam conditions experience an image shift as a function of defocus settings - a fact that is exploited as a method for defocus determination in most of the automated tomography data collection systems. Although the method was shown to be highly accurate for a large variety of specimens, we point out that in its original design it can strictly only be applied to images of untilted samples. The application to tilted samples and thus in automated electron tomography is impaired mainly due to a defocus change across the images, resulting in reduced accuracy. In this communication we present a method that can be used to improve the accuracy of the basic autofocusing procedures currently used in systems for automated electron tomography.
TL;DR: In this article, the authors presented tomographic reconstructions of simulated scans of a photonic band-gap crystal based on bright-field imaging with a scanning transmission electron microscope are made assuming (1) multiple scattering or (2) the standard Beer's Law model.
Abstract: To date, nearly all tomography based on electron microscopy has been performed on samples 1 μm or less thick. It has also relied on Beer’s Law. In this work, tomographic reconstructions of simulated scans of a photonic band-gap crystal based on bright-field imaging with a scanning transmission electron microscope are made assuming (1) multiple scattering or (2) the standard Beer’s Law model. The results suggest that it should be possible to treat systems several times larger than those which appear in literature, albeit at a worse resolution. The multiple scattering theory leads to high-quality reconstructions. Beer’s Law does only a little worse despite being applied outside its range of validity.
Patent•
02 Sep 2003
TL;DR: In this article, a device and method which enable a transmission electron microscope to measure electron diffraction patterns of a sample very precisely is disclosed, and the patterns are suitable for structure determination.
Abstract: A device and method which enable a transmission electron microscope to measure electron diffraction patterns of a sample very precisely are disclosed. The patterns are suitable for structure determination. The electron beam is precessed by means of deflector coils (6) in the transmission electron microscope before the sample (4), in combination with a similar precession of the electron diffraction pattern by means of deflector coils (9) situated after the sample. The electron diffraction pattern is scanned by means of deflector coils (9) situated after the sample.
TL;DR: In this paper, a plan-view transmission electron microscopy analysis was used to locate the failure site precisely using the in-situ lift-out technique in the focused ion beam machine.
Abstract: Cross-sectional transmission electron microscopy (TEM) analysis has become routinely used in semiconductor industry to support failure and yield analysis. Plan-view transmission electron microscopy analysis however is much less frequently performed. In this paper it is illustrated that plan-view transmission electron microscopy analysis can add valuable information in yield analysis studies, especially when crystal defects are involved. ‘3-Dimensional’ information can be obtained by combining cross-sectional transmission electron microscopy analysis with plan-view analysis. If the available material is limited, it can become a difficult choice whether to go for a cross-sectional or a plan-view analysis. Therefore it was explored if a cross-sectional specimen could still be made out of a plan-view specimen, using the plan-view analysis to locate the failure site precisely. This has recently been successfully done using the in-situ lift-out technique in the focused ion beam machine.
TL;DR: In this paper, simulation and experimental results for add-on transmission attachments that have been developed for the scanning electron microscope (SEM) are presented, where a primary beam energy of around 30 keV is used to irradiate thin test specimens (<100 nm).
Abstract: This article presents simulation and experimental results for add-on transmission attachments that have been developed for the scanning electron microscope (SEM). A primary beam energy of around 30 keV is used to irradiate thin test specimens (<100 nm). A transmission lens attachment enables a conventional field emission SEM to improve its image resolution by an order of magnitude, providing an image magnification of several million and a spatial resolution down to 0.3 nm. In addition, a compact energy electron loss spectrometer attachment has been developed that uses the SEM’s built-in secondary electron detector.
01 Jan 2003
TL;DR: In this article, the problem of reconstructing finite lattice sets from certain of their marginal sums was studied in high-resolution transmission electron microscopy (HRTEM) in a certain limited number of directions.
Abstract: The present paper is motivated by the demand from material sciences to reconstruct crystalline structures given through their images under high resolution transmission electron microscopy (HRTEM) in a certain limited number of directions. In particular, [31] and [22] show how a quantitative analysis of images from high resolution transmission electron microscopy can be used to determine the number of atoms on atomic columns in certain directions; see Sects. 2 and 3. Mathematically, this leads to the problem of reconstructing finite lattice sets from certain of their marginal sums; see Sect. 4.