Academic literature on the topic 'HIGH-RESOLUTION TRANSMISSION ELECTON MICROSCOPE'

Historically, ultra high spatial resolution electron microscopy has belonged to the transmission electron microscope. Today, however, ultra high resolution scanning electron microscopes are beginning to challenge the transmission microscope for the highest resolution.To accomplish high resolution surface imaging, not only is high resolution required. It is also necessary that the integrity of the specimen be preserved, i.e., that morphological changes to the specimen during observation are prevented. The two major artifacts introduced during observation are contamination and beam damage, both created by the small, high current-density probes necessary for high signal generation in the scanning instrument. The JSM-890 Ultra High Resolution Scanning Microscope provides the highest resolution probe attainable in a dedicated scanning electron microscope and its design also accounts for the problematical artifacts described above.Extensive experience with scanning transmission electron microscopes lead to the design considerations of the ultra high resolution JSM- 890.

Diagnostic electron microscopy is a useful technique for the identification of viruses associated with human, animal, or plant diseases. The size of virus structures requires a high optical resolution (i.e., about 1 nm), which, for a long time, was only provided by transmission electron microscopes operated at 60 kV and above. During the last decade, low-voltage electron microscopy has been improved and potentially provides an alternative to the use of high-voltage electron microscopy for diagnostic electron microscopy of viruses. Therefore, we have compared the imaging capabilities of three low-voltage electron microscopes, a scanning electron microscope equipped with a scanning transmission detector and two low-voltage transmission electron microscopes, operated at 25 kV, with the imaging capabilities of a high-voltage transmission electron microscope using different viruses in samples prepared by negative staining and ultrathin sectioning. All of the microscopes provided sufficient optical resolution for a recognition of the viruses tested. In ultrathin sections, ultrastructural details of virus genesis could be revealed. Speed of imaging was fast enough to allow rapid screening of diagnostic samples at a reasonable throughput. In summary, the results suggest that low-voltage microscopes are a suitable alternative to high-voltage transmission electron microscopes for diagnostic electron microscopy of viruses.

The transmission electron microscope (TEM) has had a major impact on materials science in the last five decades, despite the fact that it is necessary to prepare thin samples in order to use the technique. The primary reason for this effectiveness is the ability to access both real space and diffraction data in the same instrument, and to filter in one and observe the effect in the other. This is possible because of the wave nature of electrons and the existence of effective magnetic lenses for focusing. Abbe showed that any lens has the ability to Fourier transform its input wavefield in its focal plane, and to provide a second Fourier transform in the image plane. This is schematically shown in Figure 1. A crystalline object will diffract only in certain directions, with Bragg angles (θB) depending on the inverse of the interplanar spacing. The diffraction pattern is a series of spots in the Fourier, or focal, plane of the lens. A filter placed in the focal plane serves to limit the resolution by limiting the bandwidth of the image, but it also can serve to select certain parts of the Fourier spectrum in the image. The simplest examples of this, as used in optical microscopy, are bright-field and dark-field imaging. In the former the un-scattered beam is allowed to reach the image, in the latter it is not.

AbstractSingle atoms can be considered as the most basic objects for electron microscopy to test the microscope performance and basic concepts for modeling image contrast. In this work high-resolution transmission electron microscopy was applied to image single platinum, molybdenum, and titanium atoms in an aberration-corrected transmission electron microscope. The atoms are deposited on a self-assembled monolayer substrate that induces only negligible contrast. Single-atom contrast simulations were performed on the basis of Weickenmeier-Kohl and Doyle-Turner form factors. Experimental and simulated image intensities are in quantitative agreement on an absolute intensity scale, which is provided by the vacuum image intensity. This demonstrates that direct testing of basic properties such as form factors becomes feasible.

An environmental cell (E-cell) is a gas reaction chamber mounted inside an electron microscope column where thin solid samples can be observed under various gases (O2, H2, N2, NH3 etc.) at selected temperatures. Even though the idea of having an E-cell incorporated in the microscope column is as old as transmission electron microscopy itself, recent developments in the instrumentation and designs of both the microscopes and E-cells have made it possible to obtain high resolution images (0.3-0.6 nm). We have used the differentially pumped model proposed by Swan to modify a PHILLIPS 400T transmission electron microscope for gas-solid studies.Figure la shows a side view cross section schematic of the E-cell fitted in the 9 mm gap between twin lens objective pole pieces. It consists of a small chamber with 200 and 400 μm apertures on sides a and a’ respectively. The walls are machined at the same angle as the pole pieces for an optimum fit to the conical exterior of the pole pieces and the cell is held firmly in place with o-rings (b).

Since publication of the classic text on the electron microscope laboratory by Anderson, the proliferation of microscopes with field emission guns, imaging filters and hardware spherical aberration correctors (giving higher spatial and energy resolution) has resulted in the need to construct special laboratories. As resolutions iinprovel transmission electron microscopes (TEMs) and scanning transmission electron microscopes (STEMs) become more sensitive to ambient conditions. State-of-the-art electron microscopes require state-of-the-art environments, and this means careful design and implementation of microscope sites, from the microscope room to the building that surrounds it. Laboratories have been constructed to house high-sensitive instruments with resolutions ranging down to sub-Angstrom levels; we present the various design philosophies used for some of these laboratories and our experiences with them. Four facilities are described: the National Center for Electron Microscopy OAM Laboratory at LBNL; the FEGTEM Facility at the University of Sheffield; the Center for Integrative Molecular Biosciences at TSRI; and the Advanced Microscopy Laboratory at ORNL.

We developed a 1-MV field-emission transmission electron microscope to help in further improving electron holography, Lorentz microscopy, and high-resolution electron microscopy. This microscope is characterized by an electron beam having the highest brightness ever, 2×1010 A/cm2, and by the highest lattice-resolution below 0.5 Å. These two features were attained by minimizing the mechanical vibration of the whole column and by improving the stability of both the electron beam and the high voltage. If the tiny electron source located at the top of the 7-m-high microscope moves by as little as a fraction of the source size, 50 Å in diameter relative to the column, due to mechanical vibration or beam deflection by the AC magnetic fields, the beam brightness will be greatly degraded. If the ripples ΔE of the high-voltage E exceed ΔE/E = 5 × 10−7 /min, then the inherent monochromatic feature of the beam is deteriorated by the increase in energy spread.Through the preliminary experiments testing the vibration and magnetic shielding of the acceleration tube as well as the high stability of the high voltage, and through the numerical simulations on the vibration modes of the whole column, we were led to the conclusion that the microscope must be separated into three parts that are connected by cables.

The High Voltage Electron Microscopy Laboratory [HVEM] at the University of Wisconsin-Madison, a National Institutes of Health Biomedical Research Technology Resource, has recently been renamed the Integrated Microscopy Resource for Biomedical Research [IMR]. This change is designed to highlight both our increasing abilities to provide sophisticated microscopes for biomedical investigators, and the expansion of our mission beyond furnishing access to a million-volt transmission electron microscope. This abstract will describe the current status of the IMR, some preliminary results, our upcoming plans, and the current procedures for applying for microscope time.The IMR has five principal facilities: 1.High Voltage Electron Microscopy2.Computer-Based Motion Analysis3.Low Voltage High-Resolution Scanning Electron Microscopy4.Tandem Scanning Reflected Light Microscopy5.Computer-Enhanced Video MicroscopyThe IMR houses an AEI-EM7 one million-volt transmission electron microscope.

Thermoelectric device has ability to modify thermal energy into electrical energy or vice versa, and such devices may propose a fabulous possibility in settling of energy problem from an environmental-sustainable aspect. Climate change issue and worldwide shortage of energy is creating exaggerated interests in other new spectacular contrivance of power generation with translucent energy sources. Whenever, the absence of any liquid media or other moving parts, a temperature gradient imposed between the hot and cold junction. A thermoelectric material plays an important role in primary power generation (i.e., combustion, chemical reactions, and nuclear decay), and energy conservation both. Several thermoelectric materials are reported. However, among all of these Tin Telluride (SnTe) displays exclusive features like low-toxicity and eco-friendly behaviour etc. The current prevalence illustrates that at temperature 300 K nano-structuring and band engineering may provide a high thermoelectric performance device of SnTe, which offers a substitute for toxic PbTe in similar operational temperature. The huge area competence and innateness of scaling up with comprehensive constraint of material handling provides possible application of sintering in industrial manufacture of coatings and optoelectronic devices. However, metal chalcogenides of the group IV-VI are gained significant attention due to its fascinating physical properties. These narrow bandgap semiconductors are enormously useful for thermoelectric devices, thermo-voltaic, photovoltaic and as well as various optical applications. Whereas, SnTe semiconductor possesses a cubic rock salt structure with a direct band gap 0.18 eV, which is responsible to make it more attractive. Many more applications such as photo detectors, mid-infrared (3-14 μm) detection and thermoelectric devices of SnTe is a proof of its capacity in material research. A Tin Telluride (SnTe) vacuum evaporated thin films has been synthesized at room temperature (RT) on a glass substrate, which has been proven as a significant enhancement in the figure of merit (ZT) value as p-type material. Moreover, a high-resolution X-ray diffraction (HRXRD) outlines indicated towards a polycrystalline nature in bulk solids as well as in thin films both. Surface morphology of composed grains of variable sizes of these films also investigated using scanning electron microscopy (SEM), which has been further supported by atomic force microscopy (AFM) wherein, the surface parameters (like roughness, skewness, and kurtosis) were measured and analyzed to determine topography of the thin film surface. High-resolution transmission electron microscope (HRTEM) also touches to local microstructural features and crystalline structure, which another level investigation has been confirmed using selected area electron diffraction (SAED) pattern analysis. Four probes method has also been used to determine electrical measurements, which confirm that the thin films behave as a semi-metallic nature. We observed that figure of merit of thin films increases with thickness of the film. The maximum ZT value of ∼ 1.02 for the SnTe thin film with thickness 275 nm and ∼ 1.04 for In-doped SnTe thin film of thickness 450 nm has been observed at room temperature measurement. A detailed analyzes of SnTe is indicated that SnTe is the utmost promising material for thin film photovoltaics, thermoelectric device and IR detector. Whereas, present research work also deals with a comparative study of bulk solids and thin films of SnTe and In-doped SnTe compound semiconducting material. Whereas, it has been observed that optical, electrical and thermoelectric properties of thin films alter with the thickness of thin film. The present thesis has been discussed into seven chapters, which brief discussion has been indicated in the following paragraphs. Chapter 1 introduces to the fundamental aspects of thermoelectric materials. Various kinds of thermoelectric materials such as Metal chalcogenides, Superionic conductors, Metal oxides, Silicon-based materials, PGEC thermoelectric materials categorized as Skutterudites, clathrates, half- Heusler alloys, and SnTe has been discussed in this segment (introduction) of the thesis. Literature review of SnTe compound is discussed thoroughly including the detailed explanation about crystalline structures, phase diagrams and related applications. The effect of doping in pure SnTe has also been discussed in detail with an optimal literature survey. Overall, the semiconducting compound materials discussed in this part. This chapter ends with the motivation for the present work. Finally, the objectives of the thesis based on the review of the literature have been incorporated. Chapter 2 describes a brief description of experimental and characterization techniques used in the present investigation for the synthesis of bare SnTe and Indium doped SnTe bulk and thin films. Whereas, a primarily, vertical directional solidification (VDS) and subsequently thermal evaporation technique have been used for the synthesis of the bulk SnTe, In-doped SnTe and their thin films. This chapter includes the details of sophisticated analytical experimental tools like, XRD/ HRXRD, VP-SEM, EDS, TEM/HRTEM, AFM, FTIR, micro-Raman, PL, UV-NIR, TOF-SIMS, EPR, Four probe method (-T) and Herman method (ZT) measurements for different properties. Bulk SnTe and In-doped SnTe in the form of ingot was prepared by the physical route via VDS technique in a vertical muffle furnace. The thin film deposition has been performed on glass, silicon, and NaCl substrate using the thermal vapor deposition instrument and discussed in detail in this chapter. Chapter 3 provides the detailed investigation of the bulk SnTe ingot. This chapter emphasized that SnTe material was prepared by vertical directional solidification (VDS) technique at high temperature via the physical route. Bulk SnTe pallets were used for the structural characterization (XRD). XRD pattern of bulk SnTe confirms the formation of polycrystalline SnTe as well as its atomic-scale range of structural periodicity. From the XRD analysis it is established that both cubic and orthorhombic phases co-exist in bulk SnTe compound. Rietveld refinement of four-time repeated XRD data indicates all best-fitting parameters for analysis of bulk SnTe. SEM and EDX analyses show the existence of cleavage planes on the morphological surface of the bulk SnTe compound. The results obtained from the EDX revealed that the stoichiometry of Sn and Te is maintained perfectly. The microstructural investigations were achieved by employing HRTEM and SAED, which confirm that inter-planar spacing values correlate with XRD data, and various sizes of grains are present in the material. Some grain boundaries have been occurred, establishing about the formations of imperfections in the material. HRTEM micrographs show the disorder in the grain boundaries of different grains, and hence here in most cases, lattice fringes of different grains were merged with each other. FTIR and Micro - Raman spectra revealed that the SnTe is a suitable compound for IR applications. EPR results revealed that holes are present in an abundant concentration, and voids presence makes the material highly paramagnetic. As SIMS spectra revealed the presence of unreacted Tin, Tellurium, SnTe compound, and impurities in the ingot up to ppm level, therefore this may be an appropriate reason for paramagnetic behavior. The confirmation of the p-type nature of SnTe indicates the presence of holes or vacancies in the material, which is also responsible for paramagnetic resonance. The reaction of very – very few oxygen atoms with the material may also be responsible for free electrons in the material, which seems a strongly correlated with Micro-Raman and FTIR results. Electrical properties confirmed that P-type SnTe is semi-metallic, and resistivity is temperature-dependent. These studies explore the feasibility of employing the material in the industrial production line of infrared detectors. Chapter 4 reports the detailed study of SnTe thin films of different thickness deposited on various substrates. By using thermal evaporation equipment, a series of Tin Telluride (SnTe) thin films of varied thicknesses are deposited onto different substrates at 300 K. The morphology, microstructure, topology, optical, elemental mass isotope spectrum, electrical, and thermoelectric properties of SnTe thin films having thicknesses 33 nm to 275 nm have reported here. High-resolution x-ray diffraction (HRXRD) patterns of SnTe thin films revealed the polycrystalline nature with [200], which orientation possessed a cubic structure. Rietveld refinement of XRD data of these thin films indicates all best-fitting parameters for the analysis of crystalline features. The microstructural and morphological structures of all thin films were examined using HRTEM and SEM-EDS, respectively. The distribution of isotopes of various elements in the thin film along with facet and longitudinal channels was expolred by using depth profile determination through the TOF – SIMS technique. Fourier transform infrared spectroscopy spectra reveal the molecular vibrations, narrow bandgap property of material, and suitability of materials in infrared applications. Longitudinal – optical phonon scattering due to the [222] plane orientation is also observed in the micro-Raman spectra at room temperature, which corresponds to a peak in the range 120–130 Raman shift/cm−1. Hence, the change in optical and microstructural properties at the nano-regime resulted in a shift towards the near-infrared region with an enhancment in the thickness of the thin films. Electrical properties enhance with the decrease of thin-film thickness. Whereas, figure of merit (ZT) equal to 1.02 is the highest value for a thin film of thickness 275 nm among all four thin films. Chapter 5 reports the detailed study of doping of the Indium (In) element in SnTe bulk compound and In-doped SnTe thin films with thickness of 50 nm, 245 nm and 450 nm. Rietveld refinement of XRD data of bulk In0.1Sn0.9Te compound and thin films indicates the formation of polycrystalline bulk and thin films. Rietveld refinement of XRD data indicates all best-fitting parameters for analysis of In-doped SnTe thin films. Morphological, microstructural, topological, optical, and thermoelectric properties have also described in this chapter. SEM, TEM and AFM micrographs revealed that nanoparticles (NPs) of different size from 50 nm to 500 nm have been spread along the whole of surface of thin film. These different size NPs can affect the optical properties of these thin films, because due to absorption of light in visible region the variable size of NPs can emit diverse colors radiations. However, the metallic NPs show dissimilar physical and chemical properties in comparison of bulk metals. It is clear that NPs have large surface area to volume ratio hence in the case of NPs huge interactive interface exist between the adjacent particle and thier local surroundings. As per use of any compound rather in the form of bulk material or in the form of nanomaterials the properties of similar chemical compositional material changed significantly. Thermoelectric properties (figure of merit) revealed that ZT = 1.04 is highest for the film of thickness 450 nm. Chapter 6 describes the detailed study of Ultra-fast spectroscopy for SnTe and In-doped SnTe thin films. This chapter describes relationship about the study of optical properties with dynamics of thin film. Ultrafast laser spectroscopy is a sophisticated technique in which ultrashort pulse lasers generally used to study the dynamics of reaction mechanism up to tremendously small-time scales. Various techniques are practiced for the study of the dynamics of holes and electrons, atoms or molecules. The time domain part of frequency-resolved spectroscopy is the main component of ultrafast molecular spectroscopy. In the case of ultrafast spectroscopy, coherent quantum levels lead to time-dependent dynamics which is belongs to the traditional mechanical movement. In ultrafast spectroscopy, a 70-fs pulse is applied to pump the specimen, which is generated as a result of a mode-locked laser beam, amplifier, and optical parametric amplifier (OPA). The mode-locked laser is of MICRA, which generates a 35-fs pulse of 800 nm with a 320mW average power. The pulsed laser is then amplified using a COHERENT amplifier in which the Ti: Sapphire crystal is used to amplifies the pulse laser to 4 W. This laser pulse is then split into 70:30 using a beam splitter in which 30% of the laser beam is passed through the delay stage to provide a 6 ns long delay. The delayed beam is then passed through the Ti: Sapphire crystal to generate a continuum in the NIR range of 800-1600 nm. Simultaneously, the remaining 70% of the laser beam is passed through TOPAs, which is an OPA. The HELIOS spectrometer is used to detect the differential reflectance in which the InGaAs detector is used. The system is calibrated through the in-house built BND in CSIR-NPL. Chapter 7 provides a summary of the research work done in this thesis. It also suggests and outlines open issues and the future course of research in the area of Chalcogenide materials and compound semiconductors.

Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2018.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 47-50).
III-V materials have great potential for integration into future complementary metal-oxide-semiconductor technology due to their outstanding electron transport properties. InGaAs n-channel metal-oxide-semiconductor field-effect transistors have already demonstrated promising characteristics, and the antimonide material system is emerging as a candidate for p-channel devices. As transistor technology scales down to the sub-10-nm regime, only devices with a 3D configuration can deliver the necessary performance. III-V fin field-effect transistors (finFETs) have displayed impressive characteristics but have shown degradation in performance as the fin width is scaled to the sub-10-nm regime. In this work, we use high-resolution transmission electron microscopy (HRTEM) in an effort to understand how interfacial properties between the channel and high-k dielectric affect device performance. At the interface between the channel material, such as InGaSb or InGaAs, and the high-k gate dielectric, properties of interest include defect density, interdiffusion between the semiconductor and dielectric, and roughness of the dielectric - semiconductor interface. Using HRTEM, we can directly study this interface and try to understand how it is affected by different processing conditions and its correlation with device characteristics. In this thesis, we have analyzed both InGaAs and InGaSb finFETs with state-of-the-art fin widths. Analysis of TEM images was combined with electrical data to correlate interfacial properties with device performance. We compared the materials properties of InGaAs and InGaSb and also explored the impact of processing steps on interfacial properties.
by Lisa Kong.
S.B.

Graphene, a one-atom thick sheet of carbon, is the thinnest, strongest and most electrically conductive material ever discovered. Alongside carbon nanotubes it is part of the group of nanocarbons whose unique properties have sparked huge interest in possible applications, including electronic devices, solar cells and biosensors. Doping of these materials allows for the modification of their optical and electronic properties,which is crucial to realising these applications. Studying the properties of these doped materials at atomic resolution and finding controllable and industrially scalable routes to doping, such as low energy ion implantation, are thus essential if they are to becomethe materials of the future. In this thesis, highly localised optical enhancements in metal doped graphene are studied using energy-filtered transmission electron microscopy in a monochromated and aberration corrected electron microscope. The ideal conditions for imaging the low energy loss region of graphene using EFTEM are discussed and new methods to compensate for image artifacts when using this technique at high resolution are presented. Density functional theory is used to reveal new visible spectrum plasmon excitations in the electron energy loss spectra of boron and nitrogen doped nanocarbons. Atomic resolution scanning transmission electron microscopy and nanoscale electron energy loss spectroscopy are used to investigate controllable and defect-free substitutional doping of suspended graphene films through low energy ion implantation. Computational methods for filtering high angle annular dark field images are shown and software for the automated processing and spectroscopic analysis of these images is developed.

This thesis concerns the application of aberration corrected scanning transmission electron microscopy (STEM) to the quantitative analysis of industrial Pd-Pt core-shell catalyst nanoparticles. High angle annular dark field imaging (HAADF), an incoherent imaging mode, is used to determine particle size distribution and particle morphology of various particle designs with differing amounts of Pt coverage. The limitations to imaging, discrete tomography and spectral analysis imposed by the sample’s sensitivity to the beam are also explored. Since scattered intensity in HAADF is strongly dependent on both thickness and composition, determining the three dimensional structure of a particle and its bimetallic composition in each atomic column requires further analysis. A quantitative method was developed to interpret single images, obtained from commercially available microscopes, by analysis of the cross sections of HAADF scattering from individual atomic columns. This technique uses thorough detector calibrations and full dynamical simulations in order to allow comparison between experimentally measured cross section to simulated ones and is shown to be robust to many experimental parameters. Potential difficulties in its applications are discussed. The cross section approach is tested on model materials before applying it to the identification of column compositions of core-shell nanoparticles. Energy dispersive X-ray analysis is then used to provide compositional sensitivity. The potential sources of error are discussed and steps towards optimisation of experimental parameters presented. Finally, a combination of HAADF cross section analysis and EDX spectrum imaging is used to investigate the core-shell nanoparticles and the results are correlated to findings regarding structure and catalyst activity from other techniques. The results show that analysis by cross section combined with EDX spectrum mapping shows great promise in elucidating the atom-by-atom composition of individual columns in a core-shell nanoparticle. However, there is a clear need for further investigation to solve the thickness / composition dualism.

Abstract The dual-beam system, which combines a high-resolution scanning electron microscope (SEM) with a focused ion beam (FIB), allows sample preparation, imaging, and analysis to be accomplished in a single tool. This paper discusses how scanning transmission electron microscopy (STEM) with the electron beam enhances the analysis capabilities of the dualbeam. In particular, it shows how, using the combination of in-situ sample preparation and integrated SEM-STEM imaging, more failure analysis and characterization problems can be solved in the dual-beam without needing to use the Ångstrom-level capabilities of the transmission electron microscope (TEM).

The high-resolution electron microscope has been used successfully to study the structure and morphology of thin films including interfaces at near-atomic resolution. Recently the technique has been expanded to study the dynamics of thin film transformations and reactions in real time. These techniques possess enormous potential for those who wish to obtain atomic-level information of value in characterizing thin-film deposits and the changes they undergo with a variety of treatments. Four illustrations are given here.

Abstract Recent developments in transmission electron microscopy (TEM) sample preparation have greatly reduced the time and cost for preparing thin samples. In this paper, a method is demonstrated for viewing thin samples in transmission in an unmodified scanning electron microscope (SEM) using an easily constructed sample holder. Although not a substitute for true TEM analysis, this method allows for spatial resolution that is superior to typical SEM imaging and provides image contrast from material structure that is typical of TEM images. Furthermore, the method can produce extremely high resolution x-ray maps that are typically produced only by scanning transmission electron microscope (STEM) systems.

Abstract Currently, the helium ion microscope (HIM) can be operated in three imaging modes; ion induced secondary electron (SE) mode, Rutherford backscatter imaging (RBI) mode, and scanning transmission ion imaging (STIM) mode. This paper will provide an overview of microscope’s ion source, its ion optics, the system architecture, the fundamentals of these three imaging modes and many FA related examples. Recently integrated with the microscope are a Rutherford Backscatter (RBS) detector for materials analysis and a gas injection system (GIS) for material modification. We will describe this new hardware and suggest how these additions could also contribute to the helium ion microscope being an important failure analysis tool.

Abstract This paper describes the problems encountered and solutions found to the practical objective of developing an imaging technique that would produce a more detailed analysis of IC material structures then a scanning electron microscope. To find a solution to this objective the theoretical idea of converting a standard SEM to produce a STEM image was developed. This solution would enable high magnification, material contrasting, detailed cross sectional analysis of integrated circuits with an ordinary SEM. This would provide a practical and cost effective alternative to Transmission Electron Microscopy (TEM), where the higher TEM accelerating voltages would ultimately yield a more detailed cross sectional image. An additional advantage, developed subsequent to STEM imaging was the use of EDX analysis to perform high-resolution element identification of IC cross sections. High-resolution element identification when used in conjunction with high-resolution STEM images provides an analysis technique that exceeds the capabilities of conventional SEM imaging.

Abstract The carbide precipitation of 2.25Cr-1Mo-0.25V steel is studied during the head-fabrication heat treatment process using gold replica technique, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and selected area electron diffraction (SAED). Shapes, structures and sizes of carbides before and after heat treatment are analyzed. The dissolution of strip-shaped carbides and the precipitation of granular carbides are confirmed. Amorphous films at the boundaries of carbides are observed by high-resolution transmission electron microscope (HRTEM), which is formed due to the electron irradiation under TEM.

Abstract Modern electronic systems rely on components with nanometer-scale feature sizes in which failure can be initiated by atomic-scale electronic defects. These defects can precipitate dramatic structural changes at much larger length scales, entirely obscuring the origin of such an event. The transmission electron microscope (TEM) is among the few imaging systems for which atomic-resolution imaging is easily accessible, making it a workhorse tool for performing failure analysis on nanoscale systems. When equipped with spectroscopic attachments TEM excels at determining a sample’s structure and composition, but the physical manifestation of defects can often be extremely subtle compared to their effect on electronic structure. Scanning TEM electron beam-induced current (STEM EBIC) imaging generates contrast directly related to electronic structure as a complement the physical information provided by standard TEM techniques. Recent STEM EBIC advances have enabled access to a variety of new types of electronic and thermal contrast at high resolution, including conductivity mapping. Here we discuss the STEM EBIC conductivity contrast mechanism and demonstrate its ability to map electronic transport in both failed and pristine devices.

Soft x rays are an excellent probe for high spatial resolution detection of low atomic number specimens. We have developed a scanning microscope at the National Synchrotron Light Source (NSLS) which uses a small (~0.2-μm) spot of x rays in the 24-44-Å wavelength range. The microscope can form transmission images in real time at a fixed wavelength, or, by making an image of the difference in transmission on either side of an element's absorption edge, it can make a high resolution map of that element’s concentration. We have used the microscope primarily for imaging and microanalysis of biological specimens. However, with minor modifications the instrument can be used for high resolution material science studies of surfaces or bulk specimens without the requirements of excessive specimen thinning or vacuum compatibility presently required by electron probe instruments. The x-ray probe is presently formed by a Fresnel zone plate fabricated at IBM using electron-beam lithography. We will improve the resolution considerably with higher resolution zone plates fabricated by a variety of techniques. We will also increase the throughput of the instrument several orders of magnitude by moving from a bending magnet source of synchrotron radiation to the soft x-ray undulator soon to be installed on the x-ray storage ring at the NSLS. With these improvements we plan to make high resolution (< 1000-Å) scanned images in <1 min.