bluuebunny/crossref_metadata_2025_split huggingface dataset:
In situ Electron Microscopy and its applications to semiconductor reactions at high-resolution
Authors: Sinclair Robert 
Published: June 2020

In situ electron microscopy experiments can provide the most revealing insights into material behavior. However, in order to take full advantage of the observations, quantitative measurements are required so that the underlying mechanisms are completely interpreted. This approach also ensures that specimen and environmental artifacts do not play a role and that real “bulk” processes are being studied. These points are illustrated in this paper by reference to work on reactions in semiconductor systems, especially at high resolution.The technique and practice of in situ microscopy are quite exacting. Thus it is often necessary to record changes in the same specimen area for extensive periods of time (e.g., hours), under identical imaging conditions. One can never be sure when a significant event will take place, or sometimes whether it has actually occurred -- accordingly a high degree of acuity on behalf of the observer is essential. A number of procedures is recommended to check that the results are representative and reproducible, including comparing the structural evolution with that from ex situ samples both qualitatively and quantitatively (e.g., [1]). Some contemporary applications are given in a recent publication.
Combined x-ray, EELS, microanalysis, and electron holography of electrically active electroceramic interfaces
Authors: Ravikumar V. , Wilcox N. , Rodrigues R. P. , Dravid Vinayak P. 
Published: June 2020

A large number of electroceramics derive their useful properties from the presence of electrically active interfaces. Varistors and GB capacitors are examples of important electroceramics where the electrical activity of grain boundary (GB) region controls the macroscopic response of the bulk devices. Electrical activity of GBs is often induced by doping and thermal processing. As a part of a broad program, we are investigating the inter-relationship among GB variables (structure, chemistry, and electronic structure) and GB induced properties in model electroceramics such as SrTiO3.GB doping of SrTiO3 polycrystals was achieved by infiltrating Mn into the GBs under appropriate thermal processing cycle. A quick survey of the microstructure by SIMS revealed that virtually all GBs are decorated with Mn. Subsequently, thin foils were examined for AEM analysis using Hitachi HF-2000 cold field emission gun TEM (FEG TEM), equipped with an Oxford Pentafet x-ray detector and a Gatan 666 PEELS system. A probe size of ~ 1 nm was utilized for microanalysis.
Interfacial composition analysis of silicon nitride whisker reinforced oxynitride glass systems
Authors: Sun E. Y. , Alexander K. B. , Becher P. F. , Hwang S. L. 
Published: June 2020

Microstructural and compositional analysis in many structural ceramics requires sophisticated analytical electron microscopy because of the light elements (O, N, C and B) present in the materials and the nano-scale amorphous phases at the grain boundaries. In the present study, scanning transmission electron microscopy (STEM) combined with energy-dispersive x-ray spectroscopy (EDS) and parallel-detection electron energy-loss spectroscopy (PEELS) was used to analyze the composition at interfaces in β-Si3N4 whisker reinforced oxynitride glass systems. Composition profiles were acquired by either manually stepping the probe across the interface or by sequential integration during slow-rate line-scanning with a < 2.0 nm probe in the STEM mode of a Philips EM400T/FEG microscope.Silicon nitride, which has been recognized as one of the most promising candidates for high temperature applications, is typically densified by employing various sintering aids such as yttria and alumina. Reaction of the sintering aids and the oxide surface layer on Si3N4 particles forms secondary intergranular phases that are primarily silicon metal oxynitride glasses.
AFM study of the dynamics of α-alumina surface faceting during high-temperature processing
Authors: Bench Michael W. , Heffelfinger Jason R. , Barry Carter C. 
Published: June 2020

To gain a better understanding of the surface faceting that occurs in α-alumina during high temperature processing, atomic force microscopy (AFM) studies have been performed to follow the formation and evolution of the facets. AFM was chosen because it allows for analysis of topographical details down to the atomic level with minimal sample preparation. This is in contrast to SEM analysis, which typically requires the application of conductive coatings that can alter the surface between subsequent heat treatments. Similar experiments have been performed in the TEM; however, due to thin foil and hole edge effects the results may not be representative of the behavior of bulk surfaces.The AFM studies were performed on a Digital Instruments Nanoscope III using microfabricated Si3N4 cantilevers. All images were recorded in air with a nominal applied force of 10-15 nN. The alumina samples were prepared from pre-polished single crystals with (0001), , and nominal surface orientations.
Nucleation of pyroxene and amphibole in glassy veins along interfaces and cracks in ultramafic inclusions from San Carlos, Arizona
Authors: Wirth R. 
Published: June 2020

Ultramafic inclusions occur in ellipsoidal bombs in basalt flows. The inclusions of the San Carlos ultramafic inclusion locality have been described in detail by Frey & Prinz (1978). They mainly consist of olivine, orthopyroxene (opx), clinopyroxene (cpx) and Cr-spinel. Ultramafic inclusions are important because they are samples of the upper mantle material, and thus they provide direct insight into the upper mantle processes and composition. Glassy veins are fairly abundant along mineral interfaces and cracks. The glass apparently results from incongruent melting of hydrous phases. The glassy veins are between a few nanometer and several microns wide. Veins with a width > 1 μm exhibit crystals of olivine, pyroxene and feldspar. The narrow veins (< 1 μm) only occasionally show crystallization of small crystals (several hundred nanometer). The early stages of crystallization of pyroxene and amphibole and the chemical composition have been investigated by HRTEM and analytical TEM.Glassy veins along interfaces: small grains (several hundred nanometer) of opx have nucleated at an opx/glass interface.
A microscopist's view of catalysis
Authors: Targos W. 
Published: June 2020

Analytical electron microscopy, AEM, has provided valuable information on the structure, composition, location and size of metal clusters and/or crystallites supported on amorphous or crystalline metal oxide materials. Although this information is vital to the understanding of how a catalyst functions, the catalytic reaction is usually more complex. Many variables must be taken into account to evaluate properly a catalyst. Improper selection of process variables can make a good catalyst perform poorly. Consequently, focusing on specific metal site properties may not always be the appropriate direction to take when evaluating a supported metals catalyst problem.To help the microscopist appreciate the complexity of the problem, the following examples were chosen to illustrate this point. Reforming catalysis involves a complex set of reactions to convert naphtha feed to high octane gasoline. The catalyst is comprised of highly dispersed Pt on a high surface area alumina with Cl. The catalyst is dual functional requiring both metal site activity for dehydrogenation and acidity for isomerization and cyclization.
Studies of surface and structural heterogeneity of carbon supports and carbon-supported catalysts
Authors: Liu J. , Colburn S. M. , Ornberg R. L. , Ebner J. R. 
Published: June 2020

Activated carbons are generally used as support materials for precious metal catalysts. Properties of carbon that are important to catalyst preparation and application include composition, surface area, microstructure and pore shape and size distribution. Macropores (> 50 nm), mesopores (2-50 nm) and micropores (<2 nm) generally coexist in activated carbons. The accessibility of metal particles dispersed in microporous systems is of predominant importance, especially for large molecules that exhibit slow diffusion transport in narrow pores. It is desirable to have metal particles highly dispersed in readily accessible locations. As part of an on-going program of the characterization of carbonsupported catalysts we report some preliminary observations of the microstructure of carbon supports by a variety of electron microscopy techniquesCommercial carbon supports and carbon-supported Pt catalysts were used in this study. High resolution secondary electron (SE) microscopy, low voltage backscattered electron (LVBE) microscopy and high-angle annular dark-field (HAADF) microscopy techniques were employed to extract surface and structural information.
Microstructure of thin film La0.5Sr0.5CoO3 electrode for microelectronics applications
Authors: Wang Z. L. , Zhang Jiming 
Published: June 2020

Increasing circuit densities in dynamic random access memories (DRAMs) is one of the major interests in microelectronics research. In a ferroelectric capacitor memory, conducting electrodes must make intimate and ohmic contact to both sides of the ferroelectric thin film. The bottom electrode serves as the substrate during growth and the top electrode is deposited on top of the ferroelectric film. Single crystalline La0.5Sr0.5CoO3 (LSCO) thin films, which are conductive and low electrical resistivity, have recently grown on both sides of Pb-Zr-Ti-O (PZT) ferroelectric film, which has shown a great potential for making fatigue-free small thickness storage capacitors. The present paper reports the microstructure studies of the LSCO thin films grown on MgO(00l) and LaAlO3(100) (LAO) substrates by the metalorganic chemical vapor deposition (MOCVD) technique.Cross-section specimens were made to examine the structure of the film and its relationship with the substrate. Select-area electron diffraction (SAD) and high-resolution lattice image show that the LSCO film has an epitaxial relationship with the MgO/LAO substrate.
TEM study of phosphorus-implanted pseudomorphic Si0.88Ge0.12 on Si(100)
Authors: David Theodore N. , Lie Donald Y.C , Song J. H. , Crozier Peter 
Published: June 2020

SiGe is being extensively investigated for use in heterojunction bipolar-transistors (HBT) and high-speed integrated circuits. The material offers adjustable bandgaps, improved carrier mobilities over Si homostructures, and compatibility with Si-based integrated-circuit manufacturing. SiGe HBT performance can be improved by increasing the base-doping or by widening the base link-region by ion implantation. A problem that arises however is that implantation can enhance strain-relaxation of SiGe/Si.Furthermore, once misfit or threading dislocations result, the defects can give rise to recombination-generation in depletion regions of semiconductor devices. It is of relevance therefore to study the damage and anneal behavior of implanted SiGe layers. The present study investigates the microstructural behavior of phosphorus implanted pseudomorphic metastable Si0.88Ge0.12 films on silicon, exposed to various anneals.Metastable pseudomorphic Si0.88Ge0.12 films were grown ~265 nm thick on a silicon wafer by molecular-beam epitaxy. Pieces of this wafer were then implanted at room temperature with 100 keV phosphorus ions to a dose of 1.5×1015 cm-2.
Absorption and scattering of ultraviolet radiation by titania pigment in bis-phenol-A polycarbonate
Authors: Hutchins Gudrun A. , Pickett James E. 
Published: June 2020

The surface of bis-phenol-A polycarbonate oxidizes after prolonged exposure to sunlight. During the laboratory testing of stabilizers and coatings, the effect of sunlight is typically simulated by a xenon arc lamp, with maximum polycarbonate sensitivity between 300 and 340 nm. Titania pigment is a strong absorber of ultraviolet radiation and in its presence the affected surface layer will be thinner. The titania pigment utilized in polymer blends typically ranges from 100 nm to 350 nm in diameter.Microtomed polycarbonate thin sections stain very well with ruthenium tetroxide vapor and the degree of staining is a sensitive indicator of the degree of oxidation or chemical reaction. Ruthenium tetroxide oxidizes the polymer surfaces of the thin section which results in the localized precipitation of ruthenium dioxide. In addition, the heavily oxidized surface polymer does not microtome evenly, resulting in a very fine craze pattern that is accentuated by the RuO4 stain.With these techniques it was possible to demonstrate the absorption of ultraviolet radiation by titania particles by imaging the abrupt end of the heavily oxidized layer at the positions of individual pigment particles.
Microstructure of laser-irradiated, conducting Kapton polyimide
Authors: Callahan D. L. , Ball Z. , Phillips H. M. , Sauerbrey R. 
Published: June 2020

Ultraviolet laser-irradiation can be used to induce an insulator-to-conductor phase transition on the surface of Kapton polyimide. Such structures have potential applications as resistors or conductors for VLSI applications as well as general utility electrodes. Although the percolative nature of the phase transformation has been well-established, there has been little definitive work on the mechanism or extent of transformation. In particular, there has been considerable debate about whether or not the transition is primarily photothermal in nature, as we propose, or photochemical. In this study, cross-sectional optical microscopy and transmission electron microscopy are utilized to characterize the nature of microstructural changes associated with the laser-induced pyrolysis of polyimide.Laser-modified polyimide samples initially 12 μm thick were prepared in cross-section by standard ultramicrotomy. Resulting contraction in parallel to the film surface has led to distortions in apparent magnification. The scale bars shown are calibrated for the direction normal to the film surface only.
Preparation of cross section samples of ferrimagnetic iron garnet thin films for EM structural characterization
Authors: Simion B.M. , Ramesh R. , Thomas G. 
Published: June 2020

Ferrimagnetic iron garnet thin film multilayered heterostructures were deposited by pulsed laser deposition on paramagnetic [111]-oriented single crystalline GdGa-garnet (GGG) substrates. Bismuth and rare-earth substituted iron garnet thin films are being presently considered as good potential candidates for the next generation of thermo-magneto-optical (TMO) permanent memories, due to their improved magneto-optical (MO) response to the green laser radiation. As reported previously, improved magnetic and MO properties were shown by multilayered Y3Fe5O12/Bi3Fe5O12 (YIG/BIG) and Y3Fe5O12/Eu1Bi2Fe5Ol2 (YIG/EBIG) heterostructures when compared to their single layer counterparts. The present study tries to elucidate the relationship between the films microstructure and their improved properties. Along with x-ray structural characterization, scanning electron microscopy for topographical characterization and analytical transmission electron microscopy for chemical and microstructural analysis are being used.Due to the brittleness of both films and substrates, conventional cross section sample preparation becomes extremely difficult. Samples under roughly 20 μm thickness break under the lowest load of the dimpler.
Advanced TEM sample preparation techniques for submicron Si devices
Authors: Basham P. B. , Tsai H. L. 
Published: June 2020

The use of transmission electron microscopy (TEM) to support process development of advanced microelectronic devices is often challenged by a large amount of samples submitted from wafer fabrication areas and specific-spot analysis. Improving the TEM sample preparation techniques for a fast turnaround time is critical in order to provide a timely support for customers and improve the utilization of TEM. For the specific-area sample preparation, a technique which can be easily prepared with the least amount of effort is preferred. For these reasons, we have developed several techniques which have greatly facilitated the TEM sample preparation.For specific-area analysis, the use of a copper grid with a small hole is found to be very useful. With this small-hole grid technique, TEM sample preparation can be proceeded by well-established conventional methods. The sample is first polished to the area of interest, which is then carefully positioned inside the hole. This polished side is placed against the grid by epoxy Fig. 1 is an optical image of a TEM cross-section after dimpling to light transmission.
Hydrogen-induced phase transformations in α2+B2 Ti-25Al-10Nb-3V-lMo titanium aluminide
Authors: Pierron X. , De Graef M. , Pollock T.M. , Thompson A.W. 
Published: June 2020

Titanium aluminide alloys containing the DO19α2 (Ti3Al) phase, such as Ti-25Al-10Nb-3V-1Mo (at.%), are known to be sensitive to hydrogen. Such alloys could provide an alternative for conventional Ti alloys in a hydrogen-rich environment, and an understanding of the hydrogen embrittlement mechanisms acting in these materials is needed. Hydrides are known to form in conventional Ti alloys. Hence, a systematic study was undertaken to investigate the possibility of hydrogen-induced second phases in the Ti-25Al-10Nb-3V-1Mo alloy. We report here that internal hydrogen results in the precipitation of an orthorhombic OH phase in the α2 grains. The morphology and the orientations of the orthorhombic variants can be successfully described using group theory and the phenomenological theory of martensitic transformations.The as-received material consisted of bars extruded in the (α2 + β) phase field at 1037°C, then oil quenched. A solutionizing treatment at 1085°C, followed by free cooling at 0.1°C/s to room temperature resulted in a microstructure containing primary α2 grains and α2 secondary laths in a B2 matrix.
Structural determination of L-phase with Aucu(I) ordered structure observed in a new maraging steel
Authors: Liu Ping 
Published: June 2020

A new maraging stainless steel has recently been developed at Sandvik and is termed Sandvik 1RK91 (12Cr-9Ni-4Mo-2Cu-1Ti-0.3Al-0.2Si (wt%)). The anomalous tempering response after aging at 475°C, combined with high strength, ductility, corrosion resistance and a high resistance to overaging were attributed to the formation of a quasicrystalline phase. In addition to this an ordered phase designated L-phase precipitated during prolonged aging. The structure type of this phase was determined by electron diffraction combined with EDX analysis. The material was annealed in the temperature range 1050-1150°C with subsequent air cooling and then aged at 475°C for up to 100 hours. Thin foils and carbon replica were studied using a Jeol 2000 FX analytical transmission electron microscope (TEM/STEM) equipped with a Link AN 10000 EDX system operating at 200 kV.The plate-like L-phase precipitated after prolonged aging at 475°C(100 h) as shown in Fig. 1(a). A typical EDX spectrum from L-phase is shown in Fig. 1(b).
Position-tagged spectrometry: a new approach for EDS spectrum imaging
Authors: Mott Richard B. , Waldman Charles G. , Batcheler Rosa , Friel John J. 
Published: June 2020

Graphical display of the spatial distribution of elements in a specimen has been recognized as a powerful technique since the earliest days of electron-beam x-ray microanalysis. With recent advances in computing power and mass storage, it has become practical to save complete spectra at each pixel rather than simple window counts, providing great flexibility for analytical post-processing. The term "spectrum imaging" has been coined to describe such a data structure.Hunt and Williams give a concise summary of the advantages of spectrum imaging, including the ability to map an element which was not known to be present when the data were acquired, and the ability to integrate spectra from image regions of arbitrary shape to improve statistical precision. Quantitative analysis may also be applied at each pixel to produce a concentration map, which is more informative than the raw or perhaps background-subtracted window counts usually displayed. Sensitive discrimination of phases is possible using various fitting techniques on the pixel spectra, matching them against each other or against standards.
Indirect measurements in micro-space with the EM
Authors: Newberry Sterling P. 
Published: June 2020

At the 1958 meeting of our society, then known as EMSA, the author introduced the concept of microspace and suggested its use to provide adequate information storage space and the use of electron microscope techniques to provide storage and retrieval access. At this current meeting of MSA, he wishes to suggest an additional use of the power of the electron microscope.The author has been contemplating this new use for some time and would have suggested it in the EMSA fiftieth year commemorative volume, but for page limitations. There is compelling reason to put forth this suggestion today because problems have arisen in the “Standard Model” of particle physics and funds are being greatly reduced just as we need higher energy machines to resolve these problems. Therefore, any techniques which complement or augment what we can accomplish during this austerity period with the machines at hand is worth exploring.
Automated measurement of size and visibility of small inclusions in HREM images
Authors: Paciornik S. , Xiao S.Q. , Hinderberger S. , Johnson E. , Dahmen U. 
Published: June 2020

This work describes an automatic image analysis method for measuring the visibility and apparent size of inclusions in a matrix, imaged by HREM. The method is based on intensity changes between the matrix and inclusion regions of the image. It provides a quantitative way of describing changes that are generally interpreted only in a qualitative sense. It also allows for measurements in situations of very low visibility where visual estimates are nearly impossible. The method measures the mean squared intensity difference between lines of an image defined asR = mean [(Im(x) - Im(x0))2]Im(x) is a line, selected by the user, which is scanned across the image. Im(x0) is the first line of the scan, taken in a region away from the inclusion. For each position of Im(x), Im(x0) is subtracted pixel by pixel, and the average of all squared intensity differences, is obtained (R).As the line is scanned across the image, R will oscillate with a period given by the lattice spacing along the scan direction.
Algorithms for automated montage synthesis of images from laser-scanning confocal microscopes
Authors: Becker D. E. 
Published: June 2020

An efficient, robust, and widely-applicable technique is presented for computational synthesis of high-resolution, wide-area images of a specimen from a series of overlapping partial views. This technique can also be used to combine the results of various forms of image analysis, such as segmentation, automated cell counting, deblurring, and neuron tracing, to generate representations that are equivalent to processing the large wide-area image, rather than the individual partial views. This can be a first step towards quantitation of the higher-level tissue architecture. The computational approach overcomes mechanical limitations, such as hysterisis and backlash, of microscope stages. It also automates a procedure that is currently done manually. One application is the high-resolution visualization and/or quantitation of large batches of specimens that are much wider than the field of view of the microscope.The automated montage synthesis begins by computing a concise set of landmark points for each partial view. The type of landmarks used can vary greatly depending on the images of interest. In many cases, image analysis performed on each data set can provide useful landmarks. Even when no such “natural” landmarks are available, image processing can often provide useful landmarks.