bluuebunny/crossref_metadata_2025_split huggingface dataset:
The calculation of backscattered images for cross-section samples in the scanning electron microscope (SEM)
Authors: Ly T.D. , Howitt D.G 
Published: June 2020

The calculation of image contrast in heterogeneous samples can be done using Monte Carlo techniques if the electron trajectories can be calculated through the composition profiles in the specimen. Most of the programs that are available are designed to calculate signal intensities from samples of uniform atomic number and density (e.g Joy 1988, Reimer and Steltzer 1987) but some success has been achieved in the description of samples with distinct composition profiles by extrapolating these results.The image simulations we have done here are based upon Monte Carlo calculations of the electron backscattered signal from samples where the composition variations can be taken into account in determining both the elastic and inelastic scattering cross sections. This work involved extending the program developed by Joy (1988) and comparing the calculated signal intensities to the values derived experimentally from a specimen of well defined geometry. In the program the elastic scattering cross-sections, which describe the collisions of the electrons with the atomic nucleus are described by a Rutherford model given by(1)
A miniature MCP detector for low voltage SEM imaging
Authors: Hooper John , Ellis Glenn , Easterbrook David 
Published: June 2020

MicroChannel plate (MCP) based detectors are becoming widely accepted in SEM imaging applications requiring low beam energies and currents. Images have been obtained of uncoated samples without the usual charging effects and of semiconductor materials with little or no damage to sensitive surfaces. Useful images have been obtained with beam energies as low as 200 v and currents as low as 2 pa.The major limitations of the current generation of MCP detectors for SEM are their size (diameter) and thickness. The diameter of the typical MCP detector exceeds that of the polepiece tip of most SEM instruments, lowering the maximum angle at which samples may be tilted. Many semiconductor inspection procedures require high tilt angles. The thickness of the detector module limits the sample working distance and, therefore, the resolution of the SEM instrument. The major contributor to detector module thickness is the space required by the metal casing which houses the MCP itself.
High-resolution scanning electron microscopy of thin-film magnetic media of magnetic recording disk
Authors: Ogura K. , Nishioka H. , Ikeo N. , Kanazawa T. , Teshima J. 
Published: June 2020

Structural appraisal of thin film magnetic media is very important because their magnetic characters such as magnetic hysteresis and recording behaviors are drastically altered by the grain structure of the film. However, in general, the surface of thin film magnetic media of magnetic recording disk which is process completed is protected by several-nm thick sputtered carbon. Therefore, high-resolution observation of a cross-sectional plane of a disk is strongly required to see the fine structure of the thin film magnetic media. Additionally, observation of the top protection film is also very important in this field.Recently, several different process-completed magnetic disks were examined with a UHR-SEM, the JEOL JSM 890, which consisted of a field emission gun and a high-performance immerse lens. The disks were cut into approximately 10-mm squares, the bottom of these pieces were carved into more than half of the total thickness of the disks, and they were bent. There were many cracks on the bent disks. When these disks were observed with the UHR-SEM, it was very difficult to observe the fine structure of thin film magnetic media which appeared on the cracks, because of a very heavy contamination on the observing area.
The microscopy of electromigration failures
Authors: Lloyd J. R. , Rose J. H. 
Published: June 2020

Electromigration is the major wearout failure mechanism in the metal conductors of integrated circuits. As such, the study of electromigration is very important in the microelectronics industry, and has been the subject of intense study for over 25 years. The basic physics is fairly well understood, although the precise reasons and mechanisms responsible for the failure process are still the subject of some controversy. Several models have been constructed, all of which adequately predict the major experimental observations, but the underlying mechanisms are very different. The curious thing is that microscopy has not yet been able to provide the evidence necessary to differentiate between the major failure mechanisms.Electromigration is the diffusion of metal atoms in a metal conductor under the influence of a high current density where the mass transport is biased in the direction of electron flow, for n type conductors, by the momentum exchange between conducting electrons and the diffusing metal atoms.
Effect of Thermal ramping rate on defect formation in oxygen-implanted silicon-on-insulator material
Authors: Park Ju-Chul , Krause Stephen , El-Ghor Mohammed 
Published: June 2020

Integrated circuits on SIMOX (Separation by IMplantation of OXygen) have higher speed, radiation hardness, and higher temperature capability. Defects in the top Si layer inhibit bipolar applications and may affect CMOS(Complementary Metal-On-Semiconductor) device yield, operation and reliability. As-implanted SIMOX has many types of defects, including short stacking faults(SFs), multiply faulted defects(MFDs), and {113} defects. In annealed SIMOX, new defects form during the ramping cycle. The effect of thermal ramping rate on the development of new defects has received only limited study. In this work, the effects of rapid thermal annealing(RTA) and thermal ramp rate on defect density and structural change were studied.Two set of samples were prepared with different oxygen doses. First, one set of (100) Si wafers was implanted with a high dose of 1.8×l018cm−2 at 200 KeV at 620°C. A rapid thermal anneal(RTA) wafer was obtained from a lamp anneal for 1 minute at 1320°C using a ramp rate of 50°C/sec. A portion of this sample was then conventionally annealed in a tube furnace for 5 hours at 1320°C. Another set of (100) Si wafers was implanted with a low dose of 3×l015cm−2 at 25°C. Different samples were then annealed at 1250°C for 30 sec using three ramp rates of 50°C/sec, l°C/sec and 0.1°C/sec. Cross-sections of the samples were studied with conventional transmission electron microscopy (CTEM) at 200 KeV.
A correlative study of microstructure and surface topography in Al-1.5%Cu films
Authors: Theodore N. David , Cao Bea , Carrejo Juan , Crozier Peter A. 
Published: June 2020

Al(Cu) is currently being used for interconnects in semiconductor integrated-circuits. Problems that arise with use of the material are electromigration, stress-migration, and corrosion. Electromigration and stress-migration behaviors of the films are known to depend on grain-sizes and distributions in the material. Surface topography of the films could possibly affect stress-migration as well as use of the material in multi-level metallization schemes. The present study investigates the extent of correlation between microstructure and surface topography in Al-1.5%Cu films.Substrates used for this study consisted of (100) silicon wafers with a 200 nm silicon-dioxide layer on top. Al(1.5%Cu) was sputtered onto the substrates; substrates were held at a temperature of 450°C during sputtering. Layer thicknesses were ∼740 nm. Scanning electron-microscopy was performed using a Cambridge 250-MK III SEM equipped with a heating stage. Plan-view TEM specimens were prepared in the 100 substrate-geometry. These were then analyzed using bright-field and dark-field TEM imaging techniques. A JEOL JEM 200CX transmission electron microscope was used for the investigation, operating at 200 kV.
The morphologies and electrical properties of indium contacts on (100) cadmium telluride surfaces
Authors: Letsoalo A.M. , Lee M.E. , de Neijs E.O. 
Published: June 2020

Semiconductor devices require metal contacts for efficient collection of electrical charge. The physics of these metal/semiconductor contacts assumes perfect, abrupt and continuous interfaces between the layers. However, in practice these layers are neither continuous nor abrupt due to poor nucleation conditions and the formation of interfacial layers. The effects of layer thickness, deposition rate and substrate stoichiometry have been previously reported. In this work we will compare the effects of a single deposition technique and multiple depositions on the morphology of indium layers grown on (100) CdTe substrates. The electrical characteristics and specific resistivities of the indium contacts were measured, and their relationships with indium layer morphologies were established.Semi-insulating (100) CdTe samples were cut from Bridgman grown single crystal ingots. The surface of the as-cut slices were mechanically polished using 5μm, 3μm, 1μm and 0,25μm diamond abrasive respectively. This was followed by two minutes immersion in a 5% bromine-methanol solution.
EELS detection limits
Authors: Hunt J. A. , Williams D. B. 
Published: June 2020

Why determine detection limits?A natural question to ask about any quantitative technique, including EELS in the STEM, is “How little of <x> can be observed?” Detection limits serve as a guide to what problems are solvable and what are the best techniques to analyze specific systems, e.g., EELS vs. EDXS vs. SIMS, etc. The exercise of determining EELS detection limits provides a sobering reminder of sizable uncertainties of numerous EELS variables, e.g., cross-sections, analyzed volumes, interaction delocalization, etc. Minimizing detection limits require optimization of many issues of the field, such as beam size and energy spread, the spectrometer and detector, quantitation techniques and specimen preparation. Additionally, comparing obtainable detection limits with theoretical values allows assessment of the rate at which a major portion of the field of EELS is maturing. Such assessments provide useful clues to if and where further development work is justified.Traditional detection limit calculations. Typically there have been two types of detection limits discussed in EELS, the minimum detectable mass (MDM) and the minimum mass fraction (MMF).
Analysis of microsamples with an FT-Raman microscope
Authors: Kawai N.T. , Sawatski J. , Lehner C. 
Published: June 2020

Rapid developments in near-IR filter and detector technology have resulted in FT-Raman spectroscopy emerging as a powerful technique in both research and analytical laboratories. The more recent advances in FT-Raman instrumentation now emphasize the optimization of different sampling accessories, including microsampling techniques. Microscopes attached to conventional Raman spectrometers operating at visible wavelengths have already proven to be applicable to many problems of chemical analysis. However, the optimized combination of an optical microscope and a near-IR FT-Raman spectrometer currently enables the analysis of very small samples which would normally fluoresce with visible excitation. Such samples include polymer fibers and thin films, dyes on fabrics, and small biological samples.In FT-Raman microscopy, the microscope is coupled to the near-IR FT-Raman spectrometer via fiber optic cables. These cables transfer the Nd:YAG laser beam from the spectrometer to the microscope, and channel the scattered light back again to be modulated by the interferometer and measured by the high sensitivity near-IR detector.
Quantitative mass analysis of cryosections in the field-emission STEM
Authors: Andrews S.B. , Buchanan R.A. , O'Connell M.F. , Leapman R.D. 
Published: June 2020

Low-dose, dark-field imaging in the field-emission STEM is a well documented method for mass mapping isolated protein molecules and macromolecular assemblies. Now, technical advances can provide truly thin, minimally compressed cryosections of unfixed, direcdy frozen tissues. These sections are thin enough-and have enough ultrastructural detail-to make mass mapping useful for directly and quantitatively measuring the in situ mass of cell constituents without beam-induced mass loss or other damage. In this report, we illustrate how dark-field STEM of cryosections can be used to measure the mass of single organelles in Purkinje cell dendrites, which is of interest because certain of these organelles participate in ion and water flow following synaptic activity-induced calcium mobilization.Cryosections, prepared in a Reichert FC-4E cryoultramicrotome at ca. -160 C, were cut to a nominal thickness of 100 nm on a 35° Diatome diamond knife with the aid of an antistatic device. Sections mounted on carbon/Formvar-coated grids were transferred (frozen-hydrated) into a modified VG HB501 field-emission STEM prior to freeze-drying at ca. -110 C.
Ionic changes in cultured heart cells following calcium depletion and repletion
Authors: Hockett Daniel , Freudenrich Craig C. , Mohr Jennifer R. , Lieberman Melvyn , Ingram Peter , LeFurgey Ann 
Published: June 2020

Intact perfused hearts subjected to calcium depletion and subsequent repletion undergo irreversible structural damage characterized by sarcolemmal disruption, hypercontracture, and the appearance of large electron dense deposits (thought to be calcium phosphate) within mitochondria. This structural damage is accompanied by increased intracellular Na+ and Ca++. Cultured embryonic chick heart cells subjected to the same conditions do not exhibit ultrastructural damage but do undergo similar ionic changes. This study characterizes the intracellular ionic changes associated with calcium repletion and assesses the role of mitochondria in the buffering of calcium.METHODS: Heart cells were obtained from 11-day-old chicken embryos and cultured as spherical aggregates for 3-4 days. The aggregates were then incubated at 37°C in HEPES buffered solution containing 1.3 mM Ca for 10 minutes (control period). Following this control period, the aggregates were incubated for 10 minutes in Ca-free HEPES buffer containing 1mM EGTA (depletion period). Finally, the aggregates were returned to normal, Ca-containing, HEPES buffer (repletion period).
Magnesium and sulfur in mast cell and basophil granules of lower vertebrates in relation with histamine
Authors: Takaya Kenichi 
Published: June 2020

Mast cell and basophil granules of the vertebrate contain heparin or related sulfated proteoglycans. Histamine is also present in mammalian mast cells and basophils. However, no histamine is detected in mast cell granules of the amphibian or fish, while it is shown in those of reptiles and birds A quantitative x-ray microanalysis of mast cell granules of fresh frozen dried ultrathin sections of the tongue of Wistar rats and tree frogs disclosed high concentrations of sulfur in rat mast cell granules and those of sulfur and magnesium in the tree frog granules. Their concentrations in tree frog mast cell granules were closely correlated (r=0.94).Fresh frozen dried ultrathin sections and fresh air-dried prints of the tree frog tongue and spleen and young red-eared turtle (ca. 6 g) spleen and heart blood were examined by a quantitative energy-dispersive x-ray microanalysis (X-650, Kevex-7000) for the element constituents of the granules of mast cells and basophils. The specimens were observed by transmission electron microscopy (TEM) (80-200 kV) and followed by scanning transmission electron microscopy (STEM) under an analytical electron microscope (X-650) at an acceleration voltage of 40 kV and a specimen current of 0.2 nA. A spot analysis was performed in a STEM mode for 100 s at a specimen current of 2 nA on the mast cell and basophil granules and other areas of the cells. Histamine was examined by the o-phthalaldehyde method.
Visibility of two intermixed phases as a function of grain size and signal-to-noise: a computer simulation
Authors: Bright David S. 
Published: June 2020

In electron microscope or microprobe images, noise obscures the visibility of objects. The noise level can be reduced at the cost of increasing the image collection time, beam current, detector efficiency, etc. How good does the signal to noise have to be in order for the operator to be able to visually detect two intermixed phases of material?In our previous papers we related visibility of single, well separated objects to object size and shape and to the Rose parameter, k, which is related to object contrast. In this paper we determine the imaging conditions for being able to detect the presence of two phases versus a uniform phase.In his paper in 1948 on the quality of television transmission of images, Rose defined a parameter, k, which we generalize and relate to the signal quality for objects in digital images. As illustrated in Fig. 1, k = "signal"/"noise", where "signal" indicates the excursion in pixel counts due to the object against the background and "noise" indicates the scatter in pixel counts for either the object or the background.
Standardless quantitative x-ray analysis
Authors: pouchou Jean-Louis , Pichoir Françoise 
Published: June 2020

The ϕ(ρz) models developed during the recent years (Gaussian, PAP, XPP) have been shown by several authors to improve significantly the capability of quantitative x-ray microanalysis, mainly in the field of light elements, tilted specimens, and layered specimens. An increasing number of users is now able to take advantage of these models, since some of them have been implemented in EPMA or EDS commercial softwares.However, most of the reported successful applications are the result of analyses with standards, where the basic data are the relative x-ray intensities (also called k-ratios). Indeed, analyses with standards are well adapted to the electron microprobes, and permit to obtain very accurate results. But in the scanning electron microscopes (SEM), the operations of acquiring, processing and handling the EDS spectra of all the required standards are really time consuming. It is why an EDS standardless mode giving satisfactory quantitative results would be so useful, even for those laboratories which can also operate an electron microprobe for the applications requiring the highest degree of accuracy.
A new and versatile computer program for correcting EPMA data
Authors: Farthing I , Love G , Scott VD , Walker CT 
Published: June 2020

A new computer program has been developed to convert electron probe microanalysis data into accurate measurements of chemical composition. It is menu-based and designed to operate off-line using any IBM PC compatible computer. As shown in the flowchart, fig. 1, the architecture is modular and the programming language adopted is a compilable version of BASIC which possesses much of the processing speed associated with FORTRAN or C. Specimens containing up to fifteen elements, with 4 ≤ Z ≤ 96, can be handled and all the major x-ray lines (Kα, Kβ, Lα, L(β, Mα and Mβ) are available for analysis purposes.The procedure itself is based upon the classical ZAF approach in which corrections for atomic number (Z), x-ray absorption (A), characteristic fluorescence (Fl) and continuum fluorescence (F2) are treated independently. The factors dealing with fluorescence are essentially those of Reed (characteristic) and Springer (continuum) although both contain minor updates. However, the atomic number and absorption factors are the authors' own and the latter, developed from a quadrilateral representation of the x-ray distribution with depth in a solid, distinguishes this program from others.
The Use of Monte Carlo Simulations in Quantitative Electron-Probe Microanalysis
Authors: Karduck Peter , Ammann Norbert 
Published: June 2020

The interaction of a focused beam of monochromatic electrons with a solid sample is a complex many-particle problem, which cannot be fully described by analytical methods. But already in the early sixties trajectories of single electrons were simulated numerically on computers (1,2,3). This method was called Monte Carlo simulation (MC). Sequential simulation of some thousand trajectories accumulates a set of data, sufficient to provide information about
-fraction of backscattered electrons,-fraction of transmitted electrons in case of thin film samples,-ionization probability for certain electron shells as a function of sample depth,-calculation of x-ray intensities generated in or emitted from the sample,-energy distribution of backscattered electrons or of electrons in certain depth,-calculation of signal generation in samples with complex geometries.
For all these applications the physical processes of electron - solid interaction needed to be described as realistic and accurate as possible, which was always - and is still - in contradiction to the limitations of existing theories, their applicability in such a complex problem, and of course to the limitations of computer capacities.
Quantitative digital x-ray imaging of the outer shell layer of mytilus edulis (Bivalvia)
Authors: Parker Donald L. , Rosenberg Gary D. 
Published: June 2020

Compositional mapping using digital x-ray imaging has been applied to a variety of applications. The extension of these procedures permitting complete quantitation allows EPM application where detailed structures exist requiring higher resolution. We apply these techniques here for the first time to the study of the molluscan shell. The outer shell layer of the mussel, Mytilus edulis, consists of fibrous calcific prisms (1-3μm diameter) which are organized structurally as layers corresponding to growth increments (up to ca.100μm thick, deposited daily, normal to the direction of growth). Digital imaging is used here to precisely determine the composition of these layers with high spatial resolution.Digital images were obtained with a Cameca® three spectrometer EPM system interfaced to a Kevex 8000® analyzer/imaging system. Images are stored as WDS intensity pixels, with final extraction of image data for complete quantitation being performed offline. The extracted intensities were corrected for dead time, background and transformed into K-ratios for full matrix correction using the CITZAF routines.Shells were sectioned along selected growth axes and polished using alumina followed by ultrasonic cleaning. All specimens were coated with ∼50nm of aluminum (as opposed to carbon) to retard degradation of the carbonate during analysis.
Electron-Microbeam investigation of late quaternary sand sediments from the lagoon of venice (Italy)
Authors: Bonardi Maurizio 
Published: June 2020

Electron probe microanalysis (EPMA) has been used to investigate the mineral assemblage of sand samples from the Venice Lagoon Quaternary sediments. These sediments consist mainly of sand, silt and clay layers with some peat lenses. The boundary between the Holocene and Late-Pleistocene is marked by an overconsolidated layer of clay, related to the origin of the Venetian Lagoon. Because in some area of the basin this clay layer has been eroded away it is not always possible to accurately define the limit between the Holocene and Pleistocene sedimentations.Seventeen continuous cores collected for geotechnical purposes along the offshore sandy bar that separates the Lagoon of Venice from the open Adriatic Sea, were available for this investigation. The cores 25 to 30 m long included the Holocene and Late-Pleistocene sediments. For this preliminary study about 130 sand samples were selected at different depth in order to characterize the various levels of the sediments, recognize and define possible correlations between the layers in the 17 cores and, most important, define the boundary between the Holocene and Pleistocene sediments.