bluuebunny/crossref_metadata_2025_split huggingface dataset:
Monte Carlo simulation of CL and EBIC contrasts for isolated dislocations
Authors: Czyżewski Z. , Joy D. C. 
Published: August 2011

AbstractElectron beam‐induced current (EBIC) and cathodoluminescence (CL) are widely used to investigate semiconductor materials and devices, particularly to obtain information on the recombination properties and the geometry of defects. This report describes a simple formulation of CL and EBIC contrasts based on the Born approximation of excess carrier density in the presence of a pointlike defect. Quantitative interpretation of the CL and EBIC images is often difficult because of a lack of accurate theory treating simultaneously both the details of the electron beam penetration in the semiconductor and the generation of EBIC and CL signals. To overcome this difficulty, the Monte Carlo approach to the phenomenon of the electron beam penetration in solids has been developed to calculate the CL and EBIC signals during a simulation of the electron trajectory. Results for an inclined dislocation in GaAs are presented.
Calculation and comparison of the surface ionization ϕ(0)
Authors: August H‐J. , Wernisch J. 
Published: August 2011

AbstractAn analytical expression for the surface ionization ϕ(O) is derived from fundamentals, viz., the ionization cross section and the angular and energy distribution of backscattered electrons. In order to avoid numerical integrations, a simple formula for the energy distribution of backscattered electrons is presented. The values given by the resulting expression for ϕ(O) are compared with those given by already known formulae and with experimental findings. In general, the agreement is quite satisfactory, although the calculated values generally are smaller than those experimentally found, especially at high overvoltages. This can at least partly be explained by secondary fluorescence excited by the continuous radiation, of which the correction has not been taken into account in the experimental determination of the ϕ(O) values.
Design and construction of an environmental SEM (part 4)
Authors: Danilatos G. D. 
Published: August 2011

AbstractA new detection configuration using the gaseous detector device in the environmental scanning electron microscope (ESEM) is demonstrated. First, the pressure‐limiting aperture (PLA1) is used simultaneously as a biased electrode to collect the ionization current produced in the gaseous environment of the microscope. Second, a wire electrode is placed above the pressure‐limiting aperture, and it is shown that enough signal from the specimen escapes through the aperture to produce satisfactory images. These detection configurations allow the use of high specimen chamber pressures.
Atomic scale morphology of the surface of the crystalline Si formed by ion etching
Authors: Song M. , Hashimoto H. , Yokota Y. , Awaji M. 
Published: August 2011

AbstractThe atomic scale structure of the ion‐etched Si surface parallel to (111) and (100) was investigated by transmission electron microscopy (TEM). The cross‐sectional high‐resolution TEM observation of the etched surfaces revealed that the 100 surface consists of small protuberances surrounded by (111) planes smaller than 10 nm, and the 111 surface consists of atomically flat surfaces accompanying small fragments with atomic chain structure both on the surface and in the amorphous layer covering the etched surface.
Size effects in glass fragment identification by micro‐x‐ray fluorescence analysis
Authors: Pozsgai I. , Barna A. , Toth P. 
Published: August 2011

AbstractEnergy‐dispersive x‐ray fluorescence (EDXRF) analysis with a lateral resolution of 300 μm has been used in scanning electron microscopy to carry out model experiments for the identification of small glass fragments. Small sample dimensions can produce size effects which cause intensity changes in the EDXRF spectra as compared with bulk specimen spectra. These effects can be analysed by means of the inelastically scattered Mo Kα source line as long as the x‐ray spot size is smaller than the specimen dimension.
Surface investigations with a combined scanning electron–scanning tunneling microscope
Authors: Fuchs H. , Laschinski R. 
Published: August 2011

AbstractWe have combined a scanning tunneling microscope (STM) with a scanning electron microscope (SEM) for surface investigations of atomically flat surfaces, ultrathin adsorbate films, and material surfaces. The mechanical stability of the hybrid instrument allows high‐resolution SEM of samples mounted on the STM stage and atomic resolution with the STM. Experimental results of combined SEM/STM investigations on textured material surfaces, submicron structures, and atomically flat conducting surfaces are presented. An example is given for surface machining with the STM under SEM control.
Calibration of SEM voltage using electron channeling patterns of silicon
Authors: Kozubowski J. A. , Keller R. , Gerberich W. W. 
Published: August 2011

AbstractThe actual accelerating voltage in a scanning electron microscope (SEM) was determined using electron channeling patterns (ECPs). The technique involves selection of a set of high index lines. The properly chosen set of lines exhibits highly sensitive shifts as voltage is changed, allowing rapid SEM voltage calibration. The actual voltage is determined from a simple formula involving measurement of two distances on an ECP obtained from (100) silicon. Such calibrations were performed using both (100)Si and (100)GaAs crystals and the results were compared with voltage estimates from the high energy end of the continuous x‐ray spectrum from silicon. The ECP determination was accurate to about 0.1 keV for a nominal setting of 15 keV. This is comparable to the accuracy of the x‐ray technique when short (∼300 s) counting times are used.
Mapping mineralogy distribution and abundance in rock samples by scanning Fourier transform infrared microscopy
Authors: Liang K. K. , Supp M. , Murphy W. F. 
Published: August 2011

AbstractScanning Fourier transform infrared microscopy (SFTIRM) provides a nondestructive, automated technique that gives both spatial and quantitative description of mineralogy in rocks on a microscopic scale. SFTIRM is essentially a combination of Fourier transform infrared spectroscopy and scanning microscopy. This report describes and demonstrates the principle and operation of the technique. Mineral identification is based on specular reflectance spectra collected in the midinfrared. Mineral abundances are extracted by two different spectral fitting algorithms: least‐mean‐squares (LMS) and linear area fitting (LAF). A sedimentary rock composed mostly of dolomite, some quartz, and finely layered illite is imaged. The SFTIRM images clearly show the spatial distribution and abundance variations of the minerals.
The prospects of a universal correction procedure for quantitative EPMA
Authors: Scott V. D. , Love G. 
Published: August 2011

AbstractAn overview is given of correction methods for quantitative electron probe microanalysis (EPMA). First, the physical basis of the technique is described; this includes a short treatment of earlier proposals to solve the problem. After pointing out the limitations of these methods, attention is focused on the more recent “curve‐fitting” approaches to derive correction formulae. It is concluded that several such methods are available which give very good results and that the original objective of producing a universal correction procedure for EPMA is now within grasp.
Energy‐dispersive x‐ray microprobe analysis of materials containing light elements using peak ratios
Authors: Hemens C. M. , Haythornthwaite R. F. , Nandi B. N. 
Published: August 2011

AbstractQuantitative analyses of light elements using energy‐dispersive x‐ray microanalysis (EDX) is increasingly possible since the development of sealed light element ultra‐thin window detectors. However, the computer programs available for quantitative analyses fail for light elements because the correction and background modelling parameters are not accurately known. Therefore, we have developed a simple method of light element quantitative analysis using the peak ratios of two elements as the basis for calibration curves using stable standards. The use of peak ratios avoids the need for accurate ZAF corrections and minimizes many experimental variables. This article describes the criteria for the selection of standards, and the development of the calibration curve in the case of compounds containing oxygen and carbon. The success of the method depends on careful sample preparation and predetermined experimental parameters. The method has been successfully applied to the surface analysis of fresh and oxidized Western and Eastern Canadian coals.
Confocal laser‐scanned microscopy: Analog signal processing
Authors: Szarowski D. H. , Barnard D. P. , Smith K. L. , Swann J. W. , Holmes K. V. , Turner J. N. 
Published: August 2011

AbstractBiological samples labelled with fluorescent markers often result in specimens with a dynamic range that is less than ideal for imaging with the confocal laser‐scanned microscope. This range can be either too great or too small, and thus prevents the entire image from being processed and/or displayed at the same time. The effect of analog signal processing to overcome this limitation was tested using a modified GW Electronics Image Enhancer in the image pipeline of a Bio‐Rad MRC‐500 Confocal Laser Scanning Microscope. The analog preprocessing did not interfere with subsequent digital processing. The use of homomorphic filtering allowed the dynamic range to be compressed. Fine structures with low signal levels were imaged with improved contrast while structures with high signal levels, did not saturate the detection and display systems. When the black levels were properly manipulated, the processor could be used to enhance signals that were near the noise level, in effect expanding the dynamic range. Both applications resulted in improved image quality and signal to noise. Other analog functions, notably logarithmic and exponentiation were also evaluated. Analog preprocessing produces images with better signal to noise than standard images after contrast stretching and background subtraction by off‐line digital processing. Since the analog processor functions in real time, image collection could be optimized directly, and subsequent digital processing further improved the images.
Imaging of intramembranous particles in frozen‐hydrated cells (Saccharomyces cerevisiae) by high resolution cryo SEM
Authors: Walther P. , Hentschel J. , Herter P. , Müller T. , Zierold K. 
Published: August 2011

AbstractIn order to investigate the potential of high‐resolution cryoscanning electron microscopy (SEM), frozen‐hydrated bulk specimens were compared with transmission electron microscopy (TEM) freeze‐fracture replicas. For this purpose a field emission SEM was equipped with a cryo unit consisting of a cold stage in the electron microscopical column and a dedicated cryo preparation chamber. Baker's yeast, Saccharomyces cerevisiae, was the chosen test specimen. The hexagonally arranged intramembranous particles of the plasmic fracture face of the plasmalemma are well known from TEM freeze‐fracture studies and can be clearly discerned from structures deriving from preparation artifacts. After freezing, fracturing, sputter‐coating with 3 nm of platinum, and vacuum transfer to the cold goniometer stage, the 16.5 nm periodic structure was resolved in the cryo‐SEM. Also, intramembranous particles in the nuclear envelope are preserved. Typical artifacts of cryo‐SEM are water vapour contaminations and mass loss due to electron irradiation of ice. However, these artifacts are easily recognized and discerned from biological information. Specific advantages of cryo‐SEM of frozen‐hydrated specimens are: (1) In comparison to SEM of dried material, dehydration artifacts such as shrinkage can be excluded. (2) Compared with freeze‐fracture replicas, larger specimens are obtained because no replica cleaning is necessary.
A study of polyethyleneterephthalate (PETP) films by colour cathodoluminescence in the SEM
Authors: Nazarov M. V. , Nazarova T. A. , Saparin G. V. , Obyden S. K. , Viskov M. V. 
Published: August 2011

AbstractThe local cathodoluminescence (CL) of polyethyleneterephthalate (PETP) films has been investigated by means of the SEM. We observed a change in both the intensity and the wavelength of CL depending on the charge injected. The observed changes in the CL spectra of PETP films are irreversible. This makes it possible to employ such films as carriers of information recorded by a fine electron beam with a density of 108 bit/cm2.
Characteristic fluorescence correction for layered samples part I: Closed solution for film‐substrate combination
Authors: Göhler K. , Hänisch M. 
Published: August 2011

AbstractThe main difficulty in solving the corresponding integral expressions for characteristic fluorescence of layered samples consists in the choice of an advantageous approximation of the depth distribution function ϕ (z). In accepting a point source, a linear dependence, or a sum of weighted exponential moments to describe primary excitation, a closed mathematical treatment of secondary excitation effects is possible. Part I of this series is restricted to the frequent case of film substrate samples. The contributing factors of fluorescence excitation are calculated assuming a sum of weighted exponential moments for primary depth distribution and using dimensionless variables. The influence of the shape of primary depth distribution is discussed and can be shown to be less than 5% for bulk conditions.
Conditions for voltage contrast observation over passivated devices
Authors: Kodama T. , Koyama N. , Uchikawa Y. 
Published: August 2011

AbstractInspection of passivated microdevices using the scanning electron microscope (SEM) at a low primary electron energy has been increasingly studied. Previously we reported an empirical formula for conditions under which SEM observations over the passivation layer can be made without inducing serious charging disturbances. An investigation of charge balance between primary and secondary electrons was presented. The present work investigates the charging disturbance‐free conditions of PSG, SiN, and Si3N4 passivated devices and how they are affected by beam irradiation. The storage time of the voltage contrast is measured for various values of primary electron energy and incident angle.
A method for generating morphometric data using SEM and an automated television image analysis system for the investigation of cell borders
Authors: Gusev S. A. , Baryshnikova N. A. , Pyatetsky A. A. 
Published: August 2011

AbstractThe traditional silver nitrate impregnation method used for visualization of cell borders does not allow the study of intercellular relationships and fails to demonstrate features of cell microrelief. It is shown that osmium tetroxide impregnation of vascular tissue, emphasizing cell border lines, and a special image analysis program for the semiautomatic system IBAS 2 can be used together for the effective analysis of the fine structure and of the cell layer. Our investigations of the aortic endothelium using this complex method have confirmed the heterogeneity of aortic endothelial cells in health and demonstrated that the endothelium of different aortic regions displays differential responses to blood pressure elevation and, further, that a major factor underlying the alterations observed in endothelial cells in disease and hypertension is the differential degree of overlap of the neighboring endothelial cells.
Detectors for low voltage scanning electron microscopy
Authors: Autrata R. , Hejna J. 
Published: August 2011

AbstractTwo simple electron detectors (low and high take‐off angles) for low‐voltage scanning electron microscopy were built and tested. They contain large area scintillators with an applied high voltage and are able to detect backscattered electrons with high efficiency. These detectors also can record the sum of backscattered and secondary electrons. The primary beam of the microscope is screened from the scintillator high voltage by grids, which also permit switching from the BSE to the (SE + BSE) mode. The circular symmetry of the grids minimizes the influence of applied potentials on the primary beam. The use of the low and high take‐off detectors permits the detection of back‐scattered electrons emitted from the specimen surface into different ranges of take‐off angles.
Transmission and double‐reflection scanning stage confocal microscope
Authors: Dixon A. E. , Damaskinos S. , Atkinson M. R. 
Published: August 2011

AbstractA new confocal scanning‐stage transmit‐ted‐light and reflected‐light laser microscope is described. In addition to allowing confocal transmitted‐light imaging, this microscope has the unique feature of imaging both the top and bottom of a specimen in reflected light, with the two images in perfect registration. Only one detector is used; different imaging modes can be selected by simple rotation of the polarizers. Several confocal images are presented, chosen to illustrate the unique features of the instrument.
Quantitative electron probe microanalysis of nitrogen
Authors: Bastin G. F. , Heijligers H. J. M. 
Published: August 2011

AbstractQuantitative electron probe microanalysis of nitrogen has been performed on 18 nitride specimens in the voltage range of 4–30 kV. A conventional lead stearate and a new W/Si multilayer analyzer crystal (2d = 5.98 nm) were used simultaneously. The net peak count rates on the latter crystal were approximately 2.8 times higher than on the lead stearate crystal. In addition, significant improvements in the peak to background ratios were achieved, which proved critical when dealing with difficult nitrides such as ZrN, Nb2N, and Mo2N. A most conspicuous feature of the new crystal, however, is its effective suppression of higher‐order reflections in the wavelength range of N‐Kα. As a result, backgrounds are free of interfering lines and spectral artifacts, which facilitates accurate background determination. Two procedures for the analysis of nitrogen in the presence of titanium are also discussed. One procedure is based on the assumption that the area–peak factor (APF, integral k‐ratio/peak k‐ratio) of the N‐Kα peak in Ti–N compounds relative to a nitrogen standard (Cr2N) has a fixed value which can be used in order to separate the Ti‐ll peak from the N‐Kα peak. Extensive tests on a number of compositions in the Ti–N system have shown that it is possible to do quantitative analysis of nitrogen in Ti–N compounds with a relative accuracy of better than 5%. For very low levels of nitrogen (below 15 at%) the APF method was found unsuitable. In such cases, however, the well‐known multiple least‐squares digital‐fitting techniques appeared to do an excellent job. In order to account for the effects of peak shape alterations in the N‐Kα peak, all nitrogen spectra were recorded in integral fashion and compared with those of the Cr2N standard. The shape alterations for the N‐Kα peak were much smaller than for B‐Kα and C‐Kα radiations: The observed values for the area–peak factor relative to Cr2N differed less than 5% from unity. The present work has resulted in a database containing 144 integral k‐ratios for N‐Kα and 149 peak k‐ratios for the x‐ray lines of the metal partners in the nitrides. Our own Gaussian ϕ(pz) matrix correction procedure “PROZA,” used in conjunction with a set of improved mass absorption coefficients, yielded excellent results for the nitrogen data: An average value of kcalc/Kmeas of 1.0051 and a relative root mean square deviation of 3.99%.
The use of charging effects in Al/Al2O3 metal‐matrix composites as a contrast mechanism in the SEM
Authors: Borchert A. M. , Vecchio K. S. , Stein R. D. 
Published: August 2011

AbstractA technique is described to image two phases (alumina and spinel) within a metal‐matrix composite which takes advantage of charging effects that occur during examination in an SEM. Microscope and specimen parameters which affect the amount of contrast generated via charging are discussed, and imaging strategies are introduced to optimize the effect. “Model” metal‐matrix composite specimens were developed to verify the degree of charging in each phase.
3D characterization of the eutectic Au–Si alloy by using a nuclear microprobe
Authors: Demortier G. , Mathot S. 
Published: August 2011

AbstractThe quantitative analysis of silicon in gold is performed in the three dimensions by the spectroscopy of protons produced in various depths by scanning a microbeam of energetic deuterons. Owing to the high Coulomb repulsion of incident deuterons by heavy nuclei (like gold), proton emission can only be induced on light elements. The incident deuterons may approach silicon nuclei at a sufficiently close distance to be broken and to give rise to an emission of energetic protons. Measuring the energy of these protons leads to a quantitative method of analysis of silicon at various depths under the surface of the irradiated material. The spatial resolution in the three dimensions of space lies around 3 microns. Application is made to the study of eutectic gold‐silicon alloys formed, in situ, and used for the soldering of gold at a low temperature (400° C).
In vivo imaging of human teeth and skin using real‐time confocal microscopy
Authors: New K. C. , Petroll W. M. , Boyde A. , Martin L. , Corcuff P. , Leveque J. L. , Lemp M. A. , Cavanagh H. D. , Jester J. V. 
Published: August 2011

AbstractConfocal microscopy is currently being used to obtain images with higher lateral and axial resolution than conventional light microscopic techniques. Most current confocal microscopic applications describe the use of in vitro preparations. The tandem scanning microscope (TSM) can be applied in the in vivo microscopic evaluation of living tissue. This article discusses in vivo applications of the TSM in the study of human teeth and skin.
Characterization of chevron‐shaped permalloy magnetic memory elements by four magnetic imaging techniques
Authors: Cameron G. P. , Eberle W. J. 
Published: August 2011

AbstractScanning auger microscopy (SAM) and the recently developed scanning electron microscopy with polarization analysis (SEMPA) are easily combined analytical techniques which provide quantitative submicrometer images of X‐, Y‐, and Z‐axis spin polarization components of magnetization. SAM/SEMPA, along with three established magnetic imaging techniques (Bitter colloidal, longitudinal magneto‐optic Kerr microscopy, and the Fresnel mode of Lorentz microscopy), was used to characterize a chevron‐shaped permalloy magnetic memory element. Reflected light and secondary electrons were used to image the topography. Auger electrons identified and imaged the elemental composition. Reflected light, transmitted electrons, and secondary electrons were used to image the magnetic microstructure. The Bitter colloidal images showed only the delineation of the domain walls, and the longitudinal magneto‐optic Kerr microscopy images produced similar results. The Lorentz microscopy images provided the most qualitative magnetization information. SAM/SEMPA was the only technique to combine elemental information and quantitative magnetization information with images having submicrometer resolution.
New confocal LM method for studying local relative microrelief with special reference to wear studies
Authors: Boyde A. , Fortelius M. 
Published: August 2011

AbstractSubtracting a smoothed version of a digital map image from the unprocessed original leaves a map of the local surface relief. The map in question is obtained by through focussing with a confocal reflection microscope, retaining the focus value for the greatest signal level at each X,Y pixel address as the Z (height/depth) coordinate.