bluuebunny/crossref_metadata_2025_split huggingface dataset:
Relevance of Reflection in Static and Dynamic Light Scattering Experiments
Authors: Van Der Meeren Paul , Vanderdeelen Jan , Baert Leon 
Published: December 2004

AbstractUsing a monodisperse PMMA dispersion, it was shown that light reflection at the sample cuvette walls may greatly influence the results of both static (SLS) and dynamic (DLS) light scattering experiments. Considering SLS, this reflection phenomenon mostly causes an overestimation of the scattered intensity at high scattering angles, which may give rise to the emergence of an additional, artificial peak in the lower region of the particle size distribution. On the other hand, the influcence of reflection on DLS measurements was shown to be particularly important in the upper region of the particle size distribution. The experimentally observed phenomena were explained from the basic principles of both particle sizing methods. Finally, it was shown that the disturbing effect of reflection could be avoided by modifying either the hardware or the software of the static and dynamic light scattering technique.
Some Far‐Field Scattering Characteristics of Radially Inhomogeneous Particles
Authors: Kai Li , Massoli Patrizio , D'Alessio Antonio 
Published: December 2004

AbstractThe finely stratified sphere model was used to calculate scattered electromagnetic fields from radially inhomogeneous spherical particles illuminated by electromagnetic plane waves. The calculation results show that radial gradients of the real part of the refractive indices change the ray paths into curved lines inside large spherical particles, resulting in fluctuations of rainbow positions for droplets during heat transfer processes. The light intensity in the forward scattering region is found to be useful to infer information about the profile of the imaginary part of the refractive index.
Determination of Geometrical Properties of Mechanically Delaminated Ultrathin Talc Platelets
Authors: Ishimori Toshihiro , Yamashita Mika , Senna Mamoru 
Published: December 2004

AbstractThe three‐dimensional particle size and shape of mechanically delaminated talc thin platelets were determined by combining two different methods. The plate diameter was determined by microscopy with the aid of an image analyser and the thickness from the X‐ray crystallite size perpendicular to the basal plane. The net line broadening of the X‐ray diffraction peak, necessary for the determination of X‐ray crystallite size, was evaluated by electron microscopy. In order to correct X‐ray diffractometry for instrumental broadening, the platelet thickness of a representative specimen was obtained directly using a transmission electron microscope coupled with a laborious slice technique with an ultramicrotome.
Application of Fractal Geometry in Quantitative Characterization of Aerosol Morphology
Authors: Lee Chung‐Te , Chou Charles C.‐K. 
Published: December 2004

AbstractThe aerosol morphologies of six types of particles plus one other from a different source were characterized quantitatively in terms of fractal dimensions based on boundary, projected area and surface roughness. Except for the particle with a smooth boundary, multifractal features were observed on the projected boundary of aerosols. It was found that the fractal dimensions of the aerosol boundaries in the high‐resolution region ranged from 1.00 to 1.13, whereas those in the low‐resolution region were distributed from 1.04 to 1.91. The compactness of a particle could be examined in terms of the fractal dimension of its projected area such that a solid particle gave a value of 2.00, a hollow particle with pores inside gave a value of 1.93 and a chain agglomerate gave an even lower value of 1.81. Aerosol topological features retrieved from the gray levels of a microimage were used to illustrate the difference in surface roughness or distinguish particle deposition on the substrate from that of agglomeration. A value of 2.49 was found for a hollow sphere in contrast to a value of 2.26 for a round pollen particle. Finally, a coordinate system was established by employing the computed fractal dimensions as axes to accommodate the particles characterized in this work and the Euclidean distance of a point from the origin was shown to be a potential composite index for aerosol morphology.
Monodispersion of the Investigated Flow in the Sorting Unit of a particle size optical and electrical analyser
Authors: Ovod Vladimir 
Published: December 2004

AbstractThe use of a compact cylindrical piezoelectric transducer in the jet dispersion unit of the sorting system of an optical or electrical particle size analyser is discussed. Solving two equations for the shift distribution in a piezoelectric transducer with a running fluid chamber, important expressions for the vibrational velocity of acoustic terminal, mechanical impedance, of the stable part of the jet are obtained. The practical application of this technique is illustrated by the calculation of desi parameters for an industrial dispersion unit used in an H.cytophotometer (Ortho Instruments, USA). Good agreement between theoretical and experimental results is shown.
Modified glow discharge spectroscopy for surface analysis of steels
Authors: Ohashi Yoshiharu , Yamamoto Yasuko , Tsunoyama Kozo , Kishidaka Hisashi 
Published: December 2004

AbstractGrimm‐type glow discharge spectroscopy (GDS) was installed and evaluated as an emission spectroscopic source for the analysis of steel surfaces and for the determination of in‐depth concentration profiles. In order to restrict the abnormal intensity fluctuation at the surface layer, which was observed during analysis of 300 Å of the sample surface layer, the third electrode was installed in the light source and a preliminary discharge technique was developed. The purpose of this preliminary discharge is to clean the sample surface and inner wall of the anode pipe, and to produce plasma in the discharge chamber in order to start the main discharge smoothly. By using GDS with this technique (modified GDS) the influence of abnormal fluctuation at the first stage of discharge was completely excluded and the unstable region of the intensity profile at the beginning of discharge was restricted to 10 Å or so. This modified GDS was applied to the analysis of the surface of box‐annealed steel sheets and the determination of changes in composition with depth below the surface. The results were confirmed by an investigation of the in‐depth analysis of the same samples previously conducted with an ion microprobe mass analyzer (IMMA), and this fact revealed the usefulness of modified GDS as a surface analyzer.
Stress distributions and thin film mechanical properties
Authors: Hoffman R. W. 
Published: December 2004

AbstractNon‐uniform stresses exist near the edges of thin films as a result of satisfying the boundary conditions. Growth stresses also contribute to stress gradients within the film, especially in structures with a void‐columnar microstructure. As a result the strain‐sensitive properties also must show spatial variations which will become more important as the specimen size decreases. We examine the origin of these distributions within the limits of elestic behavior, and discuss cases for which the distributions have also been measured. The role of plastic deformation in relaxation and fracture is introduced.
Evaluating ratio data for the determination of reduced thicknesses by XPS
Authors: Ebel Maria F. 
Published: December 2004

AbstractXPS investigations of surfaces with overlayers of thicknesses smaller than 10 nm provide photoelectron spectra from the substrate and the overlayer. For determination of the reduced thickness of the layer it is most valuable to employ a ratio of integrated line intensities (nlayer/nsubstrate). The theory of the ratio method results in a ‘two unknowns’ problem (reduced thickness and a constant). For SiO2 on Si the constant is well known (0.67) and thus the thickness of the layer can be obtained by a measurement performed under one take‐off angle. Other experimental situations demand measurements under different take‐off angles and a least‐squares fit. It is shown how surface roughness influences the application of equations derived for ideally smooth surfaces. The use of these equations for photoelectrons with great differences in their energies is demonstrated.
Scanning Auger microscopy: Resolution in time, energy and space
Authors: Brooker A. D. , Castle J. E. 
Published: December 2004

AbstractFor the examination of dynamic experiments using scanning Auger microscopy, it is important to achieve optimum resolution in time, energy and space. For example, to study a solidification front moving through a pool of molten metal, time resolution is necessary to allow rapid analysis at the point of freezing (allowing perhaps compositional data to be included on a phase diagram), spatial resolution should be good enough to allow accurate positioning of the electron beam on the front, and energy resolution is needed to distinguish between elements and to determine chemical state information (if it is available).This work examines a series of pure metal standards using a V.G. Scientific MA 500—a high resolution scanning Auger microscope with a hemispherical analyser. This instrument allows spectra with good signal to noise ratios to be acquired in the pulse counted mode, acquisition being totally computer controlled. Hence the effect of spectrometer variables upon pulse counted spectra has been determined by analysing the standard metals under a wide range of conditions. It has proven possible in a number of cases, to derive relationships between the spectrometer conditions (which are under operator control) and the resultant spectra. From these relationships ‘resolution diagrams’ may be constructed, which define the acquisition conditions necessary to achieve the chosen resolution in any of its three modes. It is felt that the approach used in the construction of such diagrams could be used for any spectrometer configuration.
The quantitative measurement of Auger peaks in N(E) form
Authors: Underhill P. R. 
Published: December 2004

AbstractIt is pointed out that for highly accurate measurements, it is important that the standards and unknowns have similar elemental distributions over the escape depth of the Auger electrons. This requires that the total Auger spectrum, including no‐loss peak and low energy loss background be the same for the unknown and standards spectra. In this case, linear least‐squares fitting of the total electron spectrum about the Auger peak in the unknown spectrum, with standard spectra and an extra arbitrary straight line produce fast, accurate, statistically‐meaningful results.
Chromium chromate as an inert marker in copper oxidation
Authors: Day Robert J. , Frisch Margaret A. 
Published: December 2004

AbstractChromium chromate films applied to commercial copper foil as corrosion inhibitors are observed to move into the copper during heat treatment in air such as occurs during lamination of printed circuit boards. Chromium depth distributions measured using secondary ion mass spectrometry for foils heated at various times and temperatures show that this change in position of the chromium is not a result of diffusion of the chromium compound. Rather, the major phenomenon is outdiffusion of copper driven by its oxidation at the surface. The temperatures examined spanned one region in which copper oxidation was the rate limiting factor in the overlayer growth and a second region in which growth of the copper oxide overlayer was diffusion limited. Implications in circuit board manufacturing are discussed.
Variable angle XPS investigation of lubricant films coated on sputtered carbon
Authors: Swami G. T. K. 
Published: December 2004

AbstractThe thickness t of the fluorocarbon lubricant applied on the sputter‐deposited carbon substrates is measured using the uniform overlayer model

where γc is the mean free path of the C 1s photoelectrons in the lubricant, R is the experimentally measured intensity ratio of the fluorocarbon to the hydrocarbon components of the C 1s line, θ is the photoelectron take‐off angle, and a is the ratio of C 1s intensity from the lubricant‐free substrate to that from the bulk lubricant. A procedure for experimentally determining the a value, using a partially gold‐coated graphite substrate as a reference, is reported. Values of 4.1, 2.9 and 2.2 were obtained for a respectively on sputter cleaned substrates of graphite, carbon on silicon wafer and carbon on thin film magnetic recording disk. The lower a values of the deposited films are attributed to the presence of voids in the films. Oxidation causes a decrease in a by reducing the carbon content of the substrates, The experimentally determined a values are verifled by monitoring the relative variation in the C 1s and the F 1s signal intensities as a function of θ. The angle dependence of a is discussed.
Characterization of crystal surfaces, thin films and superlattices by brillouin scattering from surface acoustic modes
Authors: Elmiger M. W. , Henz J. , Känel H. V. , Ospelt M. , Wachter P. 
Published: December 2004

AbstractSurface acoustic waves on single crystals of Ge and Si, thin films of CoSi2 and epitaxially grown CoSi2/Si superlattices on Si (111) are investigated by means of Brillouin scattering. The angular dispersion of the hypersonic surface waves localized at the surface was measured and used to determine the elastic tensor.
Improved dynamic range and automated lineshape differentiation in AES/XPS composition versus depth profiles
Authors: Watson D. G. 
Published: December 2004

AbstractDepth profiles calculated using simple peak‐to‐peak or peak height or area measurements are subject to inaccuracies caused by spectral noise, sloping backgrounds and possibly by overlapping spectra of different elements or chemical species. An automated program that reduces or eliminates the effects of these potential sources of error in the peak heights and areas calculated from electron spectra has been developed. The program uses linear least‐squares fitting of one or more basis spectra to determine the peak height or area for each spectrum recorded during the profile. The program selects the basis spectra from the energy region data set without operator intervention. The number of unique lineshapes is determined by the program, again without operator intervention, and a profile is calculated for each species. The fit method of intensity determination was found to increase the dynamic range by reducing false contributions to the calculated intensities; this observation holds when a single basis spectrum is sufficient to model the data. Contributions from overlapping spectra are resolved if an example of each pure species lineshape is available in the regional data set. The method is demostrated by practical example.
Theoretical and experimental studies of the broadening of dilute delta‐doped Si spikes in GaAs during SIMS depth profiling
Authors: Badheka R. , Wadsworth M. , Armour D. G. , van den Berg J. A. , Clegg J. B. 
Published: December 2004

AbstractDelta‐doped structures represent a powerful class of test structures to investigate the experimental and fundamental factors limiting the depth resolution obtainable in SIMS sputter depth profiling.In this work, theoretical studies of the effects on the broadening of an Si delta spike in GaAs as a function of the energy (1.4–4.4 keV) and angle of incidence (2°, 45° and 60° off‐normal) of the O2 sputter probe beam have been compared with recent experimental data. The theoretical calculations were carried out using the newly developed IMPETUS computer code, which simulates the depth profiling process by taking into account the combined effects of ballistic mixing (treating collisional mixing as a diffusion process), projectile incorporation into the matrix and sputtering. All of these are processes that always occur in any practical sputter depth profiling situation.The IMPETUS model can reproduce low‐energy Si depth profiles with great accuracy by using the well‐established TRIM calculated range, energy deposition and sputtering data and by making reasonable assumptions for the threshold energy for diffusion in addition to assuming a beam‐ and sputter statistics‐induced surface microtopography, which is described by a Gaussian area versus height distribution having a standard deviation σ = 0.8 nm. Significantly, it is shown that the effects of these parameters on the shape of the sputter profile are largely independent, with σ (accounting for microroughness) mainly affecting the leading edge and the threshold energy (determining mixing processes) the trailing edge of the sputter profile. Good agreement on the energy dependence of the broadening is also obtained. The expected improvement in depth resolution with increasing off‐normal bombardment angle is confirmed and can be quantified. The error in the experimental depth scale calibration based on a constant sputter rate, ignoring transient sputtering, is evaluated. Finally, the sputter depth profile observed for an Si delta spike in GaAs subjected to thermal annealing during growth by molecular beam epitaxy (MBE) can be reproduced accurately by considering diffusion broadening of the initial spike followed by a sputter profiling simulation.
Image depth profiling SIMS: An evaluation for the analysis of light element diffusion for the analysis of light element diffusion in YBa2 Cu3O7–x single‐crystal superconductors
Authors: Gillen Greg , Kaiser Debra L. , Wallace Jay S. 
Published: December 2004

AbstractAn analytical strategy for quantifying the diffusion of 18O in small, melt‐grown single‐crystal Yba2Cu3O7‐x superconductors by image depth profiling SIMS is presented. This technique was used to obtain data for both in‐depth (along the c‐axis) and lateral (in theab‐plane) diffusion from one superconducting crystal. Cross‐sectional images, generated from the image depth profiling data, revealed features of the diffusion processes that would not have been apparent in a standard depth profile. Retrospective selected area depth profiling was used to remove the influence of background species, edge effects and imperfections in the crystals, resulting in processed depth profiles with greater dynamic range. These techniques also were used to study the diffusion behavior of fluorine that was unexpectedly incorporated into the superconduting crystals during preparation. Finally, the influence of detector artifacts on the analytical results was evaluated.
Detection limit for carbon in InSb during SIMS depth profiling
Authors: Galuska A. A. , Greulich F. G. 
Published: December 2004

AbstractSecondary ion mass spectrometry (SIMS) is commonly used to determine the depth distribution of carbon in semiconductors. Carbonaceous residual gases in SIMS insturumentation and memory effects associated with carbon redeposition within the sputtered craters normally limit the detectability of carbon to ∼ 1 × 1017 C cm−3. In this investigation, the effects of primary ion (Cs+ and O2+), primary ion current (also current density), secondary ion, secondary ion energy discrimination, cryogenic cold finger and vacuum on the SIMS analysis of carbon in InSb were examined and optimized. Under optimized analysis conditions, the detection limit for carbon was reduced to ∼ 1 × 1016 C cm−3. Detection of the 123SB12C− molecular ion rather than 12C− was found to increase the sensitivity to carbon by ∼ 3 ×. In addition, 123Sb12C− was found to be less sensitive to carbon contamination present on as‐received surfaces or incorporated from the analytical environment.
Peak identification for mass spectroscopy
Authors: Lareau R. T. , Buser C. H. , Savin W. 
Published: December 2004

AbstractQuick, accurate identification of mass spectral peaks is essential, whether the sample is in a gas, liquid or solid state. Often, the mass‐filtered ion spectra include peaks due to atomic, molecular, cluster or multiply charged species. The computer program discussed herein will provide an aid to the mass spectroscopist in identifying: (1) an unknown/interference mass peak; (2) possible overlapping (non‐resolvable) mass species; (3) the required mass resolution necessary to separate neighboring mass species. Other advantages include user selectable species, PC compatible software, unlimited mass range, and unlimited number of variables. Examples will presented for samples analyzed by secondary ion mass spectrometry (SIMS) and glow discharge mass spectrometry (GDMS), as well as indications for its use in general organic mass spectrometry.
The surface photo‐oxidation of polystyrene. Part II: The application of ToF‐SIMS to monitor changes in the surface chemistry of neat polystyrene films
Authors: O'Toole L. , Short R. D. , Bottino F. A. , Di Pasquale G. , Pollicino A. 
Published: December 2004

AbstractTime‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) has been employed to monitor the chemical changes occurring with continuous UV irradiation in the surface region of neat films of polystyrene and the copolymer of styrene and 2‐(2‐hydroxy‐3‐vinyl‐5‐methylphenyl)benzotriazole (HVB, 2% w/w). Previous conclusions concerning the relative rates of oxygen uptake of these systems have been confirmed. New data are presented that enable delineation of two different surface reactions and demonstrate activation of the polymer surface by HVB with respect to polymer degradation as well as oxygen uptake. Some conclusions are drawn concerning the mechanism by which this activation is achieved.
Optimum parameters for combined Auger‐ionization loss coincidence spectroscopy in the reflection mode
Authors: Gergely G. 
Published: December 2004

AbstractThe detection limit of AES can be improved by combined Auger‐electron loss coincidence spectroscopy (AES‐ILSCS) as proposed by Cazaux. Using an arrangement with two hemispherical analysers and large‐angle collectors, experimental parameters are optimized by (1) matching the energy windows ΔEs of the spectrometers to achieve a large peak/background ratio, (2) setting the angular positions to obtain identical sampling depths for AES and ILS and (3) tilting the sample and using an adjustable electron gun at glancing incidence to get a large ILS signal. False coincidence can be reduced by small ΔEs and using very fast detectors in the coincidence mode for post‐accelerated AES and ILS electrons. Based on Langeron's data, the estimated coincidence signal/false coincidence noise ratio is ∼1 for 10−4 Fe coverage on an Si substrate using 9 keV, 10 nA primary electrons and a Δt ≈︁1 ns coincidence interval. The detection limit can be improved by a factor of 102 with respect to conventional AES.
Improved images with the scanning photoelectron microscope at the national synchrotron light source
Authors: Ade Harald , Ko Cheng‐Hao , Johnson Erik D. , Anderson Erik 
Published: December 2004

AbstractWe present recent developments with the scanning photoelectron microscope at beam line X1A (X1‐SPEM) at the National Synchrotron Light Source. It was the first to demonstrate elemental and chemical imaging with primary photoelectrons and achieve submicron resolution [Appl. Phys. Lett. 56, 1841–1843 (1990)]. Subsequent improvements allow us now to acquire XPS images with lateral resolution approaching 0.1 μm. We have utilized the instrument to examine artificial structures such as microelectronic devices and describe here our preliminary work in the study of photon‐beam‐mediated chemistry on aluminum surfaces.