bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Fly Ash and Superplasticizers on the Rheology of Cement Slurries
Authors: White Elizabeth L. , Lenkei Maria , Roy Della M. , Tamas Ferenc D. 
Published: March 2011

AbstractCementitious slurries composed of an oil well cement, a high calcium fly ash, a low calcium fly ash, and three commercially available superplasticizers (two different sulfonated naphthalene formaldehyde condensates and a sulfonated melamine formaldehyde condensate)were mixed to contrast the two fly ashes and to determine the effectiveness of each of the superplasticizing agents. Most commercial superplasticizers and cements are relatively expansive; therefore a partial substitution by fly ash and other by-products represents a substantial savings in both quantity of chemical admixture required and energy consumption for the manufacture of cement. In the cement/fly ash mixtures of 100/0, 90/10, 60/40, 40/60, and 10/90, with both high calcium fly ash and low calcium fly ash, the mixture containing the low calcium fly ash was consistently less workable. The rheological properties of the high vs. low calcium fly ash mixtures were controlled by the differences in fly ash particle size and the presence of irregular large particles, rather than by the differences in chemistry between the two. The low calcium fly ash was the coarser material.
Progress and Prospects of Materials Characterization at Subnanometer Spatial Resolution using Finely Focussed Electron Beams
Authors: Isaacson Michael 
Published: March 2011

ABSTRACTThe prospects of microanalysis using 0.5 nm diameter electron beams are reviewed. This paper will discuss the various characterization possibilities with emphasis on incoherent imaging, energy loss spectroscopy and convergent probe diffraction. Some examples indicating characterization at a 0.5 nm lateral spatial resolution scale will be presented and we will conclude with a discussion of the limits of nanometer characterization.
Transmission Electron Microscope Investigation of Sputtered Co-Pt Thin Films
Authors: Alexopoulos P. , Geiss R. H. , Schlenker M. 
Published: March 2011

ABSTRACTThin films of Co-10 at% Pt, ranging from 15 to 90 nm in thickness, have been DC-sputtered at various temperatures on to carbon-coated mica, carbon substrates on copper grids, or (001) silicon single crystals under 3 μm pressure of Ar, using targets of the alloy in the hexagonal phase, at growth rates of 9 nm/min. The samples were investigated by TEM, using bright-and dark-field imaging, lattice imaging, selected area diffraction and both Fresnel and focussed Lorentz modes. The primary structure of the films was found to be hexagonal, with a = 0.255 nm and c = 0.414 nm. For the samples sputtered at room temperature, the grain sizes were on the order of 0.μm on carbon-coated mica and carbon-substrate grids, and approximately an order of magnitude smaller on silicon substrates. Heavy streaking along the [001] of the hexagonal matrix was observed on diffraction patterns for grains having the [001] parallel to the surface; this streaking was found to be associated with the presence of a high density of faults parallel to the (001). In films sputtered on to carbon-coated mica at 225 °C, where a substantial reduction of the coercivity is observed, the overwhelming majority of the grains had the (001) basal plane parallel to the surface. Lorentz microscopy showed the magnetic domain structure in films grown on silicon to be markedly different from those grown on the carbon substrates, and further changes occurred for the films grown at elevated temperatures.
Refractory Metals Growth on MBE GaAs
Authors: Bloch J. , Heiblum M. 
Published: March 2011

ABSTRACTNolybenum and tungsten metals have been grown on an MBE grown (100)GaAs at various substrate temperatures. RHEED technique was used in situ to analyse the crystalline structure and the growth mechanism of the mechanism of the thin metal films. It was found that Mo epilayers can be grown on the (100) GaAs at temperatures between 150–400°C. The epitaxal arrangement is (111)Mo || (100)GaAs with [011]Mo || [011] GaAs. Tungsten films are not growing epitaxially under similar experimental conditions.
Auger Sputter Depth Profiling Applied to Advanced Semiconductor Device Structures
Authors: Skinner D. K. , Hill C. , Jones M. W. 
Published: March 2011

ABSTRACTThe continuing miniaturisation of modern semiconductor devices is placing new demands on the spatial resolution of many existing assessment techniques. With device structures reduced to nm dimensions the need to optimise conditions for high resolution in-depth profiling is essential for accurate characterisation. In this paper we present Auger profiles of two micro-electronic structures and consider the choice of ion beam parameters necessary to minimise ion beam induced distortion. In VLSI (Very Large Scale Integration) technology where high dopant concentrations are ion implanted into shallow layer structures, Auger profiling can be used to establish dopant distributions accurately in the peak regions of the high dose implant. This information is shown to provide data for process modelling programmes.Also presented are profiles of MOCVD (Metal Organic Chemical Vapour Deposition) grown GaAlAs/GaAs superlattices with 70 Å repeat structures. Interface width measurements are of particular importance in this case where sharp interfaces are a pre-requisite for good device performance. These structures have been found to be very vulnerable to enhanced atomic mixing, a consequence of the small mass of the Al atom. The Al content of the GaAlAs determining the obtainable in-depth resolution.
Electron Spectroscopic Studies of Substoichiometric Tantalum Carbide
Authors: Gruzalski G. R. , Zehner D. M. , Ownby G. W. 
Published: March 2011

ABSTRACTXPS was used to determine core-level binding energies and valence-band structure for TaCx over the range 0.5 ≲ × ≲ 1.0. As x decreased, the carbonls binding energy (BE) changed very little, the carbon-2s BE shifted toward the Fermi level, the position of the p-d valence-band peak shifted toward the Fermi level more, and the tantalum-4d and -4f BE's shifted toward the Fermi level even more, about 0.16 eV for a change in × of 0.1. In addition, the valence-band spectra exhibited structure between about 1 and 2 eV BE, and this structure increased as x decreased. These observations are explicable in terms of charge transfer and the formation of occupied defect states associated with carbon vacancies.
Experimental Investigation of GaAs Surface Oxidation
Authors: Matteson S. , Bowling R. A. 
Published: March 2011

ABSTRACTExperimental observations of the surface oxide chemistry of GaAs are reported for various commonly used chemical surface preparations. Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), and ellipsometry were employed to obtain information regarding the stoichiometry, depth distribution, and oxide growth kinetics of thin surface oxides. Previous observations of the segregation in depth of Ga and As oxides are corroborated. Arsenic oxides tend to be found near the surface while Ga2O3 is found near the GaAs-oxide interface. The presence of elemental As was frequently detected at this interface, as well. Surfaces essentially free from oxide are shown to be produced by certain chemical treatments, and the state of the surface in the solution is inferred. It is shown that the GaAs surface oxide stoichiometry can undergo several changes in a short time when exposed to water and air. In addition, the characterization of the oxidation of GaAs by ozone in the presence of intense ultraviolet illumination is reported. The oxide primarily consists of Ga2O3 and exhibits an interesting growth kinetics: the thickness of the oxide proceeds at first linearly, then logarithmically, then parabolically. This behavior is explained in terms of various mechanisms which are dominant at different thicknesses of oxide.
On the use of Secondary Ion Mass Spectrometry in Semiconductor Device Materials and Process Development
Authors: Magee Charles W. , Botnick Ephraim M. 
Published: March 2011

ABSTRACTThis paper describes how secondary ion mass spectrometry can be used effectively in semiconductor device materials and process development. A short overview of the experimental technique is given followed by applications in the following areas:1) Basic research2) New Process Development3) Trouble-shooting current processing4) Analysis of competitor's devices.
Sims Characterization of Thin Thermal Oxide Layers on Polycrystalline Aluminium
Authors: Degreve F. , Lang J. M. 
Published: March 2011

ABSTRACTThermal oxide layers of different thickness (T = 3.5–18 am) covering polycrystalline aluminium sheets were investigated by dynamic SIMS in an ion microscope. Depth profiles of major elements (Al, O), segregated impurities in the oxide layer (Li, Na, Be, Mg) and implanted 18O were recorded for different operating conditions : energy, incident angle, chemical (Ar+ or O2+) and isotopic (16O2+ or 18O2+) nature of the primary beam and oxygen jet to saturate the surface.The main results are:- the shape of the depth profiles is very sensitive to operating conditions : the best depth resolution is obtained at low energy (2.5 keV) and the minimal distorsion with an O2 jet, even under O2+ bombardment. Deconvolution would be necessary to deduce the true depth profiles.- a tremendous enrichment (103 – 104) of the oxide to the Al bulk is observed for Li, Na, Be and Mg via an efficient diffusion mechanism during heat 425°C. Their depth distribution within the oxide layer is heterogenous with surface enrichment for Li and Na and sub-layer (towards the oxide/metal interface) for Be lateral distribution below the interface is also heterogeneous e.g. at the grain boundaries for Be and Na.- the depth profile of implanted 18O+ versus operating conditions and oxide thickness gives direct information on the dynamic oxidation of Al induced by O2+ sputtering in the first 20 nm.
In Situ Ion Implantation for Quantitative SIMS Analysis
Authors: Lareau Richard T. , Williams Peter 
Published: March 2011

ABSTRACTThe primary ion column of a secondary ion mass spectrometer (Cameca IMS 3f) has been used as an ion implanter to prepare calibrated standards, In situ for quantitative SIMS analysis, with an accuracy better than 10%. The technique has been used to determine oxygen concentrations in contaminated TiSi2 films by implanting a reference level of 18O into a portion of the film.
Microfocussed Ion Beams for Surface Analysis and Depth Profiling
Authors: Kingham David R , Vohralik P , Fathers D , Waugh A R , Bayly A R 
Published: March 2011

ABSTRACTSIMS microprobe analysis using a liquid metal ion source (LMIS) for the primary ion probe can give fast, sub-micron resolution, chemical imaging of matrix and trace elements. The high brightness and small source size of the LMIS is vital for this high performance. Using a new 30kV gallium ion micro-probe a spatial resolution of 50nm can be achieved with a probe current density in excess of 1 A/cm2. A newly configured SIMS instrument is described which incorporates either a gallium or caesium ion probe as well as a duoplasmatron for ultimate sensitivity and depth profiling performance. For small area, high spatial resolution, depth profiling a raster-scanned ion micro-probe is ideal. A quadrupole mass spectrometer gives a mass range of 1–800 or 2–1200 amu. Examples are presented of up to 50nm resolution SIMS imaging with both positive and negative secondary ions and up to 50nm resolution ion induced secondary electron imaging of a wide variety of samples including superconductors, steels, alloy fractures, optical fibres, integrated circuits, catalysts, polymers and biological specimens. The recent addition of framestore to the system has enhanced the imaging capability, allowing secondary electron and several different secondary ion images of a sample to be overlaid in contrasting colours.
Some Applications of SIMS and SSMS in Materials Characterization
Authors: Verlinden J. , Vlaeminck R. , Adams F. , Gijbels R. 
Published: March 2011

ABSTRACTSome applications of spark source mass spectrometry are given showing that this technique, often considered as suitable for bulk analysis only, can also be used for the determination of impurities in thin layers and for in-depth profiling in rather thick samples.Secondary ion mass spectrometry, in addition to its applications in surface- and in-depth analysis, can successfully be applied to quantitative analysis when using the matrix ion species ratio as an environment sensitive indicator, or when using the isotope dilution method.
Hydrogenation during Thermal Nitridation of SiO2
Authors: Kuiper A. E. T. , Habraken F. H. P. M. , Chen James T. 
Published: March 2011

ABSTRACTThe incorporation of nitrogen and hydrogen during nitridation of SiO2 was studied over the temperature range of 800–1000°C and for ammonia pressures of 1, 5 and 10 atm. The nitrogen content of the nitrided films was determined with Rutherford backscattering spectrometry. Nitrogen in-depth profiles were obtained applying Auger analysis combined with ion-sputtering. Hydrogen profiles in the films were measured using nuclear reaction analysis. Both the nitrogen and hydrogen incorporation were found to increase with temperature in this range. A higher ammonia pressure primarily increases nitridation of the bulk of the oxide films. Depending on the nitridation conditions up to 10 at.% of hydrogen may be incorporated. As distinct from the nitrogen profiles, the hydrogen in-depth profiles are essentially flat. The concentration of hydrogen in the films, however, was always found to be smaller than that of nitrogen : measured H/N ratios varied between 0.09 and 0.85, the smaller values being obtained for the thinner oxides and higher nitridation temperatures. The model previously postulated to explain the nitrogen incorporation during atmospheric nitridation of SiO2 proves to be valid at higher pressures as well. By considering the role of OH as reaction product of the nitridation process, the hydrogen results can be accommodated within the same concept. The model predicts a low H/N incorporation ratio for a thin surface and interface layer and a substantially larger ratio for the bulk of the film. If this prediction is correct, which seems to be indicated by the etch-rate behaviour of the nitrided oxides, then this would have considerable importance for the electrical properties of this material.
Growth and Composition of LPCVD Silicon Oxynitride Films
Authors: Habraken F. H. P. M. , Kuiper A. E. T. 
Published: March 2011

ABSTRACTSilicon oxynitride films with various O/N concentration ratios were deposited in a Low Pressure Chemical Vapour Deposition process from SiH2Cl2, N2O and NH3 or ND3. The resulting films were analysed with respect to their chemical compositions using a number of high energy ion beam methods. The results of the analysis are related to the growth kinetics. It is suggested that the SiH2Cl2 decomposes more difficult on growth surfaces which contain more oxygen. The effect is attributed to the larger electronegativity of oxygen compared to nitrogen.
Concentration Measurements and Depth Profiling of Phosphorus and Boron by Means of (p,γ) Resonant Reactions
Authors: Pruppers M. J. M. , Zijderhand F. , Habraken F. H. P. M. , van der Weg W. F. 
Published: March 2011

ABSTRACTSmall concentrations of phosphorus and boron in thin films have been measured by detection of proton induced prompt γ-rays. This technique is almost free of interference from other elements in the film or the substrate. Furthermore it is possible to obtain depth information without sputtering. The detection limit of both elements is around 100 ppm; depth resolution at shallow depths in silicon is about 50 nm in the case of boron, whereas it is better than 10 nm in the case of phosphorus.As an application of this method, the incorporation of phosphorus and boron in thin films of hydrogenated amorphous silicon is measured. The films were prepared in a glow discharge reactor by mixing PH3 or B2H6 with the SiH4/H2 gas mixture.
Influence of the Density of Oxide Particles on the Diffusional Behavior of Oxygen in Internally Oxidized, Silver-Based Alloys+
Authors: Sanchez F. H. , Mercader R. C. , Pasquevich A. F. , Bibiloni A. G. , Lopezgarcia A. 
Published: March 2011

ABSTRACTThis paper presents strong evidence for the influence of the density of oxide particles on the internal oxidation kinetics of silver based alloys. Measurements performed by Mbssbauer Spectroscopy, on 1 at% Sn in Ag alloys oxidized at temperatures between 523 and 823K, clearly indicate that the oxidation kinetics are described by a power law of the time with an exponent close to the unity for a high density of oxide particles (between 0.3 and 1.0×10−2 oxide particles per alloy atom). For low densities (<10−4 oxide particles per alloy atom), the exponent is close to 0.5). Previous kinetics measurements in AgIn alloys are shown to be in general agreement with this rule. These results can be interpreted on the basis of the existence of strain fields around the oxide particles, which produce a network of channels for easy oxygen migration when the density of oxide particles is high enough.
The Use of Energy Loss Structures in XPS Characterisation of Surfaces
Authors: Castle J. E. , Abu-Talib I. , Richardson S. A. 
Published: March 2011

ABSTRACTThis paper describes advances in the use of the energy loss background associated with individual photoelectron peaks. The subtraction of a Shirley-type background is now normal practice in quantitative XPS analysis. However, in the case of a composite peak containing features from differing depths the subtraction of a common background has a clear disadvantage: i.e. the proportion of background rise associated with each component should be different but is, in fact, fixed. A peak-fitting procedure is described which enables individual backgrounds to be used for each component. The method has been tested using evaporated overlayers and this enables a mean free path for electrons undergoing small energy losses (less than 10 eV) to be determined. The findings are in accord with those of Tougaard and Sigmund and suggest that the use of background intensities in conjunction with the peaks themselves enables the information depth of XPS to be extended by about 10%. A few observations on the behaviour and use in analysis of the large energy loss structure are made.The use of the findings to aid in characterisation of the near surface distribution of elements and ions is described for the following systems: the distribution within oxide films on alloys; the locus of disbondment of organic films on metals; and the surface contamination of surfaces removed from aqueous media.
Surface Electronic Function Properties Characterization from Defect Heterogeneity Dominated Specular/Glancing/Grazing Versus Bulk Transmission Small-Angle-Scattering(SAS) Diffraction-Pattern via the Static Synergetics Algorithm/Exprimental Model
Authors: Siegel Edward 
Published: March 2011

ABSTRACTThe ability of Static Synergetios,the universal,reversible,scalable mathematical algorithm/(used as an) experimental model, connecting external radiation small-angle-scattering diffraction-pattern/static structure factor SSAS (k),dominated by defect heterogeneities/clumps/clusters,to electronic (magniic,mechanical) complex,frequency-dependent electrical,dielectric, noise,optical…Function properties,can be enhanced by utilizing a comparison/difference of bulk transmission versus surface specular/glancing/grazing incidence small-angle-scattering diffraction-patterns.
Core-Level Electron Binding Energy Change of Evaporated Pd
Authors: Kohiki Shigemi 
Published: March 2011

ABSTRACTPositive core-electron binding energy shifts in small palladium clusters supported on cadmium telluride substrate are shown to arise from the initial-state effects those are more sensitive to cluster size than are the final-state properties and the mean valence band electron binding energy is primarily responsible for the Pd 3d5/2 electron binding energy in lower coverage region (Pd ≲ 1×1015 atoms-cm−2).
Depth of Penetration of the Plasma Fluorination Reaction into Various Polymers
Authors: Wildi Eve A. , Scilla Gerald J. , DeLuca Alan 
Published: March 2011

ABSTRACTThe surfaces of a variety of polymers presenting either primary, secondary, tertiary, vinyl or aromatic protons to the reactive gas environment were fluorinated by glow discharge treatment. Depth profiles of the plasma surface reaction were obtained by SIMS with oxygen ion sputtering. Further information was obtained from the appearance of ESCA traces of these substrates before and after the reaction.
Microstructural Study of Devitrified Amorphous Alloys
Authors: Vassamillet Lawrence , Maringer Robert , Carbonara Robert , Mccall James 
Published: March 2011

ABSTRACTSeveral amorphous alloys were subjected to thermal processing subsequent to their rapid solidification. These alloys have been characterized utilizing metallographic (optical, TEM, and SEM) and x-ray methods. Also, mechanical property evaluations have been made. The alloys exhibit extremely fine grain size; some have a high degree of preferred orientation and second-phase precipitates in the submicron size range. Most have good modulus, high yield and ultimate strength, high reduction in area but limited percent elongation.
Some Advantages of EDS Analysis in a 400 KV Electron Microscope
Authors: Suzuki S. , Honda T. , Bando Y. 
Published: March 2011

ABSTRACTThe dependence of the characteristic and bremsstrahlung X-ray counts, the peak to background (P/B) ratio and the spatial resolution on the incident beam energy between 100 keV and 400 keV were measured using a high voltage electron microscope (HVEM). The bremsstrahlung count decreases much faster than that of the characteristic count with the increase of the incident beam energy. The decrease rate depends on Z number. It is ascertained that the P/B ratio and the spatial resolution at 400 keV were 2 or 3 and 2.5 times better than those at 100 keV, respectively.
Electron Energy-Loss Spectroscopy in a 400kV Transmission Electron Microscope (TEELS)
Authors: Oikawa T. , Hosoi J. , Kokubo Y. , Bando Y. , Lehman J. L. 
Published: March 2011

ABSTRACTElectron energy-loss spectroscopy in the transmission electron microscopy (TEELS) is a powerful technique to investigate the “electron and atom interaction in specimen microareas”.This paper reports some experimental data of TEELS concerning specimen thickness effect and advantages of 400 kV TEM, and introduces newly developed digital processing of EELS spectra, which is a powerful technique to get the information from the specimen materials.
The Application of Analytical Electron Microscopy to Improving the Sensitization Resistance of Type 304 Stainless Steels
Authors: Betrabet H. S. , Clark W. A. T. 
Published: March 2011

ABSTRACTThe sensitization resistance of austenitic stainless steels can be improved by replacing some of the C with N. Electrochemical potentionkinetic reactivation (EPR) tests indicate that this is effective up to∼0.16 wt.%N, but that above this level sensitization is enhanced. Thermodynamic calculations indicate that N should continue to reduce sensitization up to at least 0.25 wt.%N, as it retards the growth kinetics of Cr carbides. Analytical electron microscopy was used to investigate this apparent conflict and showed that, while N did decrease the volume diffusion coefficient of Cr beyond 0.16 wt.%, an increase in the amount of discontinuous precipitation of carbides with increasing N was responsible for the sensitization at higher N levels.