bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization by XPS and XAS of supported Pt/TiO2CeO2 catalysts
Authors: Dauscher A , Hilaire L. , Le Normand F. , Müller W. , Maire G. , Vasquez A.
Published: May 2005

TiO2 and CeO2 are will known for inducing strong metal‐support interactions J(SMSI) of a different nature when used as supports for Pt catalysts. X‐ray photoelectron spectroscopy analysis of mixtures of TiO2CeO2 oxide supports (80:20 and 20:80) reveals at the surface a remarkable stabilization of cerium in the +3 oxidation state; the stabilization is more pronounced with lower cerium oxide concentration. X‐ray absorption spectroscopy measurements done on the LIII edge show the same variation as a function of cerium oxide concentration, but in the bulk the reduction is much lower. Cerium in Pt/TiO2CeO2 catalysts exhibits the same behaviour.
Application of nuclear methods to the study of transfer wear of PTFE on stainless steel and silicon
Authors: Lappalainen R. , Yang E‐L. , Hirvonen J.‐P.
Published: May 2005

Ion beam analysis techniques available at a low‐energy accelerator (<2.5 MV) were utilized to study the transfer wear in the sliding contact of three types of PTFE (Teflon) and stainless steel (AISI 316) or silicon. The methods used include nuclear resonance broadening, back‐scattering, deuteron‐induced reactions, forward recoil spectroscopy, etc. These non‐destructive methods were used to probe the main components of the transferred film and the surface impurities with high sensitivity and reasonable depth resolution (a few nm). These complementary nuclear methods give reproducible results without any special sample pretreatment for insulating polymer films that are a few atomic layers thick. With an optimized measuring geometry, the time of measurement required for a typical accuracy of 1% for the transferred amount was reduced to a few minutes.
Nuclear microprobe characterization of surface hardening by precipitation of chromium carbides after laser beam treatment of a NiCr substrate
Authors: Mosbah Michelle , Gosset James , Trocellier Patrick , Puig T. , Cantarel M. , Condat M.
Published: May 2005

Surface treatment by laser provides interesting solutions to the problem of accelerated wear of materials. The aim of the present study is the characterization of chromium carbide‐rich surface alloys after laser beam melting of an Ni70Cr30 carbon‐precoated substrate. Transmission electron microscopy investigation shows the structure of the carburized zone, and electron diffraction shows the type of carbides formed. Carbon profiling of the lasered surface was performed by nuclear microprobe using the 12C(d, p0)13C reaction; Ni and Cr (more precisely, the ratio Ni/Cr) were evaluated semi‐quantitatively by means of particle‐induced x‐ray emission. The specificity of the method and the experimental conditions are explained. Wear results are very satisfactory and close to those obtained by injection of chromium carbide powders into the laser beam in the case of a Nimonic alloy: wear rates are divided by two orders of magnitude.
Mixed‐Oxide electrode study by secondary ion mass spectrometry
Authors: Daolio S. , Facchin B. , Pagura C. , De Battisti A. , Battaglin G.
Published: May 2005

Recent interest in the study of dimensionally stable electrode anodes by means of analysis techniques opens up possibilities of improving knowledge on the electrocatalytic activity of mixed‐oxide electrodes. In this work we report the SIMS characterization of IrO2/TiO2 coatings by many positive and negative ion species identifications and depth profiles of the most significant species.
Quantitative time‐of‐flight secondary ion mass spectrometry of a perfluorinated polyether
Authors: Fowler David E. , Johnson Roboert D. , Vanleyen Dieter , Benninghoven Alfred
Published: May 2005

Quantitative determination of the molecular weight and composition of submicrogram of a perfluorinated polyether (PFPE) supported on Ag and Si substrates was from empirical relationships derived from the intensities of specific high‐mass (≥ 800 amu) fragmentation ions from time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS) measurements. These relationships are explained in terms of simple concepts regarding the process of volatilization, fragmentation and ionization in TOF‐SIMS. The results for both negative and positive ions are nearly independent of the substrate materials used, demonstrating that the high‐mass fragmentation ions in TOF‐SIMS may be useful generally for in situ quantitative analysis of PEPEs on non‐specific substrates. This is an important difference between the TOF‐SIMS fragmentation spectrum and the complementary TOF‐SIMS cationized molecular ion spectrum, which requires special sample preparation and/or substrates. In order to interpret the quantitative information available in the TOF‐SIMS fragment spectrum, it was absolutely necessary to characterize extensively the PFPE samples using NMR and TOF‐SIMS Ag+ ‐cationized molecular ion results. This characterization helped to demonstrate the power of TOF‐SIMS to do quantitative analysis and led to additional insight concerning the SIMS ion‐forming process for PFPE. This study represents one of the first attempts to make quantitative use of the high‐mass fragment ion intensities in SIMS studies of polymers, and presents a method for confirming the origin of the mass peaks in the spectra.
Surface modification of extended chain polyethylene fibres to improve adhesion to epoxy and unsaturated polyester resins
Authors: Chappell P. J. C. , Brown J. R. , George G. A. , Willis H. A.
Published: May 2005

Extended chain polyethylene fibres have been treated in ammonia and oxygen lo‐pressure gas discharges (plasmas) in order to enhance adhesion to epoxy and unsaturated polyester resins, respectively, and thus significantly improve fibre/resin interfacial properties in fibre‐reinforced polymer composites. Ammonia plasma treatment results in the incorporation of amine functional groups onto the fibre suface. The treated fibre surface has been analysed using XPS and spectrophotometric techniques. Extended chain polyethylene/epoxy composites made from ammonia, plasma‐treated fibres show a marked increase in interlaminar shear strength over composites made from untreated, corona‐treated or oxygen plasma‐treated fibres. The increase in fibre/resin adhesion after ammonia plasma treatment is confirmed by SEM observations of fracture surfaces, which show clean interfacial fracture surfaces in composites made from treated fibres. Fibres modified by oxygen plasma treatment contain a significant concentration of carbon‐oxygen functionalities, which contribute to the polarity of the surface and hence increase wet‐out by unsaturated polyester resins. The concentration and nature of carbon‐oxygen species on the fibre surface have been determined by XPS. Pull‐out tests on multifilament yarns embedded in a polyester resin confirm the high fibre/matrix adhesion achieved with the oxygen plasma‐treated fibres compared to corona‐treated or untreated fibres. Tensile properties of the fibres are reduced significantly after prolonged treatment in an oxygen plasma, while in an ammonia plasma the fibre strength is unaffected.
Quantitative SIMS of III‐V compounds of graded composition without the use of standards
Authors: Crapper M. D. , Chew A. , Bradley R. H. , Sykes D. E.
Published: May 2005

A method is proposed for obtaining the matrix element SIMS sensitivity factors for III‐V compounds of the form ABxC1–x without using standards. This method tests for variation of sensitivities with concentration and, in the case where no strong variation is shown, allows determination of the sensitivity functions by use of samples where the concentrations of two elements vary continuously over a wide range. This method provides a no‐standards route to quantification of matrix element concentrations in SIMS depth profiles of layers with graded compositions.
Thickness dependence of the characteristic X‐ray yield and the Auger backscattering factor
Authors: Ei Gomati M. M. , Ross W. C. C. , Matthew J. A. D.
Published: May 2005

A Monte Carlo model employing a screened Rutherford scattering cross‐section and the Bethe energy loss approximation has been used to investigate the thickness dependence of the backscattering coefficient, η, the depth distribution of inner shall ionization, ϕ(ρz), the surface ionization function, ϕ(0), the Auger backscatter factor, r, and the initial gradient of the ϕ(ρz) curve, dϕ(0)/dz. Backscatter coefficients obtained for thick samples are in good agreement with experiment with experimental values. The surface ionization functions for C, Al, Cu, Ag and Au display an S‐shape thickness dependence, which is explainable in terms of the different scattering behaviour for samples of high and low atomic number. A direct relationship between the normalized surface ionization function, ϕ(0), and the Auger electron backscattering enhancement factor, r, is found, and a preliminary investigation has been made into the target thickness dependence of dϕ(0)/dz.
SIMS profile simulation using delta function distributions
Authors: Clegg J. B. , Gale I. G.
Published: May 2005

SIMS profiles of abrupt dopant distributions in semiconductor materials contain distortions introduced by the measurement process. In quantitative depth profile studies, it is important to determine and remove these errors.

We have used the idea that a given input profile may be represented by a series of adjacent delta‐doped planes. Given a knowledge of the SIMS obtained form one single plane (the resolution function), it is possible to simulate the expected SIMS profile form a given input profile by the convolution with the resolution function. Experimental data have been obtained form special samples of molecular beam epitaxial GaAs containing both delta‐doped planes and uniformly doped regions (1–20 nm thick). The dopants investigated were Si, Be and Al. It is shown that the simulated and experimental profiles of the uniformly doped regions show good agreement, thus demonstrating the validity of the method. We also present results of the convolution of an input function having exponential decays on the leading and trailing edges, which show the corrections that should be made to experimentally determined profiles. Additional simulations have been made with Gaussian inputs, which are relevant in dopant diffusion studies, Silicon diffusion lengths as small as 4 atomic planes (1.1 nm) have been deduced.
Quantitative resolution of X‐ray photoelectron spectra of mixtures of chromium compounds by the Kalman filter after cubic spline background removal
Authors: Malitesta C. , Rotunno T.
Published: May 2005

The potential of a new procedure for the quantitative analysis of ESCA spectra was exploited by determining the composition of powder mixtures of some chromium compounds. The quantitative separation of the overlapped Cr 2p peak doublets was accomplished by the Kalman filter algorithm. Background removal from the spectra was carried out by a new approach employing the cubic splines as smooth interpolators between the peak valleys. The results of the analyses compared well with those obtained by factor analysis (typical errors were ±4%). However, the Kalman filter operating recursively on the data points of the spectrum is preferable when the analysis is limited to only one mixture plus standards. Cubic spline interpolation was as effective as the Shirley method in yielding quantitative background subtraction.
XPS and SIMS studies of biodegradable suture materials
Authors: Brinen J. S. , Greenhouse S. , Jarrett P. K.
Published: May 2005

XPS and SIMS have been used to examine the surface composition of copolymers of glycolide (cyclic dimer of glycolic acid) and trimethylene carbonate (TMC) as solvent‐cast films. XPS results on the polymers agree with bulk composition data. SIMS measurements suggest surface enrichment of the TMC component.
A novel practical approach to the quantification of Auger electron spectroscopy
Authors: Mischler S. , Bishop H. E.
Published: May 2005

We describe here a novel practical approach for the quantification of AES based on normalization of the peak height to the background measured at a fixed energy.

Studies from the literature show that the background has an angular dependence close to the for the AES peak and it is directly proportional to the primary electron current. In addition, we have found that for a primary beam energy of 10 keV the background measured at 2 keV exhibits practically the same atomic number dependence as the back‐scattering factor. Therefore, we have proposed that normalization of the peak height to the background allows us to determine the absolute surface concentration of an element without reference to the other elements present, provided that the mean free path is known.

This proposal has been tested buy making measurements on a range of oxides, silicon compounds and metals. A good correlation is found between the O KLL peak‐to‐background ratio and the atomic concentration of oxygen in a series of oxides covering a wide range of atomic number (Mg to U). A similarly good correlation is observed for magnesium, silicon, iron and nickel Auger peaks.

The physical basis and the limitations of this quantitative approach are discussed.
Composition of thin surface layers obtained by X‐ray photoelectron spectroscopy
Authors: Watton H. L. L. , Fitzgerald A. G. , Moir P. A.
Published: May 2005

The surface composition of a solid may vary considerably from the bulk composition of the material. For example, surface contaminants such as carbon, oxygen, sulphur and chlorine can be present as a thin overlayer. Recently, procedures have been developed that enable determination of the composition, thickness and surface coverage of a thin overlayer on a surface from AES spectra. In the present work, a similar procedure has been developed for analysis of thin overlayers by XPS. The calculation deals with two possible situations, the overlayer either does or does not contain elements that occur in the underlying material. The composition, thickness and surface coverage of a number of overlayers have been investigated, including the surface contaminant layers on amorphous silicon films, a series of amorphous silicon nitride films with varying atomic ratios of silicon and nitrogen and vacuum‐deposited gold films on amorphous silicon nitride substrates.
Detection limits of surface contamination analysis by nitrogen‐RBS
Authors: Weidhaas Jens , Lang Walter
Published: May 2005

Owing to the development of thin‐film, semiconductor and clean‐room technologies, there is an increasing demand for the measurement of trace elements on surfaces. Rutherford backscattering spectroscopy using nitrogen ions is a powerful tool for this purpose. For heavy elements, e.g. gold, in silicon a surface sensitivity of 1010 atom cm−2 is reached. For medium elements, e.g. As, Cr and Fe, the detection limit is at 1012 atom cm−2.
Application of surface analysis techniques to the study of paint/metal interfaces related to adhesion and corrosion performance
Authors: van Ooij W. J. , Sabata A. , Appelhans A. D.
Published: May 2005

Interfaces between galvanized steel and automotive cathodic electrocoat paint systems were characterized by imaging XPS and static SIMS, using time‐of‐fight SIMS and quadrupole SIMS with an SF6 primary source. Variables were the pretreatment of the metal (phosphate coating) and the cure state of the pain system. Analyses were carried out prior to and following exposure in an accelerated cyclic corrosion test. In systems without phosphate pretreatments, severe delamination was observed in non‐corroded areas. In such areas, zinc hydroxycarbonate was found at the interface. In corroded areas, adhesion was retained, probably as a result of an interaction between cathodically generated O− ions and the paint. In phosphated systems, an undercure of the paint led to an increase of the underfilm corrosin. Static SIMS analysis of the paint/metal interface demonstrated that the state of cure of cathodic electrocoat systems can be detected by this technique and, furthermore, that certain paint constituents are preferentially adsorbed on the metal surface. The degree of cure of the paint was shown to change in going from the air/paint surface to the buld and on to the paint/metal interface. The adhesion behaviour of epoxy electrocoat systems to metallic substrates can be described in terms of acid–base interactions.
Non‐destructive characterization of polymer/metal interfaces using surface‐enhanced Raman scattering
Authors: Boerio F. J. , Hong P. P. , Tsai H. W. , Young J. T.
Published: May 2005

Surface‐enhanced Raman scattering (SERS) is an analytical technique in which the Raman scattering cross‐sections of molecules absorbed onto the roughened surfaces of certain metals are enhanced by as much as six orders of magnitude compared to their value for normal Raman scattering. The mechanisms are associated with the large electric fields that can be induced at the surfaces of metal particles having small radii of curvature and with the formation of charge‐transfer complexes between the adsorbed molecules and the substrate. Enhancement due to the charge‐transfer mechanism is obtained only for molecules immediately adjacent to the surface, but enhancement due to the electromagnetic mechanism may extend several monolayers away from the surface. Since normal Raman scattering by polymers is weak and scattering by molecules adjacent to the substrate is strongly enhanced, SERS can be used for non‐destructive characterization of interfaces between polymer films and metals as long as the films are not so thick that scattering by the bulk of the film is comparable in intensity to SERS from the interface.

We have used SERS to examine the interface between silver and an acrylic adhesive system consisting of an acrylic monomer and a cure system comprising cumene hydroperoxide (CHP), acetylphenylhydrazine (APH) and saccharin. SERS spectra obtained from films of the adhesive spin‐coated onto silver island films were similar to normal Raman spectra of salts of saccharin, indicating that saccharin had adsorbed on the silver dissociativly. The spectra were independent of the thickness of the adhesive films, indicating that the SERS signal was characteristic of the interface and not of the bulk adhesive.

SERS has been used also to characterize the interface between silver and pyromellitic diimide (PMDI), a model compound for polyimides. SERS spectra of PMDI adsorbed onto silver were considerably different from normal Raman spectra. The strongest band in the normal spectra, a carbonyl stretching mode near 1770 cm−1, was absent from the SERS spectra and a band near 700 cm−1, which was very weak in normal Raman spectra, was strong in SERS spectra. It was concluded that PMDI was adsorbed in a vertical conformation with one imide group adjacent to the surface.
XPS studies of the bonding and hydrolysis of dentine bonding agents
Authors: Williams R. L. , Ali S. A. M. , Williams D. F.
Published: May 2005

X‐ray photoelectron spectroscopy has been used to analyse the surface chemistry of dentine, the surface coverage of dentine by an experimental dentine bonding agent and the commercially available gluma Bond system and the hydrolysis of these adhesives. The cut dentine surface is shown to be of high inorganic composition. When this surface is treated with ethylenediaminetetracetic acid, the inorganic component was significantly reduced. The two adhesives were shown to spread effectively on the treated dentine surface and, following incubation in an aqueous environment, neither bonding system appeared to exhibit significant hydrolysis.
Background removal in AES; influence of detection geometrical characteristics
Authors: Rosenberg N. , Tholomier M. , Vicario E.
Published: May 2005

In order to remove the inelastic background from Auger spectra, we took advantage of theoretical work assuming an experimental arrangement corresponding to cylindrical symmetry. The knowledge of the inelastic differential cross‐section K(T) is necessary for the background calculation (T is the energy loss), so we calculated K(T) from back‐scattering spectra experimentally obtained using either a cylindrical mirror analyzer (cylindrical symmetry) or a hemispherical mirror analyzer (no cylindrical symmetry). The strict application of theoretical expressions may eventually lead to a K(T) function with some negative part, i. e. without physical meaning. We have interpreted this effect and we consequently succeeded in eliminating any negative part. In setting out the Auger spectra background, we took into account secondary electrons created by Auger electrons by introducing distinct laws for the spectra from the two analysers. ‘Intrinsic’ Auger spectra, obtained from elemental materials (Si, Ag, Ni, Cu) andregistered from either analyzer, were compared. Some minor differences remain, according to which analyzer is used.
Study of the reduced In2O3/μc‐Si:H interface by means of factor analysis
Authors: de Nijs J. M. M. , Aarts R. G. K. M.
Published: May 2005

The overgrowth of an In2O3 layer by a μc‐Si:H layer, deposited by means of plasma‐enhanced chemical vapour deposition, will inflict the reduction of the In2O3. AES is combination with Ar+ depth profiling is used for the study of the interfacial deterioration that takes place. The results of a factor analysis study after reduction of the In2O3 are presented.
The Auger parameter, polarization energies and electronegativities: Application to a series of non‐conducting barium slats
Authors: Berrie C. L. , Langell M. A.
Published: May 2005

By use of the Auger parameter, we show that barium in a series of halogen and chalcogenide slats presents chemically distinct and identifiable states. Differences between Auger parameters are related to the ligand environment and can be used to obtain information on extra‐atomic relaxation, at lest some of which is non‐local in origin in this series of barium slats. As has previously been demonstrated by Moretti, non‐local contributions to the extra‐atomic relaxation correlate directly with nearest‐neighbor anion polarization energies. However, polarization energies are easily calculable only for simple distributions of identical ligands. We present an alternative correlation between the Auger parameter and electronegativity, which can easily be performed regardless of structural complications and which shows a high degree of precision.
Application of tandem analyser to SIMS studies of hydrocarbon polymers
Authors: Leggett G. J. , Briggs D. , Vickerman J. C.
Published: May 2005

The fragmentation of ions sputtered from the surface of low‐density poly(ethylene) (LDPE) has been investigated by studying their collisionally activated dissociation (CAD) when incident upon a variety of target gases in the collision cell of a triple quadrupole SIMS instrument. It was found that heavier targets resulted in more extensive CAD than was observed with lighter targets but that sulphur hexafluoride is inefficient target because of the amount opf energy that is transferred to its vibrational modes of motion (rather than being available to induce fragmentation in the parent ion.) The behaviour observed for an oxygen target was quite different to that observed for other targets (at higher pressures). In general oxygen induced markedly greater fragmentation for the small parent ions but xenon was the preferred target for the larger parent ions. Fragmentation patterns could readily be assembled for all of the parent ions observed in the SIMS spectrum of LDPE using the CAD data. There are good indications that the data obtained may assist in indentification of ion structures and in elucidation of general rules governing the fragmentation of organic materials during SIMS. For example, LDPE fragment ions were found to obey quite strictly the Even Electron Rule, a well‐known rule in mass spectrometry.
XPS Studies of characterized Cu/Al2O3, Zn/Al2O3 and CuZn/Al2O3, catalysts
Authors: Moretti Giuliano
Published: May 2005

By XPS it is confirmed that copper‐containing catalysts supported on alumina and calcined at high temperature (673–873 k for 24 h.), with or without zinc addition, have a ‘surface spinel’ structure.

Combining the XPS results with previous results obtained by vis–UV reflectance spectroscopy and XRD we show that the limit of solubility of Zn and Cu ions in γ‐alumina, at a calcinations temperature of 873 k, about 20 and 10 wt.% (by weight), respectively. In the CuZn/Al2O3, catalysts prepared from Zn/Al2O3, a surface enrichment of copper occurs if the Zzinc ions are already presents in an amount larger than the surface solubility. The presence of zinc on the surface increases the reducibility under H2 of the Cu(II) ions compared to the same ions in the pure copper surface spinel. This may be due to the role of Zn(II)O(II) aggregates in the activation of the hydrogen molecule and/or to the segregation of CuO species on the Zinc surface spinel.
Spectroscopic cell for investigations of thin liquid films
Authors: Boinovich L. B. , Emel'yanenko A. M.
Published: May 2005

A special cell for investigation of the alterations in the transmittance spectra of thin liquid films during their thinning has been designed. The cell described enables one to investigate liquid interlayers with thicknesses from 10 nm to a few microns. A method for the evaluation of thicknesses of film according to the transmittance spectra has been developed.
Characterization of a thin copper film to investigate microbial biofilm formation
Authors: Bremer Philip J. , Geesey Gill G. , Drake Barney , Jolley John G. , Hankins Michael R.
Published: May 2005

Copper films, 6.7 nm nominal thickness, deposited by physical vapor deposition on germanium substrates appeared as coalescing aggregates of copper atoms when evaluated by atomic force microscopy. Evaluation of the Cu thin film by x‐ray photoelectron spectroscopy indicated that the Cu at the surface of the film had the character of a 1 + oxidation state. These features were not significantly changed when the Cu thin film was exposed to ethylene oxide. No Ge signal was detectable prior to XPS depth profiling through the Cu thin film, indicating that the film was continuous. When films of this thickness were deposited on a cylindrical Ge internal reflection element and subsequently submerged in an aqueous medium, there was sufficient transmission of infra‐red radiation through the Cu to obtain a significant water absorption band at 1640 cm−1. The intensity of the water absorption band was found to be very sensitive to changes in thickness of the copper thin film. This feature can be used to study the effect of microbial biofilms and their products on the integrity of oxidized copper surfaces in aqueous environments.
Angular intensity modulation in angle‐resolved XPC and AES of non‐crystalline ultrathin surface layers: The phenomenon and its implications
Authors: Gries W. H.
Published: May 2005

The well‐known phenomenon of forward (elastic) scattering of x‐ray photoelectrons and Auger electrons, which gives rise to prominent diffraction peaks for emission from monocrystalline materials, can lead to a much less prominent, yet significant, angular intensity modulation of emission from nominally non‐order materials in which stoichiometric or other constraints enforce some short to medium‐rang order. A seemingly small intensity modulation can have a drastic effect on the determination of layer thickness or of effective attenuation length from angle‐resolved measurements. This conclusion is arrived at by applying the known facts o forward scattering (summarized here) to the currently structural model of oxide layers on the semiconductors Si and GaAs (serving as examples). The predictions are compared with experimental data on carbonaceous contamination in the native oxide layers on Si (111) and GaAs (001), obtained by angle‐resolved XPS and AES and evaluated for angle‐dependent effective attenuation length. It is concluded that angular intensity modulation can be expected to be a frequently occurring phenomenon with serious implications for the study of ultrathin layers and ultraslow depth profiles by the electron spectroscopes XPS and AES.
AES depth profile study of a GaAs/AlAs superlattice
Authors: Kačiulis S. , Plešanovas A. , Tvardauskas H.
Published: May 2005

The width of the interface between sublayers in a GaAs/AIAs superlattice was investigated using AES combined with Ar+ ion sputtering and chemical etching. The factors stipulating the experimental broadening of the interface width were estimated. The real interface width, determined for a GaAs/AIAs superlattice grown by metal organic chemical vapour deposition (MOCVD), did not exceed three AIAs lattice constants. The influence of the sputtering ion beam energy to the experimental interface width, caused by surface roughness, was investigated. It was demonstrated that combination of the initial chemical etching or high‐energy ion sputtering with further low‐energy sputtering allowed deep sub layers to be investigated faster and without loss of depth resolution.
X‐ray photoelectron spectroscopy analysis of copper and zinc oxides and sulphides
Authors: Deroubaix G. , Marcus P.
Published: May 2005

Various copper and zinc compounds (Cu, Zn, CuZn alloy, Cu2O, CuO, Cu2S, ZnO, ZnS) have been synthesized and characterized by electron spectroscopy (XPS). Data on the 2p3/2 levels of Cu, Zn and S, the 1s level of O, the L3M45M45 Auger transitions of Cu and Zn, the valence bands and the modified Auger parameters are reported. The results obtained with these reference compounds allow qualitative and quantitative interpretation of XPS analyses on mixtures of these compounds.
Secondary ion mass spectrometry—first microelectronics, now the rest of the world
Authors: Stevie F. A.
Published: May 2005

Secondary ion mass spectrometry (SIMS) has achieved great success as a materials characterization tool because of its parts‐per‐million to parts‐per‐billion sensitivity and excellent depth resolution. SIMS is best known for applications in the semiconductor industry, but is increasingly used in many other fields. Despite this growth, three myths persist regarding SIMS: the technique is not quantitative, insulators are difficult or impossible to analyze and good depth resolution cannot be obtained for metals. Recent work by several groups should dispell these misconceptions. Quantification with a reproducibility and accuracy of 10–20% is commonplace with ion implantation calibration methods. Patterns for secondary ion yields of the elements when plotted against ionization potential and electron affinity have been identified in a number of semiconductor and metal matrices. The pattern similarities allow sensitivity factors to be estimated for elements for which an implanted calibration is not available. The Lawrence Livermore project of selected elements into 200 matrices is expected to extend this concept to oxides, minerals, alloys, ceramics and fluorides. The analysis of insulators has been made routine by the use of an electron beam for charge neutralization and an understanding of the placement of the electron beam and the electron to ion current density ratio required. The glass industry provides many applications for this capability. Metals and other polycrystalline materials can be sputtered evenly if the sample is rotated during ion bombardment. This rotation method has been used for matrix‐level species in Auger analysis, and has now been shown to be viable in SIMS at the parts per million level.
Auger and x‐ray photoelectron spectroscopy study of localized intergranular cracking in a nickel—chromium—molybdenum—iron alloy
Authors: Bradbury C. A. , Sturgill K. E. , McKissick D. C.
Published: May 2005

An unused jet engine tailpipe, fabricated from a nickel—chromium—molybdenum—iron alloy, was found to be severely embrittled after 7 years of storage. Metallurgical and mechanical tests found a larger than specification size grain structure and several very localized areas of unexplained low ductility. These were surrounded by material with normal properties. Auger electron spectroscopy (AES) studies documented the elemental composition and relative concentration at the grain boundaries. Sodium, chlorine, sulfur, iron, chromium, nickel and carbon were present. The concentration of the iron was much higher than expected, while the nickel concentration was significantly lower. The concentrations remained at these levels through 90 min of ion sputtering. X‐ray photoelectron binding energies of iron and carbon indicate that these elements were present as carbides. The presence of an abnormal chemistry at the grain boundaries, such as iron carbides, was considered to be the probable cause of the embrittlement.
Effects of morphology on the electrical and optical properties of thin bismuth films
Authors: Christensen T. M. , Dalton D. I.
Published: May 2005

Thin films of bismuth were evaporated onto polished Si(100) substrates at substrate growth temperatures which varied between 25 and 100° C. The variations in film morphology observed using the scanning electron microscope and atomic force microscope were compared to changes in the optical and electrical properties of the thin Bi films. The optical properties could be modeled using an effective medium approximation, which suggested that the roughness of the films changed with substrate growth temperature. The film roughness appeared to decrease with substrate temperature from room temperature deposition to a minimum roughness at temperatures of ∼70 °C. Higher temperatures again resulted in an increased roughness, which correlated with a change in morphology observed by SEM. The electrical resistance of the samples was not sensitive to roughness changes in the film, but did change abruptly for the higher temperature samples where the morphology was substantially different. The transverse magnetoresistance was sensitive to film structure, increasing with substrate growth temperature up to a maximum substrate temperature of 70 °C before decreasing again at higher temperatures.
Langmuir‐Blodgett films of rigid rod oligoimides on gold: An x‐ray photoelectron spectroscopy study
Authors: Atanasoska Ljiljana , Cammarata Vince , Stallman Barbara J. , Kwan Wing Sum V. , Miller Larry L.
Published: May 2005

Angular‐resolved x‐ray photoelectron spectroscopy (ARXPS) was used to study mono‐ and multilayer films of rigid oligoimides prepared on gold‐coated glass slides by the Langmuir‐Blodgett (LB) horizontal lifting technique. The experimentally obtained total atomic ratios were in a good agreement with molecular formulae. The attenuation of the substrate Au 4f photoemissio intensities was recorded as a function of both the number of LB dips and the take‐off angles. The ratio of the thickness to the attenuation length was determined for three different oligoimides from the slopes of the linear attenuation regions. Interpretation of the thickness/attenuation length ratio was based on the models for the oligoimide LB films of oriented structures. The average tilt angle and the area/molecule used in modeling the oligoimide film structures were determined in independent experiments involving grazing angle infrared (GIR) spectroscopy, electrochemistry and LB pressure‐area isotherms. The thicknesses of the oligoimide films were calculated from the models and used to derive the value of the attenuation length from the ARXPS slopes. The attenuation length value for Au 4f core‐level photoelectrons (Ek = 1169.6 eV) was estimated to be 66–70 Å in the LB films of all three different oligoimides.
The use of metal/semiconductor structures to develop MULSAM analytical techniques
Authors: Prutton M. , Barkshire I. R. , El Gomati M. M. , Greenwood J. C. , Kenny P. G. , Roberts R. H.
Published: May 2005

The structures that can be fabricated by integrated circuit technology are very useful as well‐characterized samples for testing image processing methodologies in multi‐imaging instruments. Such samples are employed in the work described in this paper to evaluate schemes for correction of spectral background, substrate backscattering, surface topography and beam current fluctuation effects out of Auger images. The outstanding problems associated with the effects on Auger image contrast of sharp edges bounding overlayer structures are outlined and possible solutions are discussed.
Characterization of the annealed CoTi (110) surface and its interaction with molecular oxygen at room temperature
Authors: Rivière J. C. , Netzer F. P. , Rosina G.
Published: May 2005

The annealed surface of CoTi single crystal oriented (110) has been characterized by AES, low‐energy electron diffraction (LEED) and electron energy‐loss spectroscopy (ELS), and the nature of its interaction with molecular oxygen at room tempertature has been studied. In the cleanest achieveable condition (5a/o oxygen irreducible minimum), the AES and LEED observations were consistent with a model in which the outer two atom layers consisted of titanium in registry with the underlying CoTi (110). Support for the model came from ELS, in which the titanium plasmon losses were shifted upwards in energy due to the smaller unit cell volume in the titanium film, and an interface plasmon loss was also found.

Reaction with oxygen up to a maximum exposure of 3000 L occurred exclusively with the titanium component, the rate of reaction being about an order of magnitude slower than that observed by other workers on pure bulk titanium. The O/Ti atomic ratios measured at all stages of oxidation by AES, and the associated fine structure at each stage in the Ti LMM Auger spectra, were consistent with a process of oxidation first to TiO and then to Ti2O3, without the higher oxides appearing simultaneously. The maximum exposure used was insufficient for complete oxidation to TiO2. The ELS observations during oxygen exposure were in agreement with the proposed process.
Determination of lubricant thickness on magnetic recording heads using XPS
Authors: Leavitt P. K.
Published: May 2005

Many techniques are currently available for measuring lubricant thicknesses on magnetic recording disks. This paper describes a method for measuring lubricant thicknesses reproducibly and reliably on magnetic recording heads. Standard XPS disk lubricant thickness methods were used with appropriate modifications to account for substrate differences. Oxygen regions were ratioed instead of carbon, and R∞ for the heads was experimentally determined to be 0.37. Using these modifications, lubricant thicknesses were measured on heads from two different sources to try and explain file‐level operating differences.
A one‐film‐model ellipsometry program for the simultaneous calculation of protein film thickness and refractive index
Authors: Krisdhasima Viwat , McGuire Joseph , Sproull Robert
Published: May 2005

Heterogeneous protein films are not perfectly suited to ellipsometric analysis, and commercially available software often fails to yield meaningful optical properties for such films. Here, we describe a computer program uniquely suited for calculation of the thickness and refractive index of protein films. An important feature of the new program is an algorithm that allows a search for a solution in up to four directions.
Peculiarities of the Cu LVV Auger line in copper oxide cuprates and HTSC‐materials studied by x‐ray photoelectron and Auger electron spectroscopies
Authors: Akimov A. G. , Dementjev A. P. , Le Héricy J. , Kazansky L. P. , Khodan A. N. , Langeron J. P. , Melnikova N. A. , Rakhovsky V. I. , Vignes J. L.
Published: May 2005

Auger electron spectroscopy investigations of various copper compounds, including oxides, cuprates and high‐temperature superconducting (HTSC) YBaCuO‐type materials, show that the linewidth of the Cu LVV transition for these compounds increases with the oxygen‐to‐copper ratio. Correspondingly, for the same compounds, the intensity ratio of the satellite (Is) and main (Im) lines in the Cu 2p3/2 line measured from XPS spectra decreases. Taking into account the mechanisms of Auger electron and x‐ray photoelectron transitions, this correlation may be explained by an increase in the probability of electron transition from the O 2p to Cu 3d level in cuprates when compared with CuO. The peculiarities of Auger spectra found for YBa2Cu3O6.6–6.9 and for cuprates may be used to evaluate the quality of HTSC films by Auger microprobe.
Influence of the bombarding ion energy and surface composition on the ground‐state atom fraction in solids analysis using multiphoton resonance ionization
Authors: Pappas David L. , Hrubowchak David M. , Ervin Matthew H. , Winograd Nicholas
Published: May 2005

Multiphoton resonance ionization (MPRI) is used to probe the desorption characteristics of ion‐bombarded surfaces of Fe, In and Ni. The effects of primary ion kinetic energy and surface chemistry on the sensitivity and accuracy of MPRI detection are examined. The relative Ni*/Ni° and In2°/In° ratios are found to increase as the energy of the incident Ar+ ion is varied from 300 eV to 1000 eV. A reflecting time‐of‐flight mass spectrometer is employed to collect efficiently the photoions as well as secondary ions, permitting accurate determination of the ground‐state atom fraction and thereby completing a detailed fundamental analysis of the analytical capabilities of the MPRI approach. The ground‐state atom fractions are found to parallel changes in surface composition and represent 30–90% of the material desorbed from ion beam‐cleaned and air‐exposed Fe and In matrices. In contrast, the corresponding secondary ion fractions vary over several orders of magnitude and are difficult to correlate with surface chemistry.
Sputtered netural and molecular ion mass spectrometries in the characterization of multilayer samples
Authors: Moro L. , Canteri R. , Anderle M.
Published: May 2005

In this paper we report some results obtained in the analysis of multilayer samples employed in VLSI and ULSI microelectronic technology by means of hot electron gas SNMS (sputtered neutral mass spectrometry) and MCs+ SIMS.

A direct comparison of molecular ion SIMS with a post‐ionization technique pushed to its limits is presented.

A discussion in terms of dynamic range, optimum sensitivity and depth resolution is given.
Computer‐aided resolution enhancement for XPS imaging of an uncharged single chemical species
Authors: Grabherr M. G. , Ebel M. F. , Gurker N. , Svagera R. , Mantler M. , Ebel H.
Published: May 2005

Imaging XPS can be performed by an application of the double focusing properties of the hemispherical electron energy analyser. The x‐ray photoelectron spectra originating from an area of the specimen are depicted on a multichannel plate electron detector. An increasing size of this specimen area helps to reduce the total time for the generation of an XPS image. But, together with a reduction of the time of measurement, a loss of lateral resolution has to be expected. The present paper deals with the concept of computer‐aided compensation for the loss of resolution due to an increase of the observed specimen area. The principle of this concept is based on a deconvolution of the measured x‐ray photoelectron spectra.
Relation between the intensity of Auger lines and the cross‐relaxation energy in oxygen KLL lines of oxides
Authors: Brizuela Graciela , Castellani Norberto , Puentes Mirta
Published: May 2005

A calculation method is described and used to obtain the net ionic oxygen extra‐charge in oxides from the O KLL Auger intensities. The relation with the O KLL cross‐relaxation energies is also discussed.
First steps of the Ni–20 Cr alloy oxidation studied by Auger electron microprobe
Authors: Schmitt J. F. , Pacia N. , Pigeat P. , Weber B.
Published: May 2005

Polycrystalline Ni‐20 Cr alloy ribbons were studied after low‐pressure oxidation (3.3 × 10−4 Pa) at 750° C by scanning Auger microanalysis with argon ion sputter profiling. Only chromium oxide is formed under our experimental conditions and a 10% mechanical predeformation (uniaxial deformation) at ambient temperature is found to promote strongly the oxide formation on the alloy surface. In effect, it notably reduces the incubation period that precedes all our oxidations. However, the presented analysis reveals that the chromium oxide distribution is very heterogenous on predeformed oxidized samples at the beginning of the reaction.
Determination of the depth profiles of ion‐implanted impurities by electron probe x‐ray microanalysis
Authors: Alexeyev Andrey P.
Published: May 2005

The aim of this paper is to demonstrate the suitability of electron probe x‐ray microanalysis (EPMA) for nondestructive determination of the depth profiles of ion‐implanted impurities. The intensities of the characteristic x‐ray emission of impurity atoms (P and As) were measured (on a WDX spectrometer) on the implanted specimens and references (GaP and GaAs) at three values of primary electron energy EP. The range distribution of the implanted impurity as a first approximation is given by a Gaussian distribution. A two‐parameter fitting has been developed for the determination of Gaussian parameters RP and ΔRP of the profiles, which give a minimal difference between the experimental and calculated x‐ray intensities at different EP. The dose of the implanted impurity is a third parameter that can be obtained here. The results were compared with those of depth profiles from AES (for P) and SIMS (for As) and good agreement is observed. A new method for the determination of the depth distribution of x‐ray production for the characteristic x‐rays of impurity atoms is also presented.
Influence of surface preparation on oxidation of stainless steels at high temperature
Authors: Guillamet R. , Lenglet M. , Gazin L. , Hannoyer B. , Lopitaux J.
Published: May 2005

Fourier transform infrared specular reflectance spectra at variable incidence have been recorded in order to characterize the oxide layers formed on both mechanically polished and etched surfaces of stainless steels (AISI 304 and 316). Depending on the surface preparation, the major oxides are either Cr2O3 and MnCr2O4 for polished samples or α‐Fe2O3 and Fe3O4 for etched samples in the early stages of the oxidation in air at 900°C. Secondary ion mass spectrometry depth profiles confirm the schematic structure of oxide films (developed on polished surfaces during longer exposures) deduced from infrared reflectance study.
X‐ray photoelectron spectroscopic (XPS) study of DeNOx catalysts after exposure to slag tap furnace flue gas
Authors: Rademacher I. , Borgmann D. , Hopfengärtner G. , Wedler G. , Hums E. , Spitznagel G. W.
Published: May 2005

X‐ray photoelectron spectroscopy has been used to investigate the composition of both the surface of DeNOx catalysts (Ti:Mo:V = 92:6:2 and Ti:W:V = 85:10:5 at.%) and the material deposited from the flue gas. In spite of the charging of the surface in the spectrometer, it was possible to perform both qualitative and quantitative analysis. The deposits primarily contain Ca, Si, O, S, As, P and N. Oxidation numbers of Ca, Si, Ti, Mo, W, S and N were determined from chemical shifts in combination with line widths. There are, however, problems with the determination of the oxidation state of As owing to an influence of the exciting Al Kα radiation on the oxidation state. Nevertheless, As seems to exist both as As3+ and As5+.
Plasma processes and adhesive bonding of polytetrafluoroethylene
Authors: Kaplan S. L. , Lopata E. S. , Smith Jared
Published: May 2005

The virtues of chemical inertness and low surface energy which make polytetrafluoroethylene (PTFE) a valuable engineering polymer also account for the difficulty in achieving structural adhesive bonds. While plasma surface treatment has proven to be the most effective means of maximizing strength and permanence of adhesive bonds with the most inert of engineering polymers, a simple plasma treatment has proven elusive for PTFE. The following studies evaluate two very different plasma processes, activation and deposition, as a means to achieve reliable and high‐strength structural adhesive bonds. Sodium naphthalene‐etched PTFE is used as a control. Presented are ESCA data which support a theory that improvement is limited by a weakened boundary layer of the PTFE.