bluuebunny/crossref_metadata_2025 huggingface dataset:
A combined ISS and XPS investigation of passive film formation on Fe53Ni
Authors: Rossi A. , Calinski C. , Hoppe H.‐W. , Strehblow H.‐H.
Published: May 2005

A surface analytical study of the Fe53Ni alloy passivation process in alkaline solution was carried out by ISS (ion scattering spectroscopy) and XPS (x‐ray photoelectron spectroscopy).

The ISS depth profiles of the passive films formed in 1MNaOH show an iron‐enriched outer part of the film that is about three monolayers thick and stays on the surface independently of the polarization potential. This finding may be related to the outer hydroxide Fe/Ni film identified by XPS. The inner part of the quasi‐steady‐state passive film is nickel enriched and its thickness grows linearly with the potential. The results obtained by ISS satisfactorily agree with those obtained on the same samples by XPS, which demonstrates that ISS can be used profitably as a semiquantitative tool for the investigation of thin surface layers; in addition, it provides a higher depth resolution than XPS.
Influence of Cu, Ag, Ir and Pt on the work function and near‐surface electron density of Re mass spectrometer filaments
Authors: Baer D. R. , Hubbard C. W. , Gordon R. L.
Published: May 2005

The influence of metal overlayers on the properties of polycrystalline Re mass spectrometer filaments has been examined using contact potential difference (CPD) measurements of the work function, x‐ray photoelectron spectroscopy (XPS) measurements of overlayer binding energy (BE) and ultraviolet photoelectron spectroscopy (UPS) measurements of electron energy distribution curves (EDCs). Work function data for CuRe, AgRe and IrRe are compared to earlier results for AuRe, PdRe and PtRe as part of the effort to understand the influence of surface additions to the work functions of ionization sources. The changes in work function owing to the addition of a metal overlayer do not always follow predictions of bulk electron transfer, such as the Miedema electronegativity. However, the observed changes in work function are consistent with a simple initial‐state understanding of the XPS core‐level data involving charge flow toward and away from the surface. The XPS binding energy shifts are consistent with shifts observed in the valence bands for Cu and Ag on Re.
Estimation of the uncertainties associated with XPS peak intensity determination
Authors: Evans Stephen
Published: May 2005

Formulae are presented for estimation of the statistical uncertainties (standard deviations) associated with the peak heights and integrated intensities (areas) required for elemental quantification in XPS in situations where peak overlap is not significant. The situation arising when curve‐resolution procedures are used to separate discrete XPS signals for quantification is discussed, and a simple, rapid, but approximate procedure to estimate standard deviations for both the parameters characterizing the fit and the overall component intensities is developed. Both minimum‐χ2 and unweighted least‐squares procedures are considered. Some difficulties in relation to background subtraction and the inevitable presence of systematic errors in most XPS curve‐fitting procedures are identified and discussed.
Modified procedure of quantitative analysis by AES
Authors: Mrozek P. , Lesiak B. , Jablonski A.
Published: May 2005

Much controversy in the literature is associated with the definitons of terms describing electron transport in solids, i.e. the inelastic mean free path, the attenuation length, the escape depth, etc. This may cause some confusion in determining the corresponding correcting factors for calculations of quantitative AES. There are indications that the proper parameter for the correcting procedure is the inelastic mean free path (IMFP). None the less, difficulties may be encountered in estimating the values of the IMFP for studied samples, particularly for binary or multicomponent systems.

A novel procedure of quantitative analysis is proposed in which knowledge of the IMFP is no longer necessary. Actually, the correction procedure normally used requires the ratio of the IMFP for the sample and the standard. One can take advantage of the fact that the IMFP is related to the absolute elastic peak intensity. In that case, determination of the ratio of elastic peak intensities for the sample and the standard makes possible calculation of the ratio of the IMFP. Inasmuch as the measurements of the absolute elastic peak intensities offer considerable experimental difficulties, the determination of the ratio of intensities is relatively easy to perform. Thus, recording the ratio of elastic peak intensities, in addition to the ratio of Auger electron intensities, provides complete information for the correction procedure of quantitative analysis. Such a procedure has two important advantages: the ratio of the IMFP is determined for the studied samples instead of taking these values from the literature, and the actual concentration dependence of the IMFP is accounted for. The calibration plots facilitate recalculation of the ratio of elastic peak intensities to the ratio of the IMFP. Somewhat lengthy calculations are necessary to determine such a plot; however, they are made only once for a given alloy. Application of the proposed method of quantitative analysis is illustrated by using the AuPd alloys.
UPS and XPS study of the polymer/metal interface of poly(2‐methyl‐2‐propenenitrile) electropolymerized on an oxidized nickel surface cathode
Authors: Deniau G. , Viel P. , Lécayon G. , Delhalle J.
Published: May 2005

Mechanisms of formation and structure of the interface between an oxidized nickel surface and poly(2‐methyl‐2‐propenenitrile) obtained by electropolymerization under cathodic polarization are studied by UPS and XPS spectroscopies. The results suggest that a direct interaction takes place between the monomer molecules and surface metallic sites freed by reduction of the metal oxides. The interface between the metal and the resulting polymer is characterized by the existence of chemical bonds of the carbon–nickel type.
Background removal in x‐ray photoelectron spectroscopy
Authors: Tokutaka Heizo , Ishihara Naganori , Nishimori Katsumi , Kishida Satoru , Isomoto Kazuhiro
Published: May 2005

Background removal from x‐ray photoelectron spectra (XPS) was evaluated using the Shirley method and the Tougaard method. The effect of background removal over a range of kinetic energy was evaluated, and the Tougaard method was found to be effective over a wide energy range. In this paper we report a modification of the Tougaard method that is shown to provide satisfactory background removal from a wide range of XPS data.
Studies of surface composition, structure and oxygen adsorption of Ni3Al(110) by Li+ and He+ ion scattering
Authors: Shen Y. G. , O'Connor D. J. , MacDonald R. J.
Published: May 2005

The surface composition, structure and initial stages of oxygen adsorption of Ni3Al(110) have been investigated by ISS. The surface composition of the Ni3Al(110) surface was determined by Li+ and He+ ion scattering using selected scattering geometries. These results consistently show a surface composition of 50% Ni‐50% Al in the outermost layer with some small percentage of Ni enhancement (perhaps 1–2%), while the second layer is basically Ni. The surface structure has been probed by measuring the intensity of Li+ ion scattering as a function of incident angle along the [001], [112], [111], [332] and [110] azimuthal directions. The interpretation of experimental data is based on the calibrated shadow cone and chain model simulations. The results show that there is no displacement of first‐layer Al relative to first‐layer Ni, but there is a contraction in the first‐to‐second layer spacing of 0.11 ± 0.08 Å. The adsorption of oxygen at low exposure (∼8L) and pressures in the range 2 × 10−8−1 × 10−6 mbar at a temperature of 700°C shows the disappearance of the Ni ISS signal, and the results suggest the formation of a monolayer of an AlOx overlayer. Using a model similar to that previously studied for the formation of AlOx islands on the Ni3Al(001) surface, this oxide overlayer has been shown to be AlOx islands with no influence on remaining areas on the crystal. The mechanism for apparent interchange of the Al atoms to the surface to replace the Ni atoms is also discussed.
Characterization of hydroxylated oxide film on iron surfaces and its acid–base properties using XPS
Authors: Kurbatov G. , Darque‐Ceretti E. , Aucouturier M.
Published: May 2005

X‐ray photoelectron spectroscopy was used to characterize the hydroxylated oxide film on iron surfaces. The composition of the films and its transformations for eighteen specimens prepared by ex situ techniques and simulating various conditions of hydroxylated oxide layer formation were examined. A model of hydroxylated oxide multilayer film formation on iron was proposed. Quantitative analysis procedures of its composition and hydroxyl group population determination were given.

Anion and cation exchange experiments at the specimen surfaces in solutions at different values of pH followed by x‐ray photoelectron analysis of the surface compositions were employed for the estimation of acid–base properties.
Effects of electrochemical and plasma treatments on carbon fibre surfaces
Authors: Jones Carol
Published: May 2005

This paper summarizes the chemical changes induced on carbon fibre surfaces (examined by X‐ray photoelectron spectroscopy, XPS) by a variety of electrochemical treatment in aqueous electrolytes together with the improvements in fibre/resin bonding in the corresponding composite materials. It was found that there was no correlation between the amount of chemical functionality introduced onto the fibre surface and the fibre/resin bond strength, i.e. chemical bonding does not play a major role in fibre resin adhesion. This does not rule out the possibility of chemical bonding between the fibre and resin—it simply implies that it is not the governing factor. It is suggested that the immediate surface concentration of chemical groups is too low to make a significant contribution.

To tailor interfacial properties it would be desirable to promote chemical bonding between fibre and matrix. The use of a specially designed plasma treatment cell has led to an increase in the surface concentration of chemical groups (COH, hydroxyl) that have the potential to react chemically with the resin. By exploiting grazing angle data taken from XPS analysis, it is shown that changes in the chemical nature of the fibres only occurs in the outermost layers, whereas the electrochemical reaction proceeds well into the fibre sublayers. Selective introduction of nitrogen‐containing functionality (such as amines, NH2) has been achieved. The reactivity towards a particular plasma is shown to be largely dependent on the structure of the fibre surface. The number of C/N groups produced on higher modulus fibres was undesirably low. Their concentration was increased by biasing the fibres to a negative potential (10–30 V) during plasma exposure.
Contamination of surfaces: Origin, detection and effect on adhesion
Authors: Davis Guy D.
Published: May 2005

Surface contamination is one of the most insidious factors affecting adhesive bond performance and, hence, reliability of bonded structures. Sources of contamination are widespread and include primary materials, secondary materials, equipment, human operators, adjacent processes and the atmosphere. A successful approach to solving contamination problems involves the identification of the contamination and its source, establishment of the level of contamination that degrades the given bond, development of a plan to correct the problem and prevent contamination from occurring again, and subsequent verification of adequate substrate cleanlines prior to bonding. This generic approach is discussed and examples are cited to illustrate its use.
Polymer–metal interface formation and film growth on plasma and ion‐treated polymer surfaces
Authors: Nowak S. , Collaud M. , Dietler G. , Schmutz P. , Schlapbach L.
Published: May 2005

A study of polymer‐metal interface formation after plasma treatment and low‐energy ion bombardment is presented. In situ surface analysis by XPS lead to well‐defined surface compositions. Different types of bonding of an evaporated metal overlayer with the polymer surface compositions. Different types of bonding of an evaporated metal overlayer with the polymer surface are observed. Depending on the surface treatment, an island growht mode of the metal with different degrees of coverage is observed. Measurement with an atomic force microscope show that the surface treatment also leads to increased surface forces.
The effect of energy‐dependent detector efficiency in electron spectroscopic methods: XPS, AES and DCEMS
Authors: Kajcsos Zs. , Meisel W. , Griesbach P. , Gütlich P.
Published: May 2005

Systematic studies were performed to investigate the distorting effect of the electron energy dependence of the channeltron detector efficiency on the shape of data distributions in electron spectroscopy. In agreement with earlier results for electron energies up to 3 keV, it was found that a virtually energy‐independent shape of the electron distribution might be achieved even in a very broad range of electgron energies (up to 15 keV) by appropriate selection of the operational high voltage of a channeltron. However, the efficieny of channeltrons was also found to depend on count rates, indicating one of the principal difficulties in comparing distribution recorded under different experimental conditions.
Interlaboratory comparison of the depth resolution in sputter depth profiling of Ni/Cr multilayers with and without sample rotation using AES, XPS, and SIMS
Authors: Hofmann S. , Zalar A. , Cirlin E.‐H. , Vajo J. J. , Mathieu H. J. , Panjan P.
Published: May 2005

In order to provide a consistent judgment on the capabilities and limitations of the sample rotation approach to depth profiling, a round robin (interlaboratory comparison) was organized between four laboratories on identical samples using AES, XPS and SIMS. The sample consisted of an Ni/Cr multilayer with a total of 16 alternating Ni and Cr layers with a singly layer thickness of 30 nm. Sputter profiling was performed with a rastered beam of 3 keV Ar+ ions at an incidence angle of 45° to the surface normal, with and without sample rotation. Test runs were additionally performed with BCR standard samples of 30 nm thick Ta2O5 layers on Ta. For sample rotation, depth profiles of the Ni/Cr multilayer by AES and SIMS show a marked improvement in depth resolution of about a factor of two for lower sputter depth (30 nm) and four to five for greater sputter depth (450 nm). The depth resolution deteriorates with depth for stationary samples, but is found to be independent of depth when using sample rotation. For XPS, the depth resolution improvement for sample rotation is less pronounced. Agreement between the different laboratories and techniques is excellent and clearly demonstrates the capabilities of sample rotation in depth profiling studies.
Refinement of magnesium and aluminium Kα x‐ray source functions
Authors: Klauber C.
Published: May 2005

The magnesium and aluminium Kα x‐ray line structures, for application to x‐ray photoelectron spectroscopy peak analysis, have been re‐examined for the Kα1, Kα2, Kα′, Kα3, Kα3′, Kα4, Kα5 and Kα6 components. Commonly employed literature source functions are compared with each other and to the refined functions in this work. In terms of both useful removal of x‐ray satellite structure and general x‐ray broadening effects, a detailed description of the complete minor satellite structure is less important than an accurate representation of the main lines and the six most intense satellites, including the generally ignored Kα3′. Some of the inaccuracies have arisen from the inappropriate adoption of x‐ray emission data without the removal of spectrometer broadening. Other errors in determining the source functions come from the excessive smoothing employed in the noise reduction necessary for deconvoluted spectra. This obliterates localized oscillations, which can actually be removed by fine‐tuning component parameters without resorting to increased smoothing or filtering. It is demonstrated that reductions in spectral component width of up to 50% are possible.
Elastic scattering corrections in AES and XPS: I. Two rapid Monte Carlo methods for calculating the depth distribution function
Authors: Cumpson Peter J.
Published: May 2005

We present improvements to the Monte Carlo methods used to calculate emission depth distribution functions (DDFs), emission function decay lengths (EFDLs) and attenuation lengths in quantitative XPS and AES. These reduce the time required to reach any desired level of accuracy by a factor of ∼500, so that even a personal computer can produce accurate results in 2 or 3 min. These rapid results are due to the new technique of averaging over an ensemble of possible inelastic events for each feasible set of elastic scatterings in the Monte Carlo simulation, closely related to methods that have been used successfuly in nuclear physics for many years. No new approximations are required. The results are compared with exact analytical solutions for simple special cases; agreement is excellent.
Ion scattering and electron spectroscopic study of the surface coverage of V/Al2O3 catalysts
Authors: Eberhardt Mary A. , Houalla Marwan , Hercules David M.
Published: May 2005

Ion scattering spectroscopy (ISS) and x‐ray photoelectron spectroscopy (XPS, ESCA) were used to study the dispersion of the vanadium phase and the coverage of Al2O3 by vanadium. A series of V/Al2O3 catalysts was prepared by equilibrium adsorption with vanadium loadings varying from 1.9 to 6.7 wt.% V. By monitoring the ISS Al/O intensity ratio the surface coverage of the catalysts was determined. The surface coverage increases from 15 to 33% with increasing the loading from 1.9 to 3.5 wt.% V. The results are consistent with a model of a uniform monolayer vanadium phase. For higher vanadium loadings the surface coverage appears to level off, suggesting the formation of a multilayer vanadium phase.
Formalism and parameters for quantitative surface analysis by Auger electron spectroscopy and x‐ray photoelectron spectroscopy
Authors: Jablonski A. , Powell C. J.
Published: May 2005

It has been realized during the last 5 years that quantitative surface analyses by Auger electron spectroscopy (AES) and x‐ray photoelectron spectroscopy (XPS) can be greatly complicated by the effects of elastic electron scattering. These effects had previously been largely ignored. We review here the effects of elastic scattering in the formalism of quantitative surface analysis by AES and XPS and discuss the various definitions of terms (inelastic mean free path, attenuation length and escape depth) that have been used to describe inelastic scattering and the surface sensitivities of various electron spectroscopies. We show how a realistic theoretical model of electron transport that includes elastic electron scattering can be related, for some analytical situations, to the common simple formalism of AES and XPS in which elastic scattering is neglected. We consider specifically measurements of overlayer thickness, determination of surface composition for a homogeneous surface region and estimation of the average depth of analysis and we indicate which parameter describing inelastic scattering can be utilized in the simple formalism for these applications. Information is given on sources of data for the inelastic mean free path and the attenuation length. Finally, we point out that the definitions of some terms are undergoing revision as a result of recent scientific developments and to avoid inconsistencies with established usage in other fields.
Fundamental parameters in quantitative depth profiling and bulk analysis with glow discharge spectrometry
Authors: Payling Richard , Jones D. G.
Published: May 2005

By re‐examining the roles played by the fundamental parameters in glow discharge spectrometry (GDS), a simpler approach to quantitative GDS is obtained. A new method is presented for separating the effects of the lamp parameters on emission yield, by varying the matrix. It is shown in the normal working ranges that emission yield depends on lamp pressure only and not on lamp voltage and current as previously thought. The theory is applied to depth profiles from three very different commercial metallic‐coated steels and good agreement is obtained with SEM–energy‐dispersive spectroscopy (EDS) line scans of the coatings. The implications of using constant pressure for bulk analysis are also described. The ability of GDS to measure sputtering rates simultaneously with concentration is explored and good agreement is obtained for zinc–iron alloys with calculated sputtering rates based on surface concentrations.
Imaging microanalysis of ceramic materials with a scanning ion microprobe
Authors: Soni K. K. , Chabala J. M. , Mogilevsky R. , Levi‐Setti R. , Zhang K. , Wolbach W. S. , Bryan S. R.
Published: May 2005

This article discusses the application of a scanning ion microprobe coupled with secondary ion mass spectrometry (SIMS) in the microanalytical characterization of ceramic materials. The high spatial resolution afforded by the microprobe mode, in conjunction with the analytical sensitivity of SIMS, make this technique ideally suited to explore the microchemistry of ceramics, which have complex microstructures and contain several trace and light elements. Two case studies of interface analysis are presented: YBa2Cu3O7‐x superconductors and sintered silicon carbide. Sodium and chlorine impurities were found to segregate to the grain boundaries of melt‐grown YBa2Cu3O7‐x, accompanied by oxygen deficiency. In SiC sintered with Al2O3, Al was present along the grain boundaries in elemental from and at triple‐grain junctions as Al oxide second phases.
In situ ToF‐SIMS/XPS investigation of nitrogen plasma‐modified polystyrene surfaces
Authors: Petrat F. M. , Wolany D. , Schwede B. C. , Wiedmann L. , Benninghoven A.
Published: May 2005

Plasma modification of polymer surfaces is a well‐established technique for many technological applications. The control of the surface composition after plasma treatment requires in situ characterization by adequate surface analytical techniques. As an example, we investigated polystyrene modified by a microwave (2.45 GHz) nitrogen plasma by using an on‐line combination of time‐of‐flight secondary ion mass spectrometry and monochromatized photoelectron spectroscopy.

Plasma treatment without subsequent air contact leads to the incorporation of nitrogen, the formation of amine, imine and nitrile bonds as evidenced by the C 1s and N 1s photoelectron lines, and the appearance of predominant CxNy clusters in the negative secondary ion spectra. These changes seem to be stable against organic solvents. A particular feature is the formation of a graphite‐like C 1s state after prolonged plasma treatment. The polystyrene surface after plasma treatment is very reactive, particularly the graphite‐like carbon state. Exposure to the atmosphere leads to the disappearance of this state, to considerable uptake of oxygen and to the formation of carbon‐nitrogen‐oxygen bonds, as evidenced by the CNO− secondary ion cluster and the amide binding state in the C 1s line.
Simple method of depth profiling (stratifying) contamination layers, illustrated by studies on stainless steel
Authors: Seah M. P. , Qiu J. H. , Cumpson P. J. , Castle J. E.
Published: May 2005

Stainless‐steel artefacts are used as reference masses for the calibration of balances and instruments involving force. The surfaces of these masses react with the environment, leading to changes in the chemistry of the steel surface, accretion of surface contamination layers and a dynamic absorption of moisture in those contamination layers. In order to understand these layers, to stabilize or correct for the concomitant mass changes, it is important to define what chemical states are developing and their stratification at the surface. Four chemical states are identified in the oxygen XPS peak and four in the carbon peak. In the project a very large number of samples are studied and so a rapid, simple stratifying method has been developed requiring measurements at only two angles of emission. The method, which involves a simple ratio of the peak intensities either after separation of the states or by using the peak envelope, or just by ratioing the whole spectra at the two angles enables the stratification and other parameters to be readily determined for all eight peaks.
18O tracer study of the oxidation of zircaloy‐4 in steam
Authors: Matsuda Y. , Anada H. , Bishop H. E.
Published: May 2005

The corrosion resistance of Zircaloy‐4, used as fuel cladding in pressurized water reactors, in steam at 400°C is related to the annealing temperature used in fabrication. This change in corrosion behaviour appears to be related to the size and composition of intermetallic compound precipitates, which vary with annealing temperature.

A SIMS study has been undertaken to clarify the mechanisms responsible for these variations in the initial stages of corrosion of Zircaloy‐4. A set of samples subjected to different annealing temperatures have been oxidized, initially in normal steam and subsequently in steam enriched in H218O. Corrosion mechanisms have been followed using depth profiling in a Cameca IMS 3F microscope together with three‐dimensional depth profiles and imaging of taper sections using a gallium microprobe (VG Scientific).

Iron and chromium, present in intermetallics in the alloy, remain localized within the oxide scale. The size and frequency of these local concentrations of iron and chromium reflect the distribution of these elements in the alloy. There is, however, some diffusion of these elements into the surrounding oxide, the iron diffusion being greater than that for chromium. The18O tracer studies indicate that grain boundary transport of oxygen dominates the initial oxide growth process for Zircaloy‐4.
Application of tougaard background subtraction to XPS spectra of passivated Fe–17 Cr
Authors: Norgren B. S. , Somers M. A. J. , De Wit J. H. W.
Published: May 2005

In order to examine the spectra of films formed during the polarization of an Fe–17 Cr alloy in 0.5 M sulphuric acid, it is necessary to separate the overlapping spectral components of the film and substrate. The procedure for peak separation and background subtraction as proposed by Hansen and Tougaard was followed and is described in detail for the present case. On applying the procedure it was observed that the results obtained are sensitive to the value used for the film thickness in calculating the contribution from the substrate to the overall spectrum. Thus, the film thickness can be regarded as an outcome of the procedure. The elastic XPS spectrum of the film remaining after peak separation and background subtraction was compared to that obtained after subtraction of a Shirley background followed by curve fitting of the substrate contribution.
Observation of the action of penicillin on bacillus subtilis using atomic force microscopy: Technique for the preparation of bacteria
Authors: Kasas S. , Fellay B. , Cargnello R.
Published: May 2005

Atomic force microscopy (AFM) is a very convenient means of studying hard and flat samples with atomic resolution. Biological objects, usually soft and rough, are sometimes difficult to image using this technique. Bacteria, which are too small to be observed with good resolution using the optical microscope, are hard enough to be observed with an atomic force microscope at a level of magnification similar to that obtained with the electron microscope. These microorganisms can be prepared for AFM imaging using very rapid and simple techniques. We discuss here different preparation methods and substrates that can be used for the preparation of bacterial samples for observation with AFM. We also show images of different species of bacteria, such as Escherichia coli, and Bacillus subtilis, taken with the atomic force microscope in constant force and constant height modes, as well as images demonstrating the action of penicillin on B. subtilis.
Use of parallel imaging XPS to perform rapid analysis of polymer surfaces with spatial resolution >5 μm
Authors: Forsyth N. M. , Coxon P.
Published: May 2005

X‐ray photoelectron spectroscopy (XPS or ESCA) is one of the most common surface analytical techniques available. It has proved over many years to be invaluable in the analysis of elemental and chemical species on surfaces. The recent developments of this technique towards spatially resolved XPS information has made it possible to use XPS for analysis of very small features on insulating materials such as polymer surfaces, on which other high spatial resolution techniques such as Auger electron spectroscopy (AES) suffer difficulties generated by, for example severe sample charging effects.

The new VG ESCALAB 220iXL from VG Scientific (Fisons Instruments) uses parallel imaging together with a magnetic objective lens to provide chemical images of better than 5 μm spatial resolution in just a few minutes. Subsequent point analysis using selected small‐area XPS can be performed on any feature in the images down to 7 μm resolution. In combination with this unique parallel imaging facility, a new high‐intensity x‐ray monochromator source makes fast chemical state imaging at high spatial resolution relatively routine. Several examples of the analysis of polymer surfaces wil be shown, including chemical state imaging of the C 1s, CC, and CO bonding states from 15 μm features.
Activities of ISO technical committee 201 on surface chemical analysis
Authors: Powell C. J. , Shimizu R.
Published: May 2005

A status report is given on activities of ISO Technical Committee 201 (ISO/TC 201) on Surface Chemical Analysis. The committee has seven subcommittees which met for the first time in 1993. Information is given on the working groups that have been established for specific purposes. We show national participation in ISO/TC 201 and its subcommittees, and we identify the chairmen and secretariats of the subcommittees and the conveners of the working groups.
Ion sputter rates and yields for iron‐, chromium‐ and aluminium oxide layers
Authors: Viefhaus H. , Hennesen K. , Lucas M. , Müller‐Lorenz E. M. , Grabke H. J.
Published: May 2005

Layers of the oxides FeO, Fe3O4, Fe2O3, Cr2O3 and Al2O3 were prepared by evaporation of the corresponding metal layers onto a preoxidized Si substrate and oxidation at elevated temperature. The oxidation was conducted under thermodynamically well‐defined conditions so that the pure oxide phases noted were obtained. The oxide layer thickness was calculated from the thickness of the initial metal film, which was determined by chemical analysis and from the frequency change of a quartz crystal upon evaporaton. Auger electron spectroscopy depth profiles of the oxide layers were measured during Ar+ sputtering, and the sputter time necessary to reach the interface oxide/substrate was determined. The determination of this sputter time was not very exact, because the transition from oxide to substrate in the profile was rather gradual, owing to the roughness and crystalline character of the oxide layers that causes inhomogeneous sputtering. However, from the sputter time, oxide thickness and ion beam current, the sputter rates were obtained for the oxides noted (in nm μA−1 cm−2 min−1) and were compared to the sputter rate of amorphous Ta2O5, which is generally used as the sputter reference standard. Considerable differences were found. The results will lead to more reliable determinations of oxide scale thicknesses by sputtering.
Small‐area XPS investigation on ion‐induced chemical modifications during depth‐profiling of an AlxGa1−xas/gaas structure
Authors: Padeletti G. , Ingo G. M.
Published: May 2005

Depth profiling by argon ion sputtering was carried out on an Al0.3Ga0.7As/GaAs layered structure, using different ion‐beam energies (up to 5 keV) and keeping constant the ion current density. When the steady state condition was reached in the ternary layer, in order to investigate the ion‐induced chemical modifications, angle resolved small‐area x‐ray photoelectron spectroscopy (SA‐XPS) investigations were carried out on the bottom of the crater resulting from the ion‐beam erosion. In order to study the different regions of the damaged layer, attention was focused on the As 3d, Ga 3d and Al 2p signals as well as on the As 2p3/2 and Ga 2p3/2 peaks, which are spread over an energy range about 1000 eV wide and therefore photoemitted from different depths. The results show the different ion‐induced effects on the chemical composition of the Al0.3Ga0.7As layer, such as arsenic preferential sputtering, aluminium Gibbsian segregation and further, the formation of elemental species, as a function of the Ar+ energy.
A spectroscopic analysis of plasma polymers prepared from a series of vinyl sulphones
Authors: Ward Alison J. , Short Robert D.
Published: May 2005

Plasma polymers (PPs) have been prepared from methyl vinyl sulphone (MVS), ethyl vinyl sulphone (EVS) and vinyl sulphone (VS). The ratio of radio frequency (r.f.) power (W) to flow rate of monomer (F) or W/F is an important parameter in plasma polymerization. PPs prepared at low and high W/F were analysed by x‐ray photoelectron spectroscopy (XPS), time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) and grazing angle infra‐red (GAIR) spectroscopy.

XPS revealed that significant quantities of the sulphone group had been retained from the monomer. The greatest retention was observed in the PPs that had been prepared at low W/F, where the majority of the sulphur was present as RSO2R/H. The remaining sulphur being in RSOR/H and RSR/H environments. This trend was reversed in the PPs prepared at high W/F.

The negative secondary ion mass (SIM) spectra of PPs prepared at high and low W/F were examined and structures proposed for the prominent ions. The relative intensities of these ions were different for the PPs prepared at high and low W/F. This showed that there had been a greater retention of structures from the monomer in the PPs that were prepared at low W/F.

The GAIR spectroscopy confirms the presence of sulphone groups throughout the PP film. It also shows that carbonyl groups are present which cannot be confirmed by XPS alone.
X‐ray photoelectron spectroscopy and scanning electron microscopy of β‐FeSi2 films grown by Ion Beam assisted deposition
Authors: Armelao L. , Terrasi A. , Boaro M. , Ravesi S. , Granozzi G.
Published: May 2005

This paper reports the investigation of polycrystalline β‐FeSi2 films grown by Ion Beam Assisted Deposition (IBAD), performed by using a broad Ar+ beam bombarding (001) Si substrates during the evaporation of Fe atoms. Several energies (200–650 eV) and current densities (10–70 μA cm−2) have been used for the Ar+ beam, keeping the Fe evaporation rate at about 0.08 nms−1. The formation of the silicide was achieved by in situ thermal annealing at T = 600 °C, performed during or after the deposition process. Rutherford Backscattering Spectroscopy (RBS), Scanning Electron Microscopy (SEM) and X‐Ray Photoelectron Spectroscopy (XPS) have been used to study the stoichiometry, the morphology and the chemical status of several samples obtained using different ion beam parameters. Strong morphological improvements, such as smoothing and pinhole closing, are observed for the IBAD films grown during thermal annealing. The XPS depth profiling technique has been used to investigate the morphology of the silicide/Si interface.
Ion bombardment induced modification of polyvinyltrimethylsilane studied by XPS
Authors: Tóth A. , Bertóti I. , Khotimsky V. S.
Published: May 2005

Polyvinyltrimethylsilane films were bombarded by 1 keV and 5 keV Ar+ and N2+ ions up to fluences of about 1017 ions cm−2. XPS studies showed the actual surface composition and the chemical bonding to be dependent on the nature of the projectile applied, the ion energy, the fluence, the presence or absence of low energy flooding electrons, and the time elapsed between the ion beam treatment steps. Exposure of the ion beam treated samples to ambient air resulted in a strong uptake of oxygen, the attack of which took place predominantly on Si and to a lesser extent on C.
Bulk‐to‐surface diffusion measurements in a (111)Cu(0.1 at.%)Sn single crystal using a linear programmed heating method
Authors: Viljoen E. C. , du Plessis J.
Published: May 2005

Using the recently proposed method of linear heating, the diffusion parameters (D0 and E) were determined for a Cu(0.1 at.%)Sn single crystal. In this method, the sample temperature is increased linearly with time and the surface concentration is measured by Auger electron spectroscopy as a function of temperature (or time). The main advantage of this method is that the diffusion parameters may be obtained from a single run. Four runs were made at 0.1, 0.25, 0.5 and 1.0 °C s−1 and the average diffusion parameters (D0 = 9.2 × 10−4m2 s−1 and E = 189 kJ mol−1) agree well with other published values.
Quantitative depth profile analysis by EPMA combined with Monte‐Carlo simulation
Authors: Ammann Norbert , Karduck Peter
Published: May 2005

Calibrated x‐ray intensities of arsenic and gallium, implanted with various ion‐energies and doses into silicon, were measured over a wide range of electron‐beam energies and angles of incidence. For the first time Monte‐Carlo (MC) simulation was applied to evaluate the EPMA‐data with respect to depth‐profiles parameters, particularly at non‐normal electron incidence. Accurate agreement between MC‐simulated and measured k‐ratios was obtained in the whole range of excitation conditions applied. The resulting range parameters determined from the EPMA data agree closely with those obtained by other authors from RBS or NAA but like these they show systematic deviations from theoretical predictions. Actual measurements on samples implanted with 1014 ions cm−2 clearly prove the limits of detectability for As and Ga in Si to be below this number. Similar sensitivity was found for elements with atomic numbers Z > 10 but for light elements (Z ⩽ 10) the limit of detectability is increased by about one order of magnitude. Provided the concentrations are appropriate, EPMA combined with MC‐simulation is a promising technique for the accurate quantitative, non‐destructive, and spacially resolved analysis of depth‐profiles.
Factor analysis, a useful tool for solving analytical problems in AES and XPS: A study of the performances and limitations of the indicator function
Authors: Arranz A. , Palacio C.
Published: May 2005

Computer simulations have been used in order to investigate an objective procedure to determine the number of principal factors when factor analysis is used for solving analytical problems in AES and XPS. The indicator (IND) function has been used in the investigation. The simulated results show that the IND function could be used for detecting and solving sampling misalignment problems. Furthermore, the S/N ratio, the severe overlap of spectra and the relative importance of the various factors involved can limit the sensitivity of the IND function to determine the correct number of principal factors.
Ambient oxygen effect in Ga+ FIB‐SIMS
Authors: Sakamoto Tetsuo , Tomiyasu Bunbunoshin , Owari Masanori , Nihei Yoshimasa
Published: May 2005

Enhancement of Al positive secondary ion emission by ambient oxygen was investigated by Ga+ focused ion beam (FIB) SIMS instrument at various combinations of oxygen partial pressure and scanning area of FIB. A model calculation was made which assumes that the amount of enhancement of single‐charged positive secondary ion emission is directly proportional to the oxygen concentration in the mixing layer. The observed amount of enhancement showed a characteristic dependence both on the oxygen dose and the beam scanning area. The model calculation well reproduced most of the features quantitatively.
Charging and mixing effects during the XPS analysis of mixtures of oxides
Authors: Fernández A. , Espinós J. P. , Leinen D. , González‐Elipe A. R. , Sanz J. M.
Published: May 2005

In this article we present an XPS analysis of mixtures of Al2O3 and TiO2 powders of different relative size in order to study differential charging effects. To illustrate some of the possible situations we have studied the behaviour of three different samples: (1) very large (microns) and porous particles of Al2O3 supporting TiO2 particles of relatively small size (300 Å); (2) Al2O3 and TiO2 particles of similar size (300 Å); and (3) very small particles (20–30 Å) of TiO2 dispersed in Al2O3 particles of 300 Å. The observed effects are then analysed by using Auger parameters and relative binding energies and discussed in terms of the different morphologies of the samples, as determined by TEM. The influence on charging of an electron flood gun and of Ar+ sputtering is also presented. In addition, ion‐induced mixing effects have been clearly observed in the case of very small particles of TiO2 dispersed on alumina.
Database of relativistic elastic scattering cross‐sections for calculations of photoelectron and Auger electron transport
Authors: Jablonski A. , Tougaard S.
Published: May 2005

Quantitative applications of electron spectroscopies, AES and XPS, should be based on theoretical models describing realistically the electron transport in solids. Detailed knowledge of elastic scattering cross‐sections due to the elements constituting a given solid is necessary in such calculations. To some extent, such data are available in the literature, but a complete data set in the form of a computer controlled database is not available. An extensive software packet is described in the present article for providing relativistic elastic scattering cross‐sections for elements with atomic numbers up to 96. The energy range for each element varies from 50 to 10000 eV in steps of 1 eV. The software packet has the following options: (1) visualization of the differential elastic scattering cross‐sections in different coordinate systems; (2) creation of files containing the elastic scattering cross‐sections for specified elements, energies, and coordinates; (3) creation of random number generators providing the polar scattering angles to be used in Monte‐Carlo simulation of the transport of electrons in solids; and (4) testing the performance of the created random number generators.
Deposition of CeO2 on Si(111) studied by LEED, AES, XPS and RBS
Authors: Guillaume C. E. , Vermeersch M. , Sporken R. , Verbist J. J. , Mathot S. , Demortier G.
Published: May 2005

The deposition of CeO2 on Si(111) has been studied by low energy electron diffraction (LEED), Auger electron spectroscopy (AES), x‐ray photoelectron spectroscopy (XPS) and Rutherford backscattering spectroscopy (RBS). LEED shows the CeO2 layer to grow in the (111) orientation. The formation of a silicon oxide layer at the interface is observed. The thickness of this oxide layer is found to vary between about 1 and 8 nm, depending on the thickness of the CeO2 layer. A model for the growth of CeO2 and for the formation of the silicon oxide layer at the interface is proposed.
High‐resolution electron‐energy‐loss spectroscopy of hydroxyl groups at the surface of bulk insulating oxides
Authors: Coustet Valérie , Jupille Jacques
Published: May 2005

The capability of high‐resolution electron‐energy‐loss spectroscopy to study adsorbates at the surface of bulk insulating oxides has been applied to the cases of OH/MgO(100) and OH/α‐Al2O3(0001). On MgO(100), two types of OH have been identified, either bonded to surface Mg ions (A type) or due to proton adsorption on surface oxygen ions (B type). Dense OH adlayers on MgO(100) (5‐coordinate Mg) have been seen to correspond to νOH(A) = 3690 cm−1 (νOH > 3700 cm−1 being suggested to be related to defects and/or low coverages). On α‐Al2O3(0001), a sharp stretching band νOH has been recorded at 3720 cm−1 and assigned to OH bonded (or bridge‐bonded) to Al in octahedral position.
Surface reactions at the controlled structure of SrTiO3(001)
Authors: Kudo Masahiro , Hikita Tokihisa , Hanada Takashi , Sekine Rika , Kawai Maki
Published: May 2005

The surface structures and reactions on the single domained surfaces of SrTiO3(001) are investigated using MBE and various surface characterization techniques, such as RHEED, UPS and XPS. The selective formation of the two types of SrTiO3(001) surfaces, the TiO2 terminated and the SrO terminated surfaces, was carried out by Bi deposition/desorption cleaning method and Sr deposition, followed by oxidation in the NO2 atmosphere. It is shown that both surfaces have increased atomic distance between the first and the second layers, and the outward displacement of the first layer oxygen atoms. Surface reaction of H2O was investigated in relation to the Ti3+ defects formed by Ar+ bombardment, with the aim of obtaining knowledge on the reaction between surface functional groups and organometallic compounds at the well‐ordered surfaces.
Magic angle for surface roughness for intensity ratios in AES/XPS
Authors: Werner Wolfgang S. M.
Published: May 2005

The influence of surface roughness on total as well as angle‐dependent signal electron intensities has been studied by means of an effective and simple theoretical model. It was found that the influence of surface roughness may be accounted for in the usual formalism for AES/XPS by using an effective depth distribution function (DDF). Comparison of the model with experimental results and Monte Carlo calculations are very satisfactory and indicate that the model developed here should provide useful guidance for quantifying the influence of surface roughness in XPS/AES. For an emission angle of ∼ 35°, the depth distribution function assumes an exponential form with an effective attenuation length varying only by a few per cent as the relative surface area, which characterizes the roughness, is varied over a large range. This result implies that the influence of surface roughness on a given intensity ratio is very small for this geometry and may usually be neglected. This statement not only pertains to a layered sample but applies to a specimen with an arbitrary depth profile. Generally, the effective DDF is dominated by the influence of surface roughness, while the effects of elastic scattering are less pronounced. In this case, the combined influence of surface roughness and elastic scattering is simpler to describe than the influence of elastic scattering on the signal electron emission process from an ideally flat sample.
Ion yield effects in the SIMS analysis of silicon delta‐doped layers in GaAs
Authors: Sharma V. K. M. , McPhail D. S. , Fahy M. R.
Published: May 2005

Enhancements in the secondary ion yields of Si+ and As+ ions were observed in SIMS depth profiles of Si delta‐doped layers in GaAs when using oxygen primary ions. A systematic SIMS study of the enhancement in the intensity of the Si+ ion was carried out using a special test structure consisting of a series of layers with Si areal densities ranging from 0.01 monolayer (ML) to 2 ML (1 ML = 6.3 × 1014 Si cm−2). The enhancement effect was observed with layers above about 0.2 ML coverage and leads to erroneous measurements of the Si areal density for such layers. It was found that the level of the enhancement depended upon both the energy and angle of incidence of the oxygen ions. For a 2 ML delta, the level of the enhancement obtained with 5 keV O2+ ions at normal incidence was a factor of 1.2. However, using the same ion energy but changing the angle of incidence to 60° from the normal the enhancement obtained was almost a factor of 5. The enhancement was greatest when conditions for high depth resolution were used so that it was not possible simultaneously to achieve high depth resolution and accurate areal density measurements. The enhancements could not be removed by ratioing the silicon intensities to the As matrix lines (for which the enhancements are different). The enhancement effect was not observed when Xe+ or Cs+ primary ions were used and is predominantly an oxygen‐induced artefact.