bluuebunny/crossref_metadata_2025 huggingface dataset:
Complementary data of RBS, NRA and SIMS on diffusion processes during friction in nitride implantation films
Authors: Pivin J. C.
Published: May 2005

The purpose of the present paper is to discuss the possibilities and limits of three analytical techniques—namely RBS, NRA and SIMS—in studies of the worn surfaces of thin films. The chosen examples are not the most simple since the obtainable data by means of each technique are limited by the nature of the films, riders and atmosphere of friction tests. Surfaces of Ti or Fe implanted with N ions were worn in air against steel or silica balls, using a tribometer specially conceived for further surface analysis. Different mechanisms of oxidative wear have been shown based on the data of the above techniques and punctual complementary analysis by XPS or TEM. They are a diffusion of oxygen in the bulk of TiN, FeN solid solutions, through short paths and cracks in Ti2N, TiN compounds. In any case, the N diffusion during friction, which has been often invoked to explain the durable wear resistance of implanted metals, has not been observed.
Microcharacterization of micron/submicron fly ash from a pulverized‐dry‐coal‐burning power plant
Authors: Hazrati Azar , Schrodt J. Thomas
Published: May 2005

Micron/submicron fly ash particles from a pulverized‐dry‐coal‐burning power plant using an Eastern Kentucky bituminous coal, EKC no. 3, were subjected to physiocochemical microcharacterization analyses. These particles, when exposed to the beam of a transmission electron microscope, had their outer layers removed and as a result the appearance of their inclusions changed. Microchemical analysis by Auger electron spectroscopy (AES) revealed that splashed‐away layers were rich in sulfur and carbon with some coal‐originated, volatilized, condensed matter. The AES was used to analyze the composition of these layers and provide a thickness profile of the coating materials. Scanning electron micrographs revealed that the particles were partially hollow spheroids.
Sub‐micron molecular imaging. A viability study by time‐of‐flight SIMS
Authors: Briggs D. , Hearn M. J.
Published: May 2005

The possibility of sub‐micron imaging of molecular species on surfaces has been explored using a recently developed time‐of‐flight (TOF) imaging SIMS instrument which is equipped with a micro‐focused (∼500 Å) liquid metal ion source. Two model systems have been studied involving very thin (conducting) layers of organic materials on clean metals: a nonylphenol ethoxylate surfactant on gold and the peptide gly‐gly‐gly on aluminium.
Quantitation of coverages on rough surfaces by XPS: An overview
Authors: Fulghum Julia E. , Linton Richard W.
Published: May 2005

Selected methods for the XPS quantitation of surface coverages are summarized with an emphasis on non‐planar samples with overlayers, e.g. powders of high surface area. Equations have been modified for uniform terminology and are presented based on a photoelectron spectrometer with an E−1 transmission function. Approaches which require a minimum of information from independent analytical techniques are given special consideration. Quantitative schemes discussed include calibration curves, surface sensitivity factors, exponential attenuation of bulk signals by overlayers, catalyst models, and the use of subshell twins or peak shape distortions related to photoelectron energy losses.
Results of a SIMS round robin sponsored by ASTM committee E‐42 on surface analysis
Authors: Hues Steven M. , Colton Richard J.
Published: May 2005

The results of a round robin involving the quantitative depth profile analysis of ion‐implanted boron in silicon by secondary ion mass spectrometry are reported. This study was a blind analysis; each participant was provided with three samples, a standard for which the implantation does was known and two other samples of unknown dose. The study compares the accuracy and precision of the quantitative analysis of boron in silicon, background signal levels, detection limits, dynamic range and sputter depth profile shapes obtained using fifteen SIMS instruments (fourteen commercial instruments manufactured by five different companies and one home‐built system). The quantitative SIMS analysis of boron in silicon, using similar standards, was found to have a relative standard deviation of approximately 10–12%, which also turned out to be the variation in sample homogeneity over the implanted samples, and a relative error of <10%. Comparison of sputter profile shapes shows a good degree of precision extending over six decades of signal intensity. The highest dynamic range of 6.1 × 105 and the best detection limit of 3.7 × 1020 atoms m−3 were found for analyses using the ‘mini‐chip’ method of v. Criegern and Weitzel. Results of a test concerning the lateral homogeneity of the depth distribution of the implanted species are presented and discussed.
XPS study of the Al/Pd interface
Authors: Légaré P. , Finck F. , Maire G. , Roche R.
Published: May 2005

The formation of the interface between a Pd polycrystalline substrate and Al deposits was followed by photoemission. Interdiffusion takes place readily and shows an evolution with time as well as under electron irradiation. The thickness of the mixed layer depends on the thickness of the Al deposit. The effect results in a narrowing of the Pd valence states.
Surface analysis of air pollutants by XPS: Problems and experiences
Authors: Kövér L. , Tóth J. , Schág J. B. , Borbély‐Kiss I.
Published: May 2005

Problems and possibilities of air sampling (for surface analytical investigations) are discussed with particular attention to methods that fractionize particles by their sizes. Applications are illustrated by examples using metal and teflon surfaces as samplers. Biological samplers, such as leaves of different trees, proved to be applicable for XPS analysis and showed high sulphate content on their surfaces independent of the location of the three sampling sites. Independently of the methods and sites of air sampling a linear correlation has been found between the quantities of the surface carbon and nitrogen species characterized by their N 1s binding energies close to 400 eV, indicating surface bonds to carbon particles.
Reduction of charging in surface analysis of insulating materials by AES
Authors: Ichimura S. , Bauer H. E. , Seiler H. , Hofmann S.
Published: May 2005

Practical methods are investigated to reduce the charging which is often observed during AES analysis of insulating samples with keV electrons. It is shown that the negative charge caused by electron beams with keV energy can be either avoided or considerably reduced by the use of an additional electron beam or by the supply of low‐energy (500 eV) positive ions. It is also reported and discussed that the state of reduced or vanishing charging obtained by both methods can be maintained for long periods of time.
Optimized ion beam raster for SIMS sputter depth profiling
Authors: Mitchell D. F. , Arlow J. S. , Phillips J. R. , Sproule G. I.
Published: May 2005

A computer‐driven ion beam deflection system is described. This system allows custom tailoring of the ion beam raster to optimize SIMS depth profile performance. The ion beam is deflected to produce an approximately elliptical crater, which better matches the acceptance geometry of the ion extraction optics. A crater with a larger and more evenly flat bottom is produced by varying the resident time of the ion beam within the raster area, thus allowing for the collection of more signal with better depth resolution. This is accomplished by creating an array of equally spaced sputter points on the sample, taking into account the orientation of the ion gun and the SIMS optics with respect to the sample normal. The resident time of the ion beam along the crater perimeter is extended and the raster and mass spectrometer are synchronized. The improvement in performance is shown using a strain layer superlattice test sample 720 nm thick, consisting of 40 double layers of Si/Si–30% Ge.
Characterization of CuO–ZnO catalysts by X‐ray photoelectron spectroscopy: Precursors, calcined and reduced samples
Authors: Moretti G. , Fierro G. , Lo Jacono M. , Porta P.
Published: May 2005

X‐ray photoelectron spectroscopy was applied to characterize CuO–ZnO catalysts (Cu/Zn atomic ratio ≥ 1) prepared by thermal decomposition at 350°C in air of hydroxycarbonate precursors obtained by the coprecipitation method at constant pH.

For the precursors, the surface Cu/Zn atomic ratios have, within experimental error, the same values as that obtained by chemical analysis. This shows both a homogeneous dispersion of zinc in the zincian‐malachite solid solutions for the samples Cu/Zn = 92/8, 85/15 and 77/23, and a good interdispersion of the zincian‐malachite and aurichalcite phases in the 67/33 and 50/50 samples.

In our calcined samples we find a strong interaction between the small oxide particles but no evidence of Cu2+/ZnO and Zn2+/CuO solid solutions. In the catalysts with low zinc loading, the ZnO phase (amorphous or with particles of a size < 40 Å) tends to cover the CuO particles. The catalysts with high zinc loading present the differential charging phenomenon due to the peculiar morphological situation of CuO and ZnO particles, as shown by the XPS measurements of samples supported on a biased sample holder.

The reduction in situ under H2 at 135 and 200°C of these catalysts shows that Cu and Cu+ (Cu2O‐like) species are formed. Cu+ species are present even at high extents of reduction but the kinetics of the reduction and the relative amounts do not seem to be influenced by the presence of the ZnO phase. These findings are in agreement with our previous characterization with bulk techniques.

A critical comparison with previous published papers dealing with XPS characterization of real and model catalysts is presented.
Quantitative AES and XPS investigation of magnetron sputtered TiNx films
Authors: Bender H. , Portillo J. , Vandervorst W.
Published: May 2005

The possibilities for quantitative compositional analysis of TiNx layers prepared by d.c. magnetron sputtering with Auger electron spectroscopy and x‐ray photoelectron spectroscopy are discussed. As an alternative to the AES quantification schemes reported in the literature, methods based on the ‘peak‐to‐peak‐minus‐x‐eV‐height’ and ‘factor analysis’ are examined. Different background subtraction methods are studied for the XPS quantification.
Spatial resolution tests of scanning Auger microscopy under different topographical conditions
Authors: Umbach A. , Hoyer A. , Brünger W. H.
Published: May 2005

Highly focused electron beams have been scanned across chemical edges of different surface structures in a scanning Auger microscope with a field emission gun. For the case of a fracture plane across a multilayer structure with 100 nm Ta and 100 nm Si layers, a resolution of 35 nm for the Ta signal and 53 nm for the Si signal was found.

In contrast to these flat samples, analytical problems in semiconductor technology require analysis of submicrometre features with high aspect ratios. Under these conditions, the scanning Auger microscopy (SAM) resolution is drastically affected by electron scattering. To study these effects, we used x‐ray mask structures consisting of 0.6 μm high Au on Si (100) fabricated by x‐ray lithography.

We scanned over a heterogeneous step of this kind with the three different electron beam energies 10, 20 and 30 keV and measured the lateral intensity distribution of the Si signal. This signal does not stop at the edge but extends into the gold plane over a distance that increases with beam energy as expected.

When analysing small features, this effect leads to a misinterpretation of the Auger spectra. This problem becomes more severe as the feature size is reduced. This has been demonstrated for gold bars of different widths and different sized columns.

To minimize the contribution of nearby regions to the spectrum, the lowest beam voltage is recommended, which is sufficient to achieve the required beam diameter.
VAMAS surface chemical analysis technical working party: An update for 1988
Authors: Seah M. P.
Published: May 2005

A brief overview is presented of the VAMAS Surface Chemical Analysis Technical Working Party project. This project is aimed at providing the reference working base for surface analysis. There are currently 20 projects covering AES, XPS, SIMS, sputtered neutral mass spectrometry and sputter‐depth profiling. The coordination of the projects leads to considerable gains in confidence and in project output, together with a reduction in the workload necessary to meet the project targets. This arises simply because of the increased availability of characterized samples, reference methodologies and software within the overall programme. This Technical Working Party has been active for 4 years now and definitive milestones are being achieved that would be impossible without the overall coordination.
Investigation of the early stages of thin‐film growth of Ni on thermally grown SiO2 by means of RBS, AES and TEM
Authors: Anklam H.‐J. , Mattheis R. , Thrum F.
Published: May 2005

To study the type of growth of Ni on thermally grown SiO2 three analytical methods, RBS, AES and transmission electron microscopy (TEM), were used. An SiO2 thickness of ∼ 30 nm has been proved to give optimal conditions with respect to sample preparation and measurement.

On identical samples the differential sticking coefficient (by RBS), type of growth (by AES) and saturation cluster density (by TEM) have been determined in dependence on substrate temperature.

The growth can be characterized by a pseudo‐Stranski‐Krastanov mechanism with incomplete condensation for substrate temperatures exceeding 575 K and a high saturation cluster density (∼ 3 × 1012 cm−2) that is independent of substrate temperature.
Contributions of AES in four metallurgical studies
Authors: Grabke Hans Jürgen
Published: May 2005

Four recent studies are reported characterizing the possible contributions of surface science to metallurgy. The grain boundary segregation of phosphorus was studied by AES analyses of fractured specimens—after many studies on ferritic iron steels—in the austenitic range for FeP, FeMnP, FeCP and FePB alloys. Also, in Ni20% Cr the grain boundary segregation of P and its effects on carbide precipitation were investigated.

On surfaces of ternary alloys FeMI, co‐segregation of the metal M and non‐metal element I can lead to the formation of two‐dimensional or three‐dimensional surface compounds, as demonstrated for the system FeCrN. The formation of such nitrides in the first transient state of the oxidation of high‐temperature alloys can strongly deteriorate the protective properties of the chromia layer formed—as shown for the oxidation of Fe20% Cr in N2H2OH2.
Analysis of epitaxial CdxHg1 − xTe layers using RBS, SIMS and EER
Authors: Diskett D. J. , Avery A. J. , Blackmore G. , Irvine S. J. C. , Giess J. , Berlouis L. E. A.
Published: May 2005

A combination of the techniques of Rutherford backscattering spectrometry (RBS), secondary ion mass spectrometry (SIMS) and electrolyte electroreflectance (EER) have been used to profile through epitaxial layers and heterostrutures of CdxHg1 − xTe. The layers analysed by these techniques were grown either by photosensitized or thermal metal organic vapour phase epitaxy (MOVPE). The use of the EER technique, combined with electro‐chemical etching, for depth profiling of layers is described. Good agreement between RBS and EER measurements of x has been achieved with a resolution of ±0.010 for RBS and ±0.002 for EER. A depth resolution of better than 50 Å has been achieved by all three of the techniques. SIMS has been used to profile for trace impurities in layers grown using the interdiffused multilayer process (IMP). Assessment of layer crystal quality using ion channelling and EER broadening parameter measurements is discussed. The advantages and disadvantages of each of the analysis techniques are discussed and compared.
Comparison of beam‐induced profile broadening effects of gallium and copper in oxygen‐bombarded silicon
Authors: Homma Yoshikazu , Maruo Tetsuya
Published: May 2005

Oxygen‐induced profile broadening in secondary ion mass spectrometry (SIMS) has been studied for Ga and Cu in silicon under 10 keV O2+ bombardment at impact angles of 2–82°. A beam‐induced broadening effect was evident for impact angles <30° to the surface normal. In this range of impact angles, the SIMS signal of Cu showed exceptionally long decay, and its decay length decreased with increase in impact angle. By contrast, the decay length of Ga had a maximum at around 27° and decreased below this value. This difference in decay behaviour is attributed to the difference in impurity transport during beam‐induced oxidation. While Cu segregates at the SiO2/Si interface, Ga diffuses rather uniformly in the surface SiO2 layer.
Non‐destructive depth profiling through quantitative analysis of surface electron spectra
Authors: Tougaard S. , Hansen H. S.
Published: May 2005

A theory is presented that allows detailed quantitative information on in‐depth concentration profiles to be extracted through analysis of surface electron spectra. The depth profile is determined from analysis of a single spectrum and the method is therefore fast and non‐destructive. The validity of the method is tested through anlaysis of model spectra from a wide variety of inhomogeneous systems. It is demonstrated that the method can clearly distinguish between different classes of in‐depth profiles. Moreover, the formalism can be used to distinguish between different overlayer growth mechanisms. The resolution in the determination of the detailed concentration depth profile is of the order of the inelastic mean free path λ. The accuracy of the total amount of material within depths of 4–6 λ determined by the analysis is, in all cases, better than 10–15%.
Secondary ion yield matrix effects in SIMS depth profiles of Si/Ge multilayers
Authors: Gillen Greg , Phelps John M. , Nelson Randall W. , Williams Peter , Hues Steven M.
Published: May 2005

Thin multilayer samples of Si/Ge, with individual layer thicknesses of 4–33 nm, have been analyzed by secondary ion mass spectrometry (SIMS) using Ar+, O2+ and Cs+ primary ion beams. Bombardment with both Ar+ and O2+ produced positive secondary ion depth profiles in which pronounced distortions were observed. Similar effects were found in negative secondary ion depth profiles with Cs+ bombardment. In each case, the SIMS depth profiles were characterized by abrupt interfacial secondary ion signal variations and a shift in the secondary ion signal maxima indicating that the layers were superposed, a condition that was not consistent with sample preparation, as verified by Auger electron spectroscopy. Auger electron spectroscopy depth profiling was also used to quantify the level of oxygen in the films. From these data it was concluded that the distortions in the positive secondary ion depth profiles under Ar+ bombardment were the result of secondary ion yield variations induced by enhanced incorporation of ambient oxygen, during sample preparation, into the stronger oxide‐forming silicon layers. Under O2+ and Cs+ bombardment, the profile distortions were introduced by differential incorporation of the implanted primary species into the lower‐sputter‐yield silicon layers.
Surface analysis preparations for multilayer plated through‐holes
Authors: Love Brian J.
Published: May 2005

Surface analysis on multilayer printed wiring board interconnections has been, at best, difficult to achieve. This has been primarily related to geometric considerations, which prevent adequate detection of x‐rays, Auger emissions, etc. We have developed a method for analysing solder defects on plated through‐holes via a microsectioning technique to generate a coupon and then embedding the coupon in conductive foil for analysis. Samples are shown that have been produced using this technique. Reasonable spectra have been generated on specimens prepared by this technique. This preparation allows analysis on soldered holes, which, because of geometric constraints, are difficult to analyse.
Detection of substrate‐related species during depth profiling of a‐Si: H films with SIMS
Authors: Herion J. , Beyer W. , Wagner H.
Published: May 2005

Thin films of hydrogenated amorphous silicon (a‐Si:H) were deposited on various substrates (e.g. Cr, Ti, GaAs) and analysed by secondary ion mass spectrometry (SIMS). Depth profiles were measured using oxygen ions of 9 keV as a primary beam. Spatially resolved (or imaging) SIMS was used to determine the local distribution of the various species. At nearly normal incidence of the primary beam, the intensity of substrate‐related species showed a step‐like increase at ∼ 20% of the film thickness and remained at a relatively high level throughout the rest of the film. For substrates consisting of Cr films evaporated on crystalline silicon, variations of the deposition temperature and of the thickness of the a‐Si:H films did not markedly influence the phenomenon. By changing the angle of incidence of the primary beam, a considerable shift of the step towards the interface between the film and the substrate was obtained. The results of depth profiling experiments, of imaging by SIMS and optical microscopy can be explained qualitatively by a beam‐induced effect.
RBS and ERD analysis of semiconductor device materials
Authors: Kuiper A. E. T.
Published: May 2005

The number of applications of Rutherford back‐scattering spectrometry (RBS) in the field of integrated circuit (IC)‐related materials research is ever‐increasing. Both qualitative and quantitative information about thin‐film material can be derived from a single RBS spectrum, as is demonstrated from various example that are typical for semiconductor research. Such examples include kinetic studies of thin‐film reactions. The RBS facility constructed at Philips Research Laboratories in Eindhoven for in situ investigations is described.

Hydrogen, which in principle cannot be detected in RBS, can be measured with the related technique of elastic recoil detection (ERD). ERD can be performed readily in conventional RBS equipment, which adds to its attractiveness as a complementary technique. Examples are discussed to show how RBS and ERD combine in characterizing thin films.
The drastic effect of oxygen on surface segregation
Authors: Mezey L. Z. , Hofer W. , Varga P. , Giber J.
Published: May 2005

The temperature and oxygen partial pressure of the environment of a solid may produce non‐oxidizing or oxidizing conditions for any of the components in the surface. Under non‐oxidizing (free surface) conditions, one of the components of a binary alloy segregates. The oxidizing effect may enhance or diminish its surface content, and the other component may even segregate. This effect is investigated here using the experimental results (ISS and AES) and theoretical calculations of a new method. Agreement between theory and experiment is shown for AuPd and CuPd, and as well for S‐contaminated CuFe.
Surface characterization of rhodium–copper alloys
Authors: Delplancke M. P. , Jardinier‐Offergeld M. , Bouillon F.
Published: May 2005

This paper presents the results of a surface analysis of copper–rhodium alloys by Auger electron spectroscopy during heat treatments under vacuum. It is shown that copper segregation takes place in the first atomic layer at every rhodium concentration. Special attention is given to the influence of diffusion rate on the composition of the surface region. The results are compared with theoretical models. A segregation enthalpy is determined for a 1.5 at.% Rh alloy at 873 K.
Role of oxygen contamination on titanium nitriding
Authors: Saillard P. , Gicquel A. , Amouroux J. , Moncoffre N. , Tousset J.
Published: May 2005

Titanium nitridation has been achieved in a tubular reactor under a radio frequency low‐pressure plasma. The influence of the plasma working parameters (substrate temperature, nature of the gas phase and plasma input power) on the superficial nitride/oxide ratio has been investigated. The influence of the oxygen bulk contamination on nitridation kinetics is also reported.
Immersion ellipsometry of semiconductor surfaces
Authors: Ohlídal Ivan , Líbezný Milan
Published: May 2005

In this paper, three methods of immersion ellipsometry based on measuring the ellipsometric parameters in air and non‐absorbing liquids are used for analysing silicon, germanium and gallium arsenide single crystals covered with very thin native oxide layers under normal laboratory conditions. If the values of the extinction coefficients of the semiconductors are known with sufficient accuracy, the values of the refractive indices of these semiconductors and the thicknesses and the refractive indices of the effective surface layers can be determined with satisfactory or high accuracy (the effective layer represents a double layer consisting of the native layer and the interface layer). If the values of the optical parameters characterizing the interface layer between the silicon substrate and its native oxide layer are known, the values of both the thickness and the refractive index of the native oxide layer can be determined. The values of all the optical parameters (including the extinction coefficient) of the system formed by a silicon surface covered with the native oxide layer can be determined with good accuracy if the experimental data corrresponding to this system are interpreted together with those corresponding to a silicon surface covered with a thick SiO2 (amorphous) film. This procedure can be used if the values of the optical parameters of the interface layer are known in a reliable way. The methods are applied at a wavelength of 632.8 nm.
An ELS and AES study of InP(100) surfaces during Sb atom condensation
Authors: Gruzza B. , Pariset C. , Abdellaoui S.
Published: May 2005

Auger electron spectroscopy (AES) and electron loss spectroscopy (ELS) have been performed in order to investigate InP (100) surfaces subjected to a controlled Sb deposition.

The combination of these two electron spectroscopies and a fine analysis of AES signals as a function of surface coverage allows us to propose a model for the formation of Sb/InP interfaces.

Indium droplets present on the sample after Ar+cleaning disappear during the first Sb deposit to form an InSb surface compound, which gives the surface great stability.

If the deposit is formed at a high temperature after this first stage, no more Sb atoms can be condensed, whereas at room temperature the growth mode is of the Franck Van Der Merwe type.
SIMS of microelectronic structures using a liquid metal ion gun
Authors: Bishop H. E. , Greenwood S. J.
Published: May 2005

A 30 keV gallium ion beam with a minimum probe size of 50 nm has been used as the primary beam in the SIMS examination of microelectronic devices. By operating this gun at a 2 nA probe current, 20 μm square pits have been machined through selected areas of a device. The incident angle of the beam is 60°, so that one pit wall forms a 30°taper section through the device. Secondary electron and ion images from this section reveal the subsurface structure in detail. Oxide and nitride layers as thin as 40 mm can be identified readily and traces of fluroine and chlorine from processing have been observed.
Surface analytical scanning electron microscopy in ultrahigh vacuum combined with scanning tunnelling microscopy
Authors: Ichinokawa T.
Published: May 2005

A scanning electron microscope of ultrahigh vacuum with a field emission gun is operated at primary energies in the range 100 eV to 3 keV. The instrument can form the images that contain information on surface chemical composition, chemical bonding state (electronic structure) and surface crystal structure at a microscopic resolution of several hundred angstroms (Å) using the techniques of scanning Auger electron microscopy, scanning electron energy‐loss microscopy and scanning low‐energy electron diffraction (LEED) microscopy. Scanning tunnelling microscopy (STM) also has been combined with a SEM in order to obtain the atomic resolution for the solid surface.

The instrumentation and examples of their applications are presented both for scanning LEED microscopy and STM.
Application of an STM/SEM instrument for the study of materials: Tip effects and data correlation
Authors: Gómez‐Rodríguez J. M. , Vázquez L. , Baró A. M.
Published: May 2005

We have used scanning tunnelling microscopy (STM) to study the surface topography of several materials in the nanometre range. In order to solve some problems of STM, we have integrated it with a conventional scanning electron microscopy (SEM). The aim of this paper is to analyse critically this combination. We emphasize the importance of tip effects in STM, for which purpose we use the image of the tip obtained by SEM. Also, we correlate the images obtained by both techniques in order to gain insight into the operation of both microscopes. In summary, we find that this combination represents an important step in the study of the surface topography of materials of technological interest.
A new SIMS instrument for submicron microarea analysis
Authors: Nomura S. , Shichi H. , Mitani E. , Izumi E.
Published: May 2005

A new type of SIMS instrument has been developed for submicron microarea analysis. The instrument is incorporated with an electron beam, which provides scanning electron microscopy (SEM) images of a sample. The operator determines the area to be analysed by observing the SEM image without damaging the sample, then switches the electron beam to an ion beam and carries out a SIMS analysis of that area. Electron and ion Beams with diameters of <20 nm and <70 nm, respectively, are focused on the sample. Some application data of the micro‐area elemental analysis are presented.
The Auger parameter and the polarization energy: A simple electrostatic model
Authors: Moretti G.
Published: May 2005

In this paper we discuss the core‐hole screening mechanisms in the framework of the model proposed by Veal and Paulikas. If only the polarization of the ligands contributes to the relaxation energy, the non‐local screening mechanism, then the Wagner Auger parameter shifts can be estimated by a simple electrostatic model that takes into account the number, the distance and the electronic polarizability of the first neighbours of the atom with the core hole.

The model has been verified for several compounds, comparing the calculated polarization energies with the experimental values obtained via the Auger parameter data taken from the literature. The same approach cannot be applied to systems containing the late transition metal ions for which a local screening mechanism occurs by a charge transfer from the ligand to the spatially localized d levels. The Auger parameter obtained from the main core photoemission peak of the late transition metal ions is almost insensitive to the chemical nature of the ligand itself and the screening energy is similar to that observed in the metallic state. In this case, the relaxation energy can be estimated from the energy separation between the main and the satellite structures in the core photoemission peak.
Quantitative surface analysis (AES) of SiC
Authors: Jørgensen B. , Morgen P.
Published: May 2005

We present an analysis of the critical factors for the determination of surface concentrations from derivative Auger spectra. A new spectroscopic quantity, Pσ2, should supersede the peak‐to‐peak signal. This quantity is the product of the negative‐peak‐to‐background value, P, multiplied by the square of the width of the peak, σ. The method is applied here to Si and C in an SiC sample, but will apply to any multicomponent system. The analysis needs the derivative Auger spectra of the clean components and the sample in question. We also examine relevant changes in material properties between the reference materials and the SiC sample, as several properties of the SiCSiC system vary owing to large differences in atomic densities for the three materials. In this system, lineshapes, back‐scattering of primary electrons and inelastic mean free paths vary for the Auger electrons. Our analysis shows that the lineshape changes could induce errors in directly derived, uncorrected concentrations by factor of 2 (for SiC), while the two other corrections are on the 10% level. With the present method, an Ar ion bombarded surface of SiC shows only a slight enrichment of C, which is much less pronounced than without the corrections.
XPS and UPS studies of gas‐phase oxidation, electrochemistry and corrosion behaviour of Ti and Ti5Ta
Authors: Siemensmeyer B. , Schultze J. W.
Published: May 2005

Owing to its high corrosion resistance, Ti is used as a containment material for processes in hot nitric acid. The corrosion stability of Ti can be improved still further by alloying with 5% Ta. The oxidation behaviour of Ti and Ti5Ta and the composition and stability of their oxide layers are compared by means of XPS, UPS, electrochemical measurements and corrosion test. Thin oxide layers of up to 2 nm have been formed by gas‐phase oxidation. Three regions can be observed due to chemisorption, oxide formation and oxide growth. The average composition of the oxide layer after an oxygen exposure of 1000 L is Ti2O3, with a layer thickness of 1.8 nm. The change of Ti oxidation states during oxidation shows that the metal/oxide interface is a mixed oxide of TiO, Ti2O3 and TiO2, while TiO2 is formed at the oxide/vacuum interface. The change of work function during oxidation is similar for Ti and Ti5Ta.

Thicker oxide layers have been built electrochemically, with no differences in capacity measurements between Ti and Ti5Ta, indicating similar electronic properties. No significant Ta enrichment in 1 N H2SO4 and 1 N HNO3 is found up to 10 V. Preferential dissolution of Ti in corrosion tests in hot HNO3 leads to Ta enrichments by factors of >10, which explains the improved corrosion stability of the alloy. The surface is covered by a barrier oxide of ∼10 nm and a porous outer layer with a thickness of >50 nm.
Effect of pretreatment on a platinized tin oxide catalyst used for low‐temperature Co oxidation
Authors: Drawdy Jean E. , Hoflund Gar B. , Gardner Steven D. , Yngvadottir Eva , Schryer David R.
Published: May 2005

A commercial platinized tin oxide catalyst used for low‐temperature CO oxidation has been characterized using ion scattering spectroscopy, Auger electron spectroscopy and electron spectroscopy for chemical analysis before and after reduction in 40 Torr of CO for 1 h at various temperatures in the range 75–175°C. The reduction results in loss of surface oxygen, formation of metallic tin, conversion of platinum oxides to PtOSn and Pt(OH)2 and a small amount of metallic Pt which alloys with the tin. These results should be useful in understanding how the pretreatment temperature affects the catalytic activity of platinized tin oxide toward CO oxidation.
XPS intensities and binding energy shifts as metal dispersion parameters in Ni/SiO2 catalysts
Authors: Gonzalez‐Elipe A. R. , Munuera G. , Espinos J. P.
Published: May 2005

A set of Ni/SiO2 catalysts with metal loadings between 1 and 8% by weight has been prepared by several methods. Metal dispersions have been determined by H2 chemisorption and x‐ray line broadening analysis, giving metal particle sizes from ∼30 to 250 Å.

XPS analysis of the samples has been recorded after reduction in situ and the data correlated with the metal loading and metal dispersion. When comparing the Ni 2p intensities, a good relationship has been obtained with metal surface concentration, showing the existence of two well‐defined set of catalysts with particles of quite different sizes. However, a single linear relationship is obtained for all the samples when the Ni 2p binding energies are plotted against the metal dispersion calculated from H2 chemisorption. The origin of the binding energy shift and its relation with metal dispersion is discussed.
FTIR study of nickel and copper oxidation: Theoretical approach and experience
Authors: Machefert J. M. , Le Calvar M. , Lenglet M.
Published: May 2005

The behaviour of the specular reflectance of several oxides on metals (Cr2O3 on Cr, Cu2O on Cu) has been studied theoretically and experimentally in the infrared region. Theoretical and experimental are in accordance with each other. The results obtained on pure metals are applied to the sudy of 80 Ni‐20 Cr and 55 Cu‐45 Ni alloys in order to identify the oxides grown on the oxides grown on the surface during thermal oxidation.
A general and simple approach for the determination of energy analyser transmission functions
Authors: Carrazza José , León Vladimir
Published: May 2005

The transimmison function of energy analyzer LHS‐11 from Leybold‐Heraeus has been obtained from the dependence of the signal intensity on the instrument pass energy (Ep) at a given kinetic energy of the incident electrons (Ek).

For the energy analyzer, the transmission function has been expressed by the equation

A slight dependence of the exponent n on Ek is observed, and it has been fitted by the equation

This is a very general characterization of the transmission that gives its analytical description in the whole XPS range for a given set of operational parameters, such as slit dimensions, sample size and sample position.

From the transmission function obtained and using reported values of the photoionization cross‐sections, two sets of XPS sensitivity factor for several elements have been calculated. With these factors, the surface concentrations of a multi‐element sample have been determined with good agreement between the values after Mg and AI Kα excitation. These results suggest that corrections due to variations in the transmission function with Ek can improve the accuracy of the calculated sensitivity factors.
X‐ray photoelectron spectroscopic studies of the bonding of phenyl sulfides to copper
Authors: Beecher James F.
Published: May 2005

The chemisorption and bonding of different phenyl sulfides with copper have been studied by x‐ray photoelectron spectroscopy (XPS). Volatile phenyl sulfides were employed: phenyl mercaptan, diphenyl sulfide and diphenyl disulfide. The reactions were conducted in an evacuated chamber adjacent to the analytical chamber of the XPS spectrometer so that the oxidation state of the copper could be controlled.

Chemisorption and bonding depend both upon the phenyl sulfide species and the oxidation state of copper. The mercaptan reacts with copper in either state; oxygen is displaced from the oxidized copper surface and copper phenyl mercaptide is formed. Phenyl sulfide does not react with copper metal but displaces oxygen from the oxidized copper, along with the formation of a mercaptide. Diphenyl disulfide forms a mercaptide with unoxidized copper but does not react with oxidized copper. Some evidence for the formation of another unknown sulfide species is found in the reaction of diphenyl disulfide with copper.
Periodic variations in the nitrogen KLL Auger intensity from interstitial nitride films
Authors: Dawson Peter T.
Published: May 2005

Transition metal nitride films have been prepared by reaction of ammonia gas at 300 Torr pressure with nine different transition metals at high temperatures in the range 900–1200°C. The films produced were typically microns thick and could therefore be characterized by x‐ray diffraction, in addition to Auger electron spectroscopy and scanning electron microscopy. Strong periodic variations in the intensity of the nitrogen KLL Auger emission have been observed from the nitrides of Ti, V, Cr, Zr, Nb, Mo, Hf, Ta and W. The measured nitrogen signal was observed to decrease within each group, and also across each period. These results are discussed with reference to matrix effects in the Auger emission and the stability and structure of the interstitial nitrides.
Surface treatment of aluminum and titanium: From basic research to production failure analysis
Authors: Davis Guy D.
Published: May 2005

High‐performance adhesive bonds require clean, microscopically rough adherend surfaces that are compatible with the adhesive or primer. Such surface allow wetting by the polymer and a complete filling of the pores of ‘nooks and crannies’. The resulting mechanical bonds supplement or supplant the chemical bonds present. For durability in aggressive environments, aluminum bonds that are exposed to high humidity also require hydration‐resistant oxide surfaces. Such hydration resistance is inherent in some surfaces, e.g. phosphoric acid‐anodized surfaces, and can be high temperatures, such bonds require oxide‐free surfaces when exposed to temperatures above 300°C. These surfaces can be formed by plasma spraying a metallic powder coating onto the titanium alloy. Although preparation of high‐quality surfaces and bonds is achieved readily in the laboratory, occasional failures are observed in the manufacturing environment owing to, for example, contamination, pH or temperature variations. These processing problems can prevent wetting of the surface or can destroy the microrough morphology. A basic understanding of the mechanisms involved in the production of appropriate surfaces and their resulting adhesive bonds and in their degradation is critical to the evaluation of the failures and their remedy.
Pretreatments of improve the adhesion of electrodeposits on aluminium
Authors: Monteiro F. J. , Barbosa M. A. , Ross D. H. , Gabe D. R.
Published: May 2005

Aluminium is generally regarded as a metal that is difficult to plate. By using a pretreatment sequence, which includes immersion in a zincate solution, it is possible to electroplate aluminium successfully, although adhesion levels are not always very high. Zincate solutions modified by the addition of various ions have been shown to promote adhesion. Using one such solution, an investigation has been carried out as to how, by modifying the pretreatment sequence, the adhesion on electrodeposits on aluminium can be improved. Such modifications included varying the etch procedures and using the so‐called double dip technique. Some of the factors giving rise to the improved adhesion of electrodeposits have been investigated by SEM, AES, SIMS, ESCA, EPMA and AAS.
AES/GDS characterization of thin oxide films on FeCr sheet steels
Authors: Suzuki S. , Suzuki K.
Published: May 2005

Thin oxide films on four kinds of commercial sheet were characterized with Auger electron spectroscopy (AES) and glow discharge optical emission spectroscopy (GDS). Enrichment of alloying elements was noticed in the thin oxide films formed in air. The depth profiles obtained by AES with ion sputtering showed that enrichment of chromium occurred at the interface between the oxide and the matrix. It was difficult with AES to obtain the profiles of silicon and manganese because of overlap of their peaks with the iron peaks on the spectrum. On the other hand, with GDS, silicon and manganese could be analysed quantitatively in thin films that are <0.05 μm thick.
Facts and artefacts in the characterization of Si/SiGe multiayers with SIMS
Authors: Zalm P. C. , Vriezema C. J. , Gravesteijn D. J. , van de Walle G. F. A. , de Boer W. B.
Published: May 2005

A number of Si/Si1−x Gex heterostructures, grown by molecular beam epitaxy (MBE) and vapour phase epitaxy (VPE), were examined with secondary ion mass spectrometry (SIMS). A variety of experimental conditions was employed, limited to positive secondary ions and moderate to excellent depth resolution. The most elaborate results were obtained for O2 + primary ion bombardment at energies of 2–8 keV. These demonstrate (for x < 0.4): (1) a minimal erosion rate variation with germanium content x; (2) the near‐absence of matrix effects, i.e. x dependence, of the secondary ion yields for impurities like B, Ga, Sn, Sb and others; (3) an approximately concentration‐independent sensitivity for germanium. Furthermore, a surface‐energy‐difference‐driven, Ge‐segregation mechanism operative during MBE growth is discussed. This phenomenon is just one manifestation of the fundamentally different processes during MBE and VPE. Such processes may be responsible for the fact that interfaces in MBE samples, as obtained with SIMS, are loss abrupt than for VPE material. A simple explanation in terms of an inferior substrate‐cleaning procedure cannot be ruled out, however.
Noval detection scheme for the analysis of hydrogen and helium by secondary ion mass spectrometry
Authors: Gnaser H. , Oechsner H.
Published: May 2005

For the analysis of hydrogen and helium in solids and thin films by secondary ion mass spectrometry, the use of Cs+ primary ions in conjunction with the detection of HCs+ and HeCs+ molecular ions is proposed. For both species, detection limits of the order of 1019 atoms cm−3 are obtained at sputter removal retes of ∼1 nm s−1. A relative depth resolution of ∼2% is demonstrated for hydrogenated amorphous Is layers on single‐crystal Si. In these specimens, the HCs+ intensities scale linearly with the hydrogen concentrations cH in the range investigated (cH < 20at.%); hence, a quantitative evaluation of the H content appears possible by means of a single standard.
Structure of the adsorbed ethyl xanthate monolayer on copper
Authors: Laajalehto K.
Published: May 2005

XPS intensity calculations from completely oriented and randomly oriented ethyl xanthate on copper have been made as a function of electron take‐off angle. Corresponding experiments also were carried out using the variable‐angle XPS (VAXPS) method. The results show that the completely oriented ethyl xanthate layer model at a certain stage of adsorption seems to be valid, as originally proposed by Mielczarski et al. However, there are systematic errors in the calculations, which are mainly due to uncertainties in calculated electron mean free paths and absolute values of parameters characterizing the assumed adsorption layer structure.
Analytical expression describing the attenuation of Auger electrons and photoelectrons in solids
Authors: Werner W. S. M. , Gries W. H. , Störi H.
Published: May 2005

The attenuation of Auger electrons and photoelectrons in solids as described by the so‐called depth distribution function (DDF), has been studied by means of a Monte Carlo simulation of electron transport in matter. Elastic scattering plays a significant role in the model. Based on the results of a large number of simulations, an empirically derived analytical expression for the DDF is proposed that includes the effects of elastic scattering. As part of this analytical DDF, a new attenuation parameter (AP) is introduced, which being a material constant independent of emission angle and layer thickness, can assume a central role in quantitative AES and XPS. The proposed AP as well as the general validity of the results is discussed. Most importantly, a simple relationship between the most significant quantities governing the transport of electrons in transport of electrons in solids, i.e. the inelastic mean free path (IMFP), the total mean free path (TEMP) and the attenuation parameter, was derived from the results. By a single Monte Carlo simulation, the AP can be determined. The DDF for different experimental geometries, film thicknesses, etc. can then be determined analytically.
Quantitative surface chemical analysis of AuCu alloys with XPS
Authors: Yoshitake M. , Yoshihara K.
Published: May 2005

The work of VAMAS‐SCA project no. 25 is reported. The project was an XPS round robin with thgree different compositions of AuCu alloys (Au 25 at.%,–Cu 75 at.%, Au 50 at.%–Cu 50 at.%, Au 75 at.%–Cu 50 at.%.). These alloys were alson the subject of an earlier AES round robin ( VASMAS‐SCA project no. 17). Pure gold and pure copper was used as the standard materials. By using peak areas of the Au 4f doublet and Cu 2p3/2 for the calculation, the effects of measurement conditions and data processing on quantification were examined. The reliability of quantification by three methods, namely the ‘relative sensitivity factors’ method, the ‘pure metals as standard materials’ method and the ‘alloy as standard material’ method, was compared. It is concluded that measurement conditions such as photoelectron emission angle and energy resolution did not affect quantification and that there was no effect of the different background subtraction methods on quantification. With the ‘alloy as standard material’ method, variations of the measured surface concentrations were the smallest, namely ∼2–6%.