bluuebunny/crossref_metadata_2025_split huggingface dataset:
SIMS analysis, under caesium bombardment, of Si in GaAs/(Al, Ga) as superlattices: Detection limit and depth resolution
Authors: Gauneau M. , Chaplain R. , Regreny A. , Salvi M. , Guillemot C. , Azoulay R. , Duhamel N. 
Published: May 2005

AbstractSilicon is widely used for n‐doping of GaAs/(Al, Ga)As layered structures grown by molecular beam epitaxy or metallo‐organic chemical vapour phase deposition for high speed and opto‐electronic devices, so the determination of Si doping levels in these structures is of primary importance. The secondary ion mass spectrometry technique has been revealed as a very powerful method for such a determination. But, in this particular case, some difficulties are encountered at low doping levels because of the presence of ions interfering with the main silicon isotope at mass 28. This paper deals with the search for satisfactory experimental conditions for such a silicon analysis under caesium primary ion bombardment, the main requirements being the detection limit and the depth resolution. It will be shown that AIH molecular ions are the interfering species and two approaches have been explored to avoid this interference: use of high mass resolving power facilities of a double focusing mass spectrometer, or experimentation at low vacuum conditions. A compromise is ineviatable between maximum sensitivity in the 1–2 1015 cm−3 range by detecting negative secondary ions and good depth resolution, equal to about, 40 Å, by using positive secondary ion collection. The ultimate performances of the technique are limited by the silicon surface segregation process and factors like the initial surface morphology of the samples, the flatness, and parallelism with the surface, of the crater bottoms and the beam induced roughness.
TOF‐SIMS analysis of the surface of insulators. Examples of chemically modified polymers and glass
Authors: Lub J. , van Velzen P. N. T. , van Leyen D. , Hagenhoff B. , Benninghoven A. 
Published: May 2005

AbstractA metod to compensate for surface charging of insulator surfaces during TOF‐SIMS experiments is described. For this purpose a pulsed low energy electron source is used, immediately after the ion extraction period. The surface potential is self adjusting, resulting in a stable spectrum. Besides, ESD effects are strongly suppressed. Positive and negative ion spectra of thick PMMA and PC substrates, containing surface active additives and of UV‐ozone cleaned glass substrates before and after trimethylsilylation are presented. From the glass samples the positive ESD spectra were also recorded by using a continuous electron beam. Comparison between the SSIMS and ESD results indicates that ESD is more surface sensitive and sufferes less from ion fragmentation than SSIMS.
Redeposition in AES sputter depth profiling of multilayer Cr/Ni thin films
Authors: Zalar A. , Hofmann S. 
Published: May 2005

AbstractDuring sputter depth profiling, a part of the sputtered matter is redeposited on the sample surface. In particular for rough surfaces, redeposition is expected to have a strong influence on the accuracy of the indepth analysis and on the depth resolution. To study these effects, simple model arrangements were utilized to simulate rought surfaces, which consisted of two differently inclined, adjacent planes of multilayer Cr/Ni thin films with smooth surfaces, inclined at two different angles. Depth profiling was performed by two‐point AES analysis, simultaneously on both planes, during sputtering with a rastered beam of 3 keV Ar+ ions at incidence angles of 33°, 61° and 76°. The results show that the influence of redeposition on the depth resolution of AES sputter profiles depends on the geometric position of the neighbouring planes and on the ion incidence angle.
Surface characterization by energy distribution measurements of secondary electrons and of ion‐induced electrons
Authors: Bauer H. E. , Seiler H. 
Published: May 2005

AbstractInstruments for surface microanalysis (e.g. scanning electron or ion microprobes, emission electron or ion microscopes) use the current of emitted secondary electrons or of emitted ion‐induced electrons for imaging of the analysed surface. These currents, integrating over all energies of the emitted low energy electrons, are, however, not well suited to surface analytical purposes. On the contrary, the energy distribution of these electrons is extremely surface‐sensitive with respect to shape, size, width, most probable energy, and cut‐off energy. The energy distribution measurements were performed with a cylindrical miror analyser and converted into N(E), if necessary. Presented are energy spectra of electrons released by electrons and argon ions of some contaminated and sputter cleaned metals, the change of the secondary electron energy distribution from oxidized aluminium to clean aluminium, and the change of the cut‐off energy due to work function change of oxidized aluminium, and of a silver layer on a platinum sample. The energy distribution of the secondary electrons often shows detailed structures, probably due to low‐energy Auger electrons, and is broader than the energy distribution of ion‐induced electrons of the same object point.
Quantitative surface chemical analysis of AuCu alloys with aes
Authors: Yoshihara K. , Shimizu R. , Homma T. , Tokutaka H. , Goto K. , Uemura M. , Fujita D. , Kurokawa A. , Ichimura S. , Oshima C. , Kurahashi M. , Kudo M. , Hashiguchi Y. , Fukuda Y. , Suzuki T. , Ohmura T. , Soeda F. , Tanaka K. , Tanaka A. , Sekine T. , Shiokawa Y. , Hayashi T. 
Published: May 2005

AbstractThe Japanese VAMAS‐SCA working group is composed of 19 institutes. Three kinds of Au‐Cu alloys (Au25 at%‐Cu75 at%, Au50 at%‐Cu50 at%, Au75 at%‐Cu25 at%) were prepared, and these specimens were distributed to the members of Japanese VAMAS‐SCA working group and Auger peak amplitude ratios were measured to clarify the correlation factor of different types of spectrometers. The comparison was carried out by using the relative sensitivity factor for Au and Cu. The relative sensitivity factor for lower energy varied from spectrometer to spectrometer, but that for higher energy did not vary so much. Therefore, to carry out the inter‐laboratory comparison of the data, the transfer of the data of peak amplitude at higher energy should be recommended.
Crystaline effects in single crystal and highly textured TiNxfilms
Authors: Strandberg C. , Perry A. J. 
Published: May 2005

AbstractThe results of a study of AES spectra obtained from single crystal and highly textured fine grained TiNx films are presented. The existence of specimen crystallinity effects is demonstrated particularly in the single crystal samples. These can be large enough to affect quantitative analysis. Unexpected changes in the spectra were also found on changing the incident angle of the ion beam.
Quantitative surface analysis by XPS and XAS
Authors: Ebel H. , Ebel M. F. , Krocza H. 
Published: May 2005

AbstractAs X‐ray excited Auger spectra are included in quantitative surface analysis a careful investigation of all possible excitation mechanisms must be made. For instruments with a monochromator there is only the specific characteristic radiation but instruments without a monochromator offer a wide variety of Auger excitations: white x‐radiation (target); satellites (target); O Kα (oxidized target); Cu Lα (target substrate); and Al Kα (tube window).The present paper deals with the quantification of additional X‐ray excitations of KLL‐Auger spectra from these sources. The numerical results illustrate our experimental situation. With these data it becomes possible to use X‐ray excited KLL‐Auger lines in a fundamental parameter approach for quantitative analysis.
Quantitative AES analysis of Ti silicide and Co silicide films
Authors: Chen W. D. , Bender H. , Vandervorst W. , Maes H. E. 
Published: May 2005

AbstractThe possibilities for quantitative Auger analysis in the derivative mode of Ti and Co silicide films are examined as a function of the composition. Both matrix and sputter corrections are taken into account. It is shown that the theoretical expressions for both corrections predict a weak composition dependence. However, the quantitative results obtained with this procedure strongly deviate from Rutherford backscattering spectroscopy and X‐ray diffraction measurements. It is concluded that the sputter and matrix corrections cannot sucessfully be applied for these materials. Experimental matrix and sputter correction factors are determined.
Quantitative auger electron spectroscopy of AlxGa1‐xAs layers and superstructures grown by MBE
Authors: Chen W. D. , Bender H. , Demesmaeker A. , Vandervorst W. , Maes H. E. 
Published: May 2005

AbstractQuantitative Auger electron spectroscopy analysis is performed for the ternary system AlxGa1 ‐ xAs with different x‐values. Thick layers and superstructures are grown by molecular beam epitaxy. The relative sensitivity factors are determined by the method of the internal reference element. Correction for preferential sputtering of Ga is accounted for by a correction factor determined relative to electron probe microanalysis measurements. The matrix corrections are unimportant for this system. The results will be compared with photoluminescence measurements.
Surface layers on fe formed during plasma nitriding studied by XPS and reflection EELS
Authors: Strydom I. le R. , Wells A. , Ferreira N. P. 
Published: May 2005

AbstractAnomalous compound surface layer growth is observed during plasma nitriding of ferrous materials under certain operating conditions. The formation of an iron oxy‐nitride layer by the redeposition of sputtered cathode material was found to influence the growth kinetics of the γ'‐Fe4N layer which forms during plasma nitriding of α‐Fe to the extent where the γ'‐Fe4N surface layer initially increases and subsequently decreases in thickness after deposition of the iron oxy‐nitride layer. The nature of these layers was studied by XPS and reflection EELS to elucidate the electron structure of the valence bands of these compunds. Results are Results are presented which explain the thermodynamic stability of the iron oxy‐nitride layer and the apparent de‐nitriding effect that this layer formation has on the underlying γ'‐Fe4N layer.
XPS and TRP/TPO Study of the behaviour of rhodium particles supported on TiO2
Authors: Muñoz A. , Munuera G. , Malet P. , González‐Elipe A. R. , Espinós J. P. 
Published: May 2005

AbstractOxidation/reduction processes occurring in rhodium particles supported on TiO2 have been studied by a combination of XPS and TPR/TPO. Rh(I) and Rh(III) are formed by calcination in excess of O2 at 773k, Rh(III) being favoured for samples with very small metal particles. For samples with particles in the range 2.0–10.0 nm, oxidation up to Rh2O of the whole particles occurs followed by a kinetically controlled growth of a thin Rh2O3 layer at their surface together with the formation of Rh(III) species at the particle/support interface. H2 adsorption at 300 K on the highly oxidized particles (up to Rh2O3) is an activated process which implies reduction of Rh(III) into Rh(I). Further reduction at 373 K leads to Rh(O) formation although some Rh(I) and Rh(III) species still remain unreduced up to T > 473 K. A model is proposed to decribe the evolution of these rhodium oxide particles as well as to explain their different behaviour against H2 adsorption at 300 K.
Oxygen interaction with Mo(100) studied by XPS, AES and EELS
Authors: Minni E. , Werfel F. 
Published: May 2005

AbstractThe adsorption, chemisorption and oxide formation of molecular oxygen was studied on the (100) surface of molybdenum single crystal by following the changes in Mo 3d photoelectron lines and the characteristic losses in EELS. For estimation of the oxygen content, both XPS and AES were applied. At the room temperature the oxygen content saturates rapidly resulting in a small broadening in the Mo 3d photoelectron lines. In EELS one loss line was detected sensitive to oxygen exposure. The estimated maximum coverage approaches two monolayers. When increasing the temperature and oxygen exposure the broadening of the Mo 3d lines stays quite constant but after certain temperature and exposure to oxygen the broadenings start to increase. At elevated temperatures the Mo 3d lines change to a broad band of overlapping Mo 3d lines which can be separated into individual components of Mo, MoO2 and MoO3. In EELS one bulk plasmon is split into two different structures and into an additional feature. At room temperature the chemisorbed oxygen determines the adsorption mechanism while at elevated temperatures a stepwise transition to Mo oxides seems established.
Ellipsometric studies on the interaction of oxygen with thin copper films at 460 K
Authors: Schmidt R. , Wißmann P. 
Published: May 2005

AbstractThe capability of optical measurements to elucidate adsorption as well as absorption phenomena is demonstrated by using oxygen interaction with copper films as an example. The films (thickness about 30 nm) deposited under UHV conditions on glass substrates show a polycrystalline structure with a marked (111) fibre texture. Gas doses were provided at 460 K while recording simultaneously the ellipsometric response (λ = 1152 nm) and the electrical resistivity. The optical properties of the clean films correspond to well‐known bulk data. O2 adsorption causes the ellipsometric angles σΔ and σψ to change by 0.05° and 0.02°, respectively. At pressures of about 1 Pa oxygen begins to penetrate into the interior of the sample which manifests itself in a further drastic increase of σΔ = 30° and σψ = 5°.
Study of thin corrosion films by in situ Raman spectroscopy combined with direct observation of nuclear reactions
Authors: Delichere P. , Hugot‐Le Goff A. , Joiret S. 
Published: May 2005

AbstractThe rôle played by molybdenum in the passivation and corrosion of nickel alloys has been investigated by Raman spectroscopy and nuclear reaction analysis (NRA). NRA showed that the thickness of ‘passive’ films increased with the molybdenum content. When the molybdenum content in the alloy was high (greater than 10% atom), the films were formed of nickel molybdate NiMoO4, poorly crystallized and possibly hydrated.
XPS characterization of coal surfaces: Study of aerial oxidation of brown coals
Authors: González‐Elipe A. R. , Martínez‐Alonso A. , Tascón J. M. D. 
Published: May 2005

AbstractXPS was used to determine the surface concentrations of diferent elements present in two Spanish brown coals. Sputtering with Ar+ ions followed by XPS analysis permitted depth concentration profiles in both, fresh and oxidized coals, to be obtained, and show that aerial oxidation brought about a redispersion of the organic matter onto the mineral phase. Analysis of C 1s band shape together with Fourier transform infrared (FTIR) study of organic functional groups show that loss of hydroxyl groups from the organic phase occurs by thermal decomposition during the first stages of oxidation, leading to an increase of the hydroxyl groups in the mineral phase by proton transfer. At higher temperatures, oxidation gives rise to formation of new carboxyl groups. The usefulness of XPS and some bulk characterization techniques used for studying coal oxidation is compared.
Composition and thickness of submicron metal coatings and multilayers on Si determined by EPMA
Authors: Willich P. , Obertop D. 
Published: May 2005

AbstractElectron probe micro‐analysis is applied to the determination of thin films (20–200 nm) deposited on a known substrate. Bulk standards are used for calibration and data reduction is based on the computation of Φ(pz) depth distribution functions. The Φ(pz) model of Pouchou and Pichoir and the Gaussian Φ(pz) expression of Packwood and Brown are compared by investigating Cu and Au films on various substrates. Particular refinements, mainly by introducing an effective atomic number, are discussed in respect of double layers and a large difference between the atomic number of the film(s) and that of the substrate. Mass thickness and composition of single layers as well as double layers can be determined with an accuracy of at least 5% relative. This was estimated in comparison with chemical analysis and Rutherford backscattering spectroscopy of alloys on Si applied to magneto‐optic recording.
An analytical SEM and XPS study of platinum–rhodium gauzes used in high pressure ammonia burners
Authors: Fierro J. L. G. , Palacios J. M. , Tomas F. 
Published: May 2005

AbstractScanning electron microscopy (SEM), combined with energy dispersive x‐ray analysis (EDS) and x‐ray photoelectron spectroscopy (XPS), has been used to study platinum–rhodium gauzes exposed to the conditions encountered during the oxidation of ammonia in high pressure converters. The intiial activation of gauzes in a hydrogen flame causes surface rearrangement and results in a slight Pt enrichment at the surface, while this trend is reversed in the further stages of ammonia oxidation in the reactor. Chemical analysis by both EDS and XPS techniques revealed that catalyst deactivation is caused by platinum (IV) oxide (PtO2) evaporation from the gauzes. The remainder, rhodium, is entirely oxidized to non volatile Rh2O3. The results indicate that the formation of this compound continuously stimulates platinum diffusion toward the surface.
VAMAS Surface chemical analysis standard data transfer format with skeleton decoding programs
Authors: Dench W. A. , Hazell L. B. , Seah M. P. 
Published: May 2005

AbstractIn surface analysis today many commercial instruments are operated through a computer. This computer is also used for processing the captured data, using routines from a built‐in set of options for peak synthesis, peak deconvolution, background subtraction, peak area measurement, quantification in various levels of sophistication, mapping, depth profile presentation, smoothing, differentiation and a host of other functions. However, many analysts wish to process their data on another computer in their own particular way using programs written to their specification and under their full control. They need to encode the data in the data‐capture computer into a form suitable for transmission then decode it into the form required in the receiving computer. A standard format for the transferred data would clearly lead to economies in the number of programs required to effect the encoding and decoding.To meet the above requirement, as a result of a series of iterative discussions over the last three years, first within the UKESCA Users Group and then with the VAMAS National Representatives and users and manufacturers within the VAMAS Community as well as the ASTM Committee E‐42.11, we have produced a Surface Chemical Analysis Standard Data Transfer Format defined in a standard metalanguage. This Format is intended to be used by those wishing to transfer data from computer to computer via parallel interfaces or via serial interfaces over direct wire, telephone line, local area network or other communications link. It is suitable for AES, EDX, FABMS, ISS, SIMS, SNMS, UPS, XPS, XRF and similar analytical methods. It covers elemental maps, depth profiles and sequences of data resulting from a variety of experiments. Thus the application of the Format is very general.
Simulation of electron/solid interaction and its application to quantitative analysis by Auger electron spectroscopy
Authors: Ichimura S. , Ze‐Jun Ding , Shimizu R. 
Published: May 2005

AbstractThe simulation of electron/solid interactions is discussed, with emphasis on its applicability to the matrix correction in quantitative analysis by AES, and to its potential use in background substraction in AES. The Monte Carlo calculation models are first explained, which have been improved to allow the estimation of (i) back‐scattering correction factors, and (ii) energy profiles of back‐scattered electrons in the high‐energy region (i.e. elastically‐scattered electrons and the characteristic loss structures) and the slow secondary region. For this purpose, a dielectric approach is used for the treatment of the electron inelastic scattering in the solid. Then, the models are applied to samples with bi‐layer structures, and the change of Si Auger signals observed during sputter‐etching of a sample consisting of a Si thin film (7000 Å) on a W substrate is well explained. Changes in the energy distributions of back‐scattered electrons during the formation of very thin (5 to 100 Å) Cu films on a Si substrate are also estimated by the Monte Carlo calculation, together with the shapes of the elastic peak and the characteristic loss peaks.
High mass resolution time‐of‐flight secondary ion mass spectrometry. Application to peak assignments
Authors: Niehuis E. , Van Velzen P. N. T. , Lub J. , Heller T. , Benninghoven A. 
Published: May 2005

AbstractThe negative time‐of‐flight secondary ion mass spectrometry spectrum of a trimethylsilylated silicon oxide surface and positive ion spectra of polymethylmethacrylate (PMMA) surfaces before and after treatment with an oxygen plasma are presented. The spectra were recorded with a SIMS spectrometer equipped with a Reflectron‐type mass analyser. This instrument exhibits a mass resolution high enough to be able to determine the chemical composition of the secondary ions directly from the spectra and to resolve peaks of oxygen and non‐oxygen‐containing ions with mass differences of about 0.030 amu at masses well above 200 amu.This information on the chemical composition makes it possible to determine structures of the ions originating from the surfaces, which increases insight into secondary ion formation processes. On the basis of the results from the plasma‐treated PMMA surface, a tentative mechanism is given for the interaction of an oxygen plasma with PMMA in which formation of new polymer chain‐ends containing acetyl groups plays an important role.
Methods for quantitative analysis in XPS and AES
Authors: Grant J. T. 
Published: May 2005

AbstractOne of the biggest problems in quantitative surface analysis with x‐ray photoelectron spectroscopy (XPS) or Auger electron spectroscopy (AES) is in obtaining an accurate measure for the number of photoelectrons or Auger electrons contributing to peaks in spectra. The approach taken for quantitative analysis often depends on the data acquisition method, although there are several subsequent data processing methods that can also be applied. In XPS, spectra are usually acquired by pulse counting, whereas in AES, spectra can be acquired by a variety of methods, e.g. pulse counting, voltage‐to‐frequency conversion and the use of a variety of modulation techniques. Processing methods involve peak or peak‐to‐peak height measurement, peak area measurement, background subtraction, deconvolution, differentiation, integration, spectrum addition and subtraction, curve fitting and factor analysis. The application of these techniques to quantitative analysis in XPS and AES will be reviewed.
Quantification of amorphous SiC: H films using XPS and AES with three standards
Authors: Fitzgerald A. G. , Henderson A. E. , Hicks S. E. , Moir P. A. , Storey B. E. 
Published: May 2005

AbstractQuantification has been achieved on a range of a‐SiC: H films using the techniques of XPS and AES. The procedure of quantification, involving the use of three standards, four matrix factors and an effective matrix factor, is given. These results are compared with results from standless techniques. The correlation between matrix factors, local atomic bonding configurations and the effect on the deduced composition are discussed. Recommendations are made concerning the use of various quantification methods, and their inherent errors are discussed.