bluuebunny/crossref_metadata_2025 huggingface dataset:
Theory of coupling axial and radial ion motion in an ion cyclotron resonance cell during off‐resonance excitation
Authors: Mordehai Alex V. , Henion Jack D.
Published: May 2005

An analytic theory of nonlinear effects in the Z‐oscillation (axial motion) during off‐resonance excitation is proposed. This theory is fbased on a representation of electric potential in an ion cyclotron resonance cell in the fourth‐order approximation. Z‐oscillation is considered as a parametric oscillation with a defined motion in the plane of the magnetic field. It is shown that a peculiarity of ion motion due tocoupling of axial and radial motions can be understood in terms of the stability of the Mathieu equation common to the dthree‐dimensional quadrupole ion trap (quistor). Analytic expressions relating parameters (A, Q) of the dMathieu equation to the coefficients of electric potential expansion in the cell are obtained. The strongest coupling effects arise when the frequency of excitation differs from the base cyclotron frequency bytwice the value of the effective frequency of Z‐oscillation that correof parametric resonance in Z‐oscillations.
Thermal degradation of O‐acyl oximes under electron impact ionization conditions
Authors: Horiyama Shizuyo , Suwa Kiyoko , Yamaki Masae , Kataoka Hiromi , Katagi Toyoshi , Takayama Mitsuo
Published: May 2005

Thermal degradation of O‐acyl oximes under electron impact ionization (EI) conditions has been examined. The EI mass spectra gave fragment ions originating from thermal degradation, as well as molecular ions M+· and normal fragment ions due to unimolecular decomposition of the M+· ions. The fragment ions due to thermal degradation of O‐acyl oximes were identified by using fast‐atom bombardment (FAB) mass spectrometry with a liquid matrix together with the collision‐induced dissociation (CID) technique. While the FAB mass spectra of O‐acyl oximes gave, preferentially, M+· ions together with some characteristic fragment ions, as well as the molecular related ions [M+H]+ and [M−H]+, the spectra showed little evidence of the fragment ions which may originate from thermal degradation, under EI conditions. The CID spectra of selected M+· ions formed by electron impact also showed little of such fragment ions. The thermal degradation was directly confirmed by measuring the FAB mass spectra of O‐acyl oximes that had been heated in a sealed sample tube.
Ion‐Optical solutions in time‐of‐flight mass spectrometry
Authors: Ioanoviciu Damaschin
Published: May 2005

Time‐of‐flight mass spectrometers are able to cover mass ranges to around a half a million Da. The mass resolution of these instruments has been improved drastically by incorporation of electrostatic mirrors. The ion‐optical solutions enabling these achievements and other promising features are discussed in terms of: First‐ and second‐order space focusing in time for linear drift time‐of‐flight mass spectrometers; velocity focusing by time lag; ion‐packet bunching in post‐source impulse focusing; first‐ and second‐order energy focusing in time, in single‐ and double‐stage homogeneous electrostatic mirrors with normal and oblique ion incidence; gridless designs; perfect time focusing in parabolic potential and axial symmetry; cylindrical ion mirrors and toroidal electrostatic deflectors as time‐of‐flight mass analyzers; three electrostatic sector geometry applied in secondary ion microscopy and four toroidal sector systems for tandem mass spectrometry; poloidal electrostatic sectors. Estimation of time‐of‐flight mass spectrometer performance limits is discussed and the stable as well as the metastable peak shapes found in time‐of‐flight mass spectra.
Delayed extraction matrix‐assisted laser desorption time‐of‐flight mass spectrometry
Authors: Vestal M. L. , Juhasz P. , Martin S. A.
Published: May 2005

A new delayed extraction matrix‐assisted laser desorption/ionization (MALDI) time‐of‐flight (TOF) mass spectrometer system is described which provides dramatically improved performance over that obtained with identical TOF analyzers operated with constant electrical fields. In this system the ions formed by MALDI are produced in a weak electrical field, and subsequently extracted by application of a high voltage pulse after a predetermined time delay. Three parameters can be independently adjusted to optimize the performance. These include the field magnitude and direction during and immediately following ion production, the magnitude of the extraction field, and the time delay between the laser pulse and application of the extraction field. Theoretical equations are presented which guide the selection of these parameters to optimize the performance.

Results are presented from three TOF analyzers of similar design, but ranging in size from a 1.3 m linear analyzer to a 6.4 m reflector. In all cases delayed extraction provides substantially improved resolution over that obtained from static operation. In the smallest linear analyzer resolution of M/ΔM (full width at half maximum) of 4000 is demonstrated for angiotensin I, and with the largest reflecting analyzer, the isotope peaks of bovine insulin are resolved nearly to baseline. With larger proteins, the isotopic peaks are not resolved, but resolution approaching the width of the isotopic envelope is obtained. Resolution improvement is demonstrated for proteins up to 30 kDa. In addition to improved resolution, delayed extraction is shown to improve the quality of MALDI mass spectra by suppressing matrix background, reducing chemical noise, and minimizing the effect of laser intensity on performance.
The characterization of proteins and peptides by automated methods
Authors: Bonner Ron , Shushan Bori
Published: May 2005

A suite of software programs called the BioToolBox is described. The primary purpose of the BioToolBox is to facilitate the characterisation of proteins and peptides using data acquired by IonSpraTM mass spectrometry and tandem mass spectrometry. As an example, the characterization of a 50 KDa protein (transcription termination factor‐rho) is described. The programs which comprise the BioToolBox produce complementary information which is exchanged between the software modules.
The contribution of bremsstrahlung to radiation damage by ESCA
Authors: Wagner C. D.
Published: May 2005

There has been a widely‐held belief that the radiation damage occasionally observed in analysis by ESCA is largeldue to the bremsstrahlung component of the radiation from electron impact on the aluminum or magnesium X‐ray anodes. Analysis of the distribution of photons detected from 15kV electrons on aluminum shows that no more than 3% of the radiation damage can come from the bremsstrahlung component.
On the influence of sample temperature on depth resolution in sputtering
Authors: Kühlein Maria , Jäger Ingomar
Published: May 2005

Evaporated silver layers of varying thickness on poly‐crystalline copper substrates were sputtered off at different temperatures. The relation between depth resolution and sample temperature at different layer thickness was investigated. It turned out that raising the temperature from 298 K to 423 K results in a significant improvement of Δz whereas at 498 K the depth resolution is—although better than at 298 K—poorer again. Within the investigated range of depth Δz varies like Δz ∞ z5/6 for all temperatures thus indicating a strong deviation from the SLS model.
Developing trends in the application of XPS in the USA
Authors: Wagner C. D. , Joshi A.
Published: May 2005

Some recent developments in XPS in the United States are briefly described. Two new instruments have been introduced, one a ‘Small Spot ESCA’, providing analyses of <1 mm area with monochromatized x‐rays, the other a conveniently engineered hemispherical analyser with very high data gathering speed and good resolution. Studies of energies of Auger lines along with those of photoelectron lines elucidate the role of screening energy in chemical shifts. Neighboring molecules, and especially neighboring conductive surfaces can provide screening energies of more than an electron volt. Effects on thin films and highly dispersed phases are beginning to emerge. Accurate data on energies and energy differences of shallow core levels and valence bands are providing information on band bending and chemical shifts at interfaces, information of great value in the semiconductor industry. Low energy monochromatized photons from synchrotron sources have provided data on shifts in core levels between surface atoms and bulk atoms. Applications in surface science are just beginning.
Compositional changes of ZnSe during implantation measured by SIMS and AES
Authors: Haberland D. , Krabel B. , Nelkowski H. , Schlaak W.
Published: May 2005

Using a specially designed system it is possible to observe the compositional changes of a surface during implantation. The results of implantation with Ag, Cl, Na into ZnSe will be presented. From the measured intensity of the secondary ions produced by ion implantation into the compound semiconductor ZnSe we will infer to the stoichiometric disturbance of the implanted layer. After implantation the changes can be observed quantitatively by AES, too.
Channeling effects in polycrystalline copper—a serious impediment to quantitative Auger analysis?
Authors: Doern F. E. , Kover L. , McIntyre N. S.
Published: May 2005

Variations in absolute Auger intensity of as much as 40% are reported for the analysis of polycrystalline copper surfaces in a high resolution scanning Auger microprobe. The angular dependent Auger yield is correlated with channeling effects of the incident electron beam. A correction procedure based upon ratioing the Auger peak intensity to the elastically backscattered electron peak, combined with an angular averaging technique can reduce the crystallographically induced Auger yield variations by a factor of four.
On the role of Gibbsian segregation in causing preferential sputtering
Authors: Kelly Roger
Published: May 2005

It is well known that preferential sputtering with binary alloys correlates significantly with chemical binding, but only the sense and not the magnitude of the effect can be understood in these terms. It is argued here that the correlation is, in fact, an indirect one due to bombardment‐induced Gibbsian (or similar) segregation. The preferentially removed component is characterized by a composition profile consisting of a one atom‐layer‐thick spike at the surface; this is the depth from which most sputtered atoms originated so the spike must have near‐bulk composition. There is then a severely depleted subsurface region in accordance with Gibbsian segregation equilibrium (or an equivalent effect) and a final return to bulk composition. The reason for the marked correlation with chemical binding is that segregation is governed significantly more often by binding than by the alternatives of size, surface chemistry, an interstitial flux, or long‐range ordering.
A multilayer model for GaAs oxides formed at room temperature in air as deduced from an XPS analysis
Authors: Demanet C. M. , Marais M. A.
Published: May 2005

An XPS study of the oxides formed on GaAs at ambient temperature and in ambient atmosphere is reported. Special attention has been paid to the interpretation of the Ga 3d and As 3d energy levels. By varying the angle between energy analysed electrons and the surface of the sample the depth distribution of the various oxides has been deduced. A multilayer model deduced from XPS analysis and the known reactivity of GaAs and the various oxides is proposed.
XPS study of iodine released in core melting experiments
Authors: Moers H. , Dillard J. G. , Klewe‐Nebenius H. , Kirch G. , Pfennig G. , Ache H. J.
Published: May 2005

Core melting experiments are performed in order to investigate on a laboratory scale the behaviour of the reactor core constituents released during severe light water reactor accidents in the form of aerosols and the dependence on the temperature of the melting charge. The materials used reflect the composition of a pressurized water reactor core including structural materials, fuel, and fission products. One of the most important questions regards the release and chemical behaviour of fission product iodine.

X‐ray photoelectron spectroscopy (XPS) of aerosol samples released at temperatures ranging from 1200 °C to 1900 °C revealed caesium, silver, indium, cadmium, iodine, and tellurium as constituents of the aerosol surface. The main compounds identified were: caesium hydroxide, silver metal, indium oxide, cadmium hydroxide, tellurium dioxide.

The investigation of the chemical nature of iodine was difficult because of the low iodine concentration in the samples and because of the small chemical shifts in the photoelectron energies of the possible iodine compounds. The determination of its chemical states was possible with a combination of XPS and argon ion bombardment and resulted in identification of CsI and HgI. The procedure chosen required in addition a critical reflection on the influence of ion bombardment on the surface chemistry.
Oxygen coverage effects in SIMS quantitative analysis using a primary rastered probe
Authors: Lang J. M. , Degrève F.
Published: May 2005

The surface oxygen coverage θ has a great influence on positive secondary ion yield. θ must be equal to 1 for optimum quantitative analysis. On SIMS machines (like the CAMECA IMS‐3F) using a rastered high current density probe, instead of a static defocused (hence low current density) beam, there is a danger that this condition is not achieved where bombarding the sample with Ar+ ions while blowing O2 on to the sample. A simple model of the evolution of θ under the rastered probe is proposed; it provides a good frame to interpret surprising experimental results such as: (a) the existence of transients which can last for several seconds (primary Ar+); (b) the existence of cristallographic differential sputtering even though the oxygen back pressure is high; (c) the secondary signal can decrease when the primary beam intensity is increased. An easy and quick way of detecting conditions that would lead to erroneous interpretation is proposed.
Detection of water soluble flux residues on printed wiring boards by ESCA
Authors: Roberts R. F.
Published: May 2005

The use of water soluble flux (WSF) in soldering processes of electronics manufacture is desirable from environmental, economic, and technical standpoints. However, ineffective removal of WSF residues in post‐solder cleaning procedures may give rise to electrical malfunction or failure due to the chemical activity of WSF residues on various electronic components. In the present work, electron spectroscopy for chemical analysis (ESCA) has been used to detect WSF residues in the surface region of printed wiring boards (PWBs). This has been accomplished by examining PWB samples exposed to WSF, a soldering process, and a post‐solder cleaning procedure. The successful ESCA detection of WSF residues provides a direct means of evaluating the effectiveness of post‐solder cleaning procedures used to remove undesirable WSF residues.
Soft x‐ray appearance‐potential study of Ti–Ni system
Authors: Hatwar T. K. , Chopra D.
Published: May 2005

Soft x‐ray appearance‐potential spectroscopy (SXAPS) probes the binding energies of the core levels and local unoccupied conduction‐band states of solid surfaces. This technique has been exploited to study the electronic structure of Ti–Ni alloys of atomic composition TixNi1–x where x = 0, 0.3, 0.5, 0.7, 1.0. The measured full width at half maximum (FWHM) of the Ti L3 peak systematically decreases with increasing Ni content while the Ni L3 peak shows a corresponding decrease. The binding energies of both constituents shift towards higher energy as a result of Fermi level shift and charge transfer from Ti to Ni. These measurements are in agreement with the common‐band model for these alloys.
Calibration of argon ion sputter rates using nuclear microanalysis and Auger spectroscopy
Authors: Tapping R. L. , Davidson R. D. , Jackman T. E.
Published: May 2005

Auger electron spectroscopy (AES), in conjunction with argon ion sputtering, is frequently used to obtain composition versus depth profiles. Thin film thicknesses may be estimated from such profiles if the argon ion sputtering rate of a particular material is known. For this work, a series of oxide standards was prepared and calibrated with nuclear microanalysis techniques. These standards were then used to calibrate the composition versus depth profiles obtained using AES.
Effect of temperature during ion sputtering on the surface segregation rate of antimony in an iron–antimony alloy at higher temperatures
Authors: Oku M. , Hirokawa K. , Kimura H. , Suzuki S.
Published: May 2005

The surface segregation of antimony in an iron–0.23 at% antimony alloy was studied by XPS. The segregation rate in the temperature range between 800 and 900 K depends on the temperature during sputtering with argon ion of kinetic energy of 1 keV. The sputtering at room temperature or 473 K gives higher values of the segregation rate than those at 673 K. Both cases give the activation energy of 170 kJmol−1 for the surface segregation rate. The segregation of antimony is not observed after the sample is heated at 1000 K.
Use of oxygen Auger line relative intensities for characterization of surface oxides on oxidized metals and alloys
Authors: Laudet A. , Jardinier‐Offergeld M. , Bouillon F.
Published: May 2005

Exemplifying results from AES study of high temperature oxidation of dilute copper‐aluminium alloys, under low pressures of oxygen, are presented to demonstrate the feasibility of using changes in relative intensities of oxygen Auger lines as a diagnostic test for oxidation selectivity, at the very early stages of the reaction.
Determination of depth resolution from measured sputtering profiles of multilayer structures: Equations and approximations
Authors: Hofmann S.
Published: May 2005

Equations to extract the depth resolution from measured sputtering profiles of multilayer structures are presented. The range of application and the errors involved are discussed with respect to the ratio between depth resolution and layer thickness.
Computer graphics display of 3‐D analysis data
Authors: Watson S. G. , Millham C. B. , Lewis K. , Stulik D.
Published: May 2005

The development of a computer program to display results of 3‐D analysis is described and discussed. The program can data in the desired format, display a representation of a 3‐D grid in the recent version limited to 10 × 10 × 10 divisions, and fill the grid with colors and shades representing different chemical elements and their concentration. To allow a detailed inspection of the analyzed volume from different viewing angles, the whole 3‐D scene can be rotated to any desired position. To allow inspection of the interior of the analyzed volume, the display can be cross‐sectioned or scanned through in various directions. Capabilities and limitations of the program as well as unresolved problems and suggestions for its future development are presented. The program is tested using a model data file representing a simplified 3‐D microelectronic circuit and a complex shape inclusion in the matrix material.
Surface investigation, by XPS, ISS and IR spectroscopy of adsorbed NO, of the structural changes occurring during the reduction of Co‐Mo/γAl2O3 catalysts
Authors: Prada Silvy R. , Fierro J. L. G. , Delmon B. , Beuken J. M. , Bertrand P.
Published: May 2005

The structural changes produced during the reduction by H2 at different temperatures (300–800°C range) of a commercial Co‐Mo/γAl2O3 hydrodesulphurization catalyst have been investigated by x‐ray photoelectron spectroscopy (XPS), ion scattering spectroscopy (ISS) and infrared (IR) of absorbed NO, as a probe‐molecule. In all samples, different cobalt phases are observed. A fraction of cobalt interacts with the alumina support (CoAl2O4‐like, species which was reducible only at the highest temperatures) and another fraction forms a phase interacting with the molybdenum atoms (species easily reducible at moderate temperatures). XPS and ISS results indicated that, at reduction temperatures above 600°C, several effects are produced: (a) an increase of metallic cobalt, (b) a decrease of CoAl2O4 concentration and simultaneous crystallization of MoO2 species, and (c) a decrease of the molybdenum dispersion. From the IR spectra of NO probe chemisorbed on reduced catalyst at 800°C, it was concluded that the slight increase of the Co0 exposure could be due to reduction of CoAl2O4‐like species.
Structural and compositional studies of sputtered nickel ferrite films
Authors: Fitzgerald A. G. , Muir G.
Published: May 2005

The crystal structure, composition and surface composition of sputtered nickel ferrite films have been studied. The films have been prepared by sputtering in argon and reactively sputtering in oxygen from a nickel ferrite cathode and from an invar alloy cathode. Nickel ferrite has been identified as the main constituent of these films. XPS and AES have been used to study the surface composition of these sputtered films and NiFe2O4 and oxides and hydroxides of nickel and iron have been identified on the surface. Only films sputtered in argon from a nickel ferrite cathode were found to have the exact nickel ferrite composition. The deposition of these films onto single crystal MgO, a suitable substrate for epitaxial growth, has also been studied. AES results after annealing at 1000 °C indicate that for thin films, nickel and iron diffuse into the MgO substrate.
Quantitative surface analysis by glow discharge optical spectrometry
Authors: Pons‐Corbeau J. , Cazet J. P. , Moreau J. P. , Berneron R. , Charbonnier J. C.
Published: May 2005

In an analysis by glow discharge optical spectrometry the relation between the intensity of an optical emission line of an element and its concentration on the surface is exploited for quantitative determination of variations of composition in galvanized coatings and for an estimation of the enrichments on the surface of annealed extra mild steel sheets.
The application of laser ionization mass spectrometry to the study of thin films and near‐surface layers
Authors: Clarke N S , Ruckman J C , Davey A R
Published: May 2005

The laser ionization mass analyser, LIMA, was originally developed as a bulk microprobe instrument giving elemental information similar to that obtained from the conventional electron probe microanalyser, but with the advantage of full periodic table coverage. The LIMA is therefore capable of detecting all elements including hydrogen, helium, lithium, and beryllium, which are inaccessible to EPMA. Other advantages of LIMA over EPMA are isotope discrimination and the ability to obtain chemical information from materials as a result of the emission of complex ionic fragments from surfaces under laser irradiation. As experience grew with the use of the prototype LIMA at Aldermaston, it became clear that the technique was a particularly versatile tool which could not only perform well as a bulk microprobe, but with suitable experimental procedures could also be used as a sensitive depth profiling instrument with moderate depth resolution (≥0.01 μm). It became apparent that in its performance parameters, and in many of its applications in bulk and surface analysis, LIMA was directly comparable with dynamic SIMS. This paper is, therefore, concerned with the applications of LIMA when operated in a surface sensitive mode. In general, this involves using low power densities, and a defocused laser—the defocusing means that some sacrifice in lateral resolution must be made. Nonetheless, it is shown in this paper that the LIMA has a genuine contribution to make in depth profiling and thin film analysis.
Surface chemical analysis—report on the vamas project
Authors: Powell C. J. , Seah M. P.
Published: May 2005

The VAMAS project on surface chemical analysis is a multi‐national cooperation for the provision of standards data and materials for surface chemical analysis measurement and for the provision of the basic understanding necessary for these activities. This project is one of a rapidly growing suite of projects initiated as a result of decisions following the 1982 Versailles Summit Meeting of the Heads of State or Government of Canada, France, Germany, Italy, Japan, UK, USA and the representatives of the Commission of the European Communities. During the past year national representatives to this VAMAS project have been appointed and national committees established. This article summarizes the philosophy, scope, and organization of the project and describes specific activities that have been initiated. Information is given on how individuals, both within and outside the group of member states, may participate.
Prediction of auger backscattering factors from measurements of spectral backgrounds
Authors: Prutton M. , El Gomati M. M.
Published: May 2005

The shape of N(E) has been obtained from a carefully characterized electron spectrometer for 24 different elements and compounds. The secondary electron cascade has been found to obey a form N(E) = AE−m. A and m have been measured and used together with a model of the energy distribution of rediffused primary electrons to calculate an Auger backscattering factor for each material when the primary energy is 20 keV. These calculations have been compared with backscattering coefficients measured at the carbon 1s binding energy in the same instrument on the same samples. The results show the backscattering factor to be linear in atomic number. The measurement of A and m from a spectrum can be used to estimate the backscattering factor within an estimated error of about ±0.05.
Surface segregation in Fe‐18Cr‐3Mo single crystal
Authors: Schiffman B. , Polak M.
Published: May 2005

The (100) surface region of the Fe‐18Cr‐3Mo ternary alloy was investigated during and after argon sputtering at ambient and elevated temperatures by means of Auger electron spectroscopy. Low and high‐energy lines, corresponding to different sampling depths, were monitored, and the quantitative analysis was based on relative intensities from an in situ scribed crystal, representing the bulk composition. The Cr:Fe steady‐state ratio measured during sputtering reflected significant subsurface Fe depletion which reached a maximum at ∼800 K and then decreased. This trend could be inverted (i.e. inducing Cr depletion) by Ar sputtering under some residual CO. Similarly, compositional changes observed after sputtering were critically dependent on the cleanliness of the surface. The results are discussed in terms of possible (Gibbsian) surface segregation of Fe vs. chemically‐induced segregation of Cr and Mo.
Analysis by scanning electron microscopy and structure determination by high resolution electron microscopy of ni/ni3b eutectic
Authors: Desseaux‐Thibault J. , Hamar‐Thibault S.
Published: May 2005

The eutectic Ni/Ni3B has been found in a number of special hardfacing alloys such as Ni‐Cr‐B‐Si. However, this eutectic has not been studied. This eutectic is a good model. Ni3B has the same crystallographic structure as Fe3C. The combination of HREM with EDX and EELS is a means to obtain together data on composition and morphology of defects and grain boundaries. Here an attempt is made to determine the structure by HREM and to analyse by EELS both Ni and Ni3B. Images of low indexed planes of Ni3B are obtained and interface observed.
Surface analysis and the complexity of real catalysts
Authors: Delmon Bernard
Published: May 2005

This paper is written for specialists of surface techniques not perfectly familiar with catalysis, as well as for scientists working in the area of heterogeneous catalysis. It is aimed at suggesting the problems of characterization that surface analysis is faced with, because of the complexity of real catalysts. We first present the various typical ‘architectures’ to which catalysts may correspond. We shall then illustrate typical problems, and their solutions, by selecting examples in the field of hydrodesulfurization (HDS) catalysts. We shall show how 10 out of the 12 theories proposed for explaining catalytic activity were eliminated thanks to surface techniques. HDS catalysts are remarkable in several respects, especially because they undergo many ‘metamorphoses’ (activation, modifications during catalytic work, ageing, regeneration) from the time of their preparation to that of their death by irreversible deactivation. They therefore provide a large body of illustrative examples concerning the characterization of several ‘architectures’. In spite of the achievements of surface techniques in clarifying many features of HDS catalysts during their life, investigators are still faced with unsolved problems; many such problems are related to the very fine scale (of the order of 1 nm or less) of the details of importance for catalysis. This might suggest directions for new improvements or the development of new surface techniques. As a conclusion, we shall recall that, because complete characterization needs the joint use of several techniques, a methodology of study had to be developed, now exists, and still continues to improve. The main lines of this general methodology are not restricted to catalysts, but can be used for the study of all complex highly dispersed solids.
Characterization of supported bimetallic FeIr/SiO2 catalysts by mössbauer spectroscopy, temperature‐programmed reduction and X‐ray photoelectron spectroscopy
Authors: Niemantsverdriet J. W. , van der Kraan A. M.
Published: May 2005

Supported bimetallic FeIr/SiO2 catalyst have been chacterized by in situ Mössbauer spectroscopy, temperature‐programmed reduction (TPR) and XPS. The reduction of iron in freshly prepared FeIr/SiO2 catalysts is greatly facilitated by the noble metal iridium. Reduced catalysts consist of Ir‐rich fcc FeIr alloys, possibly some isolated Ir metal, and significant amounts of iron (III) oxide. The Mössbauer parameters of the latter change when the catalyst is exposed to CO gas at room temperature, indicating that the iron (III) oxide is present in a highly dispersed phase. Evacuation of reduced samples at 475 or at 775 K leads to significant oxidation of the iron in the catalyst, most likely by OH groups on the SiO2 support.
Perspectives in surface and interface analysis for electronic devices and circuits
Authors: Heckingbottom R.
Published: May 2005

Over the past two decades a variety of techniques have been developed for the analysis of surfaces and interfaces. Despite the multiplicity of interfaces in electronic devices however, and the need for precise control, surprisingly few of these techniques have had a major impact in the area. Scientific successes such as low energy electron diffraction (LEED) find little application, and a straightforward comparison of the strenths and weaknesses of Auger electron spectroscopy (AES) and x‐ray photo‐electron spectroscophy (XPS) gives little indication of the massive preference for the former in analysing devices and circuits. A similar disparity in usage has also arisen between dynamic and static SIMS, only the former being significant. It is also clear that several of the more important techniques can be used to analyse thin films as well as surfaces and interfaces. Further, that the techniques are often more quantitative in their application to films. Again it is surprising how little pressure there has been to minimise the shortcomings with respect to interface analysis.

With the benefit of hindsight, some of the features that have led to certain techniques becoming particularly useful in application will be considered. Some new trends in device and circuit research which may increase the emphasis on surface and interface analysis will be identified. In this new area the growing importance of techniques such as transmission electron microscopy, not automatically included as a leading surface and interface analysis technique, will be illustrated.
A characterization study of the native Oxide layer formed on chemically Etched InP (111)
Authors: Hoflund Gar B. , Corallo Cheryl F.
Published: May 2005

ISS, AES and angle‐resolved ESCA have been used to characterize the native oxide layer formed on the chemically polished and etched InP (111) surface. It is estimated that this oxide layer is about 30 Å thick and forms a sharp interface at the oxide/InP boundary. The oxide layer is nonhomogeneous. ISS shows that the outermost surface layer is In rich, and AES combined with the ISS results shows that the region just below the surface layer is P rich. The In is believed to be present in the oxide layer as InP and InPO3 in approximately equal concentrations. Only a small amount of In2O3 is detected. Carbon also comprises the oxide layer, and ESCA shows that it is present as graphite and/or hydrocarbons. The region below the oxide layer is P rich, but depth profiling using AES while sputtering suggests that the composition may approach that of InP with increasing depth.
Depth resolution improvement in AES sputter profiling of Ni/Cr multilayers on rough substrates using two ion beams
Authors: Hofmann S. , Zalar A.
Published: May 2005

Three point depth profiling by scanning Auger microscopy and simultaneous sputtering with one ion beam and subsequent addition of a second ion beam, incident from a different direction, is applied to multilayer Ni/Cr structures deposited on a rough (roughness Ra = 2.3 μm) silicon substrate. Depending on the analysed microarea of about 1 μm diameter, depth resolutions between 25 nm and 44 nm at 125 nm sputtered depth were obtained using one ion beam. The extent of the improvement in Δz after sputtering with two ion beams is directly related to the absolute values obtained in each of the three microareas. The results are explained in terms of shadowing and redeposition effects which are diminished by the use of sputtering with two ion guns.
Auger analysis of metal matrix–ceramic fiber composites
Authors: Sherman Robert
Published: May 2005

The mechanical behavior of composite systems is related to the properties and relative contents of their constituents. In certain systems the reaction zone (the interface region between the metal matrix and the ceramic fiber) can have a major role in determining the overall mechanical response of composites. For magnesium and magnesium alloy (ZE41A) metal matrix–aluminum oxide fiber composites, an analysis using Auger spectroscopy of the reaction zone indicated that complex chemical reactions occur during processing and that reaction zone chemistry and structure are important variables in determining the overall mechanical response. The results of the Auger analysis are discussed and compared with other surface analysis studies performed on the same composite system.
Scanning Auger measurements of nickel coated carbon fibers
Authors: Brinen J. S.
Published: May 2005

Scanning Auger microscopy (SAM) was used to study the chemistry of the interfacial region of nickel coated carbon fibers. The interface is exposed by either in situ fracture or by sputtering with Argon ions. From the fracture experiments it was found that the carbon content on the interior nickel wall is double the carbon content in the bulk nickel suggesting the nickel–carbon interface is stronger than the forces holding the carbon fiber together.
Comparison of Auger and SIMS analysis of a thin passive oxide film on iron—25% chromium
Authors: Mitchell D. F. , Graham M. J.
Published: May 2005

A comparison of three surface‐analytical methods, viz: variable escape angle Auger electron spectroscopy, Auger sputter profiling and SIMS sputter profiling, is presented for a 1.8 nm‐thick ‘passive’ oxide film on Fe–25% Cr alloy. The three techniques give identical results regarding the composition of the film as a function of depth. This means that with the proper choice of sputtering conditions (heavy ions of low energy), sputter mixing and sputter reduction are not a problem. It is evident from the experimental data that SIMS sputter profiling has the best depth resolution of the three techniques for such a thin film.
Breakdown voltage and surface compositon in a lead borosilicate glass
Authors: Vasquez Patrizia , Puglisi Orazio , Licciardello Antonino , Arnold George W. , Patti Alfonso , Pignataro Salvatore
Published: May 2005

The breakdown voltage of a lead borosilicate glass used to passivate ‘mesa’‐channels in silicon chips is considerably lowered by the chemical treatments required by the fabrication flow chart. Surface analysis and near‐surface analysis of the glass samples shows that the chemical etching depletes both surface and near‐surface regions of the glass of Al, B and Pb. Contemporaneously the glass surface becomes O‐ and H‐rich with respect to the untreated samples. This is consistent with a mechanism based upon the formation of a silanol‐rich surface which lowers the breakdown voltage.
Ion bombardment effects in the sputtering of single‐ and two‐phase brass alloys; Cu: 18–48% Zn
Authors: Hammer G. E. , Shemenski R. M.
Published: May 2005

The effect of ion bombardment on the near‐surface composition of brass has been investigated over a bulk composition range including single‐phase α (fcc) brass and two‐phase, α + β (bcc) brass. Auger electron spectroscopy has been used to determine the equilibrium near‐surface composition after ion sputtering with argon and xenon at ion energies between 1 and 4 keV. Preferential removal of the zinc was found under all conditions. X‐ray photoelectron spectroscopy has been used to investigate variations in composition in the first atomic layers by comparison of the intensities and escape depths of the 2p and 3p photoemission peaks. The near‐surface composition was primarily a function of ion energy in the single α phase, with higher ion energy increasing the preferential removal of zinc; no change was detected comparing data from information depths of 5 vs. 10 monolayers. In the mixed α + β phase, surface zinc concentration decreased with increasing ion energy and mass, and depletion of zinc was greater nearer to the surface.
Investigation of the sampling volume in secondary ion microanalysis III. Peculiarities of multi‐element metal specimens under oxygen bombardment
Authors: Mai H.
Published: May 2005

The modification caused by oxygen primary ion bombardment in homogeneous multi‐element metal specimens has been studied. Investigations of the appropriate sample region of Fe40Ni40P14B6 and Fe81Si3.5C2B13.5 metallic glasses by transmission electron microscopy, electron diffraction and scanning Auger microanalysis revealed an inhomogeneous steady‐state sampling volume. Chemical decomposition of the initial matrix, precipitation of oxide components and formation of crystalline phases have been proven.
Auger signal‐to‐background ratio for incident beam voltages ranging from 30 keV up to 100 keV
Authors: Chazelas J. , Friederich A. , Cazaux J.
Published: May 2005

The Auger spectra of silver, copper, gold, SiO2 and GaAs have been obtained, for the first time, by using incident beam energies E0 ranging from 30–100 keV. It is found that the signal‐to‐background ratio always increases when E0 is increased, while the signal‐to‐noise ratio slightly decreases. Some consequences related to the use of high primary beam energies in AES are suggested.
Quantifying the effects of uneven etching during the SIMS analysis of periodic doping structures grown by silicon MBE
Authors: McPhail D. S. , Dowsett M. G. , Fox H. , Houghton R. , Leong W. Y. , Parker E. H. C. , Patel G. K.
Published: May 2005

Problems associated with the secondary ion mass spectrometry (SIMS) depth profiling of periodic doping structures are discussed with reference to experiments on a boron‐in‐silicon modulation doping structure and a boron‐antimony silicon super‐lattice, both grown by silicon molecular beam epitaxy (MBE). The effects of uneven etching during SIMS analysis are compared with the effects of dopant diffusion during growth. Uneven etching is modelled with an algorithm in which the macrotopography of the crater base is described in terms of an unevenness function f(x, y). Simulation depth profiles involve passing craters of this topography f(x, y) through specified, laterally homogeneous, doping distributions ρp(z) in a series of equal depth interations. The predicted SIMS signal is proportional to the amount of dopant sputtered per depth iteration. The model explains the peak shapes and the loss of depth resolution with depth that are observed experimentally. The effects of dopant diffusion during growth are found by re‐heating parts of the wafer to the growth temperature for various periods of time and then SIMS depth profiling them (thermal cycling).
Investigation of solidsolid surface adsorption of Eu2O3 on η‐Al2O3 and SiO2 gel
Authors: Rongchuan Liu , Yuanfu Hsia , Engelmann H. , Jing J.‐F. , Huali Jiang , Gonser U. , Krämer N.
Published: May 2005

The dispersity of Eu2O3 on the surfaces of Al2O3 and SiO2 gel have been studied by Mössbauer spectroscopy and x‐ray diffraction analysis. The Mössbauer data allow some insight into the structure of the dispersed Eu2O3 for both carriers. X‐ray and Mössbauer data indicate that the surface adsorption of Eu2O3 on Al2O3 is different from that on SiO2.
Identification of positive secondary ions in static sims spectra of poly(methylmethacrylate) using the deuterated polymer
Authors: Brinkhuis R. H. G. , van Ooij W. J.
Published: May 2005

Positive static SIMS spectra of poly(methylmethacrylate) (PMMA) and perdeuterated PMMA have been compared. The usefulness of this approach for the distinction between hydrocarbon and oxygen‐containing secondary ions is demonstrated. For example, a major characteristic fragment like the one at 69 amu, which had been tentatively identified as C5H9+ by other authors, was shown to be C4H5O+.
Characterization of copper/enamel interfacial reactions during aging
Authors: Burrell Michael C. , Keane John J.
Published: May 2005

The interfacial reactions occurring between copper surfaces and a polyesterimide enamel coating during aging at 200°C have been investigated using XPS, AES and SEM. For coating thicknesses of 0.1 μm or greater, a copper oxide layer grows on the copper surface beneath the coating as a result of a reaction with oxygen from the atmosphere. In addition, copper becomes detectable with aging at the air/polyesterimide interface and in the bulk of the coating by surface analysis methods, indicating formation of a mobile copper species. Changes in the XPS line components indicate changes in the polyesterimide structure have occurred. Samples with very thin coatings (c. 100 Å) were also prepared and aged in an attempt to create an interface with dimensions approaching the XPS sampling depth. Upon aging, however, copper oxide grew on top of the original coating, rather than beneath it as in the case of the thicker coatings.
Transient effects during SIMS depth profiling with oxygen
Authors: Avau D. , Vandervorst W. , Maes H. E.
Published: May 2005

Before a steady state is reached in a SIMS experiment with oxygen primary ions, transient effects occur due to the build‐up of an oxygen profile in the sample. We studied profiles in the situation in which the variation of ionization yield, radiation enhanced diffusion, and radiation enhanced segregation are assumed to be the relevant processes. Low energy As and Sb implantations (4 keV to 10 keV) as well as homogeneously doped wafers are studied. In the transient region attention is paid to the As or Sb ion as well as to a high intensity molecular compound (AsSiO or SbSiO). Experiments are carried out using an electron beam to irradiate the sample during sputter profiling. The changes in the profile shape with varying primary energy, oxygen partial pressure and electron beam impact conditions lead to the description of a model of the enhanced redistribution due to segregation. This model includes the possibility for segregation towards the surface at the internally formed SiO2 layer.
Solid‐state diffusion and point defect studies evaluated by SIMS
Authors: Södervall U. , Lodding A. , Odelius H.
Published: May 2005

The applicability of secondary ion mass spectrometry to tracer diffusion study in different solids has been tested. The diffusion of B and Ge has been measured in Si single crystals under different hydrostatic pressures. The isotope effect of diffusion at different temperatures has been determined for tri‐ and tetra‐valent impurities in single‐crystal Cu and Ag.

The activation volumes in Si appear non‐zero or negative, in line with an interstitial type of diffusion mechanism. The isotope effect E for Ga and Ge in Cu, and for Sn in Ag, obtained by SIMS with accuracies competitive to the best radiotracer measurements, are lower than for self‐diffusion in the noble metals, in line with simple theory based on monovacancies. Near to the melting point, E increases with temperature, which is contrary to the divacancy‐attributed tendencies reported for the isotope effect of self‐diffusion in Group 1B metals. The presently observed behaviour of polyvalent impurities at high temperatures, nevertheless, does not appear easily reconcilable with only a single vacancy diffusion mechanism.
Round Robin on combined electrochemical and AES/ESCA characterization of the passive films on FeCr and FeCrMo alloys
Authors: Marcus P. , Olefjord I.
Published: May 2005

A Round Robin has been organized by the Working Party of the European Federation of Corrosion on Surface Science and the Mechanisms of Corrosion and Protection.1 Ten European laboratories participated in this Round Robin.2 The aim was to compare the results obtained by AES and ESCA analyses of passive films formed on FeCr and FeCrMo alloys in 0.5 M H2SO4. All participating laboratories followed a standard procedure that had been previously established by the Working Party. The recommended procedure defines the conditions for the surface preparation, the electrochemical treatment, and the surface analyses by AES and ESCA.

The following aspects have been investigated.

—Polarization curves of FeCr and FeCrMo alloys exposed in 0.5 M H2SO4. Comparison of the corrosion potentials, passivation peak currents and potentials, currents in the passive region.

—Thickness of the passive films determined by AES depth profiling and by ESCA analysis.

—Composition of the films.

—Chemical states of the elements in the films, binding energies and the chemical shifts measured by ESCA.
High spatial resolution analytical electron microscopy studies on the Co/CeO2 system
Authors: Colliex C. , Ugarte D. , Wang Z. L. , Gasgnier M. , Paul‐Boncour V.
Published: May 2005

Anaytical electron microscopy (AEM) consists of extending the information generally delivered by the electron microscope (topography, structure) with a knowledge of the chemical and electronic properties. Its major advantage is to perform higly sensitive spectroscopies, such as electron energy loss spectroscopy (EELS), on nanovolumes of materials defined and localized within their environment. It is therfore well suited to the study of complex specimens, such as catalytical products, in which there is a competion of bulk and surface properties. Metallic Co particles on supporting CeO2 layers provide an illustrative example of AEM capabilities. Atomic resolution images of surfaces and interfaces are associated with EELS spectroscopy and EELS maps to obtain a detailed view of the local arrangement of the different components, at successive steps of the chemical reaction. Nevertheless, beaminduced chemical tranformations of the system have been observed at the atomic scale. Radiation damage therefore constitutes the final limitation.