bluuebunny/crossref_metadata_2025_split huggingface dataset:
A SIMS calibration exercise using multi‐element (Cr, Fe and Zn) implanted GaAs
Authors: Clegg J. B. , Gale I. G. , Blackmore G. , Dowsett M. G. , McPhail D. S. , Spiller G. D. T. , Sykes D. E. 
Published: May 2005

AbstractMulti‐element (52Cr, 56Fe and 66Zn) implanted GaAs samples have been prepared specially for SIMS calibration. Absolute chemical measurements gave retained ion doses which agreed to within 12% of the nominal implanted dose (2.0 × 1014 atoms cm−2). Comparative SIMS depth profiles with five instruments gave Cr mode depth data which showed a variability of 5%. After data normalization to a common mode depth (168 nm) the shape of all profiles showed good agreement. SIMS anàlysis of similar samples containing lower dose implants (1.0 × 1013 atoms cm−2) showed that ∼50% of the Cr was contained in the near surface region (0–0.03 μm). This surface peak was not observed in profiles of samples which had been singly implanted with Cr. It is proposed that the Cr surface peak results from radiation enhanced out‐diffusion initiated by the subsequent Fe implant. Whilst the high dose multi‐implant samples showed a similar Cr surface accumulation, its magnitude in relation to the ion implanted dose, was smaller. These samples therefore form reliable calibration specimens for the simultaneous determination of the secondary ion responses of Cr, Fe and Zn in GaAs.
The energy dependence of electron inelastic mean free paths
Authors: Powell C. J. 
Published: May 2005

AbstractAn analysis has been made of the dependence on electron energy of calculated inelastic mean free paths (IMFPs) for aluminum, copper, silver, and gold from four recent sources of data. The analysis was made using Fano plots which clearly show differences in energy dependences. In addition, the slopes of linear regions in the Fano plots can be compared with values calculated from experimental optical data and with values obtained from Fano plots made with experimental attenuation length (AL) data. It was found that the slopes of the Fano plots using IMFPs from calculations of Powell and Penn agreed well with the optical results; there was generally good agreement for the IMFPs of Ashley et al., but the slopes using the IMFP data of Szajman et al. exceeded the optical values by 9–40%. The slopes in the Fano plots using AL data for Al, Cu, and Au exceeded the optical values by 29–54 %; this result is similar to those found in other analyses and indicates that the electron energies for these AL measurements were not high enough to be in the asymptotic Bethe region. Analysis of the optical data also showed that a lower limit for the electron energy range over which the Fano plots could be expected to be linear (with their asymptotic slopes) was about 400 eV for Al and about 1000 eV for Cu, Ag, and Au. More extensive AL measurements over a wide electron energy range are needed to determine the shapes of the Fano plots for different types of materials.
The inelastic mean free paths of electrons in semiconducting III–V compounds
Authors: Kwei C. M. , Chen L. W. 
Published: May 2005

AbstractThe inelastic mean free path of electrons in solids is an important parameter in surface studies using AES and XPS. In this paper we present theoretical calculations of this parameter for the semiconducting III‐V compounds GaAs, GaSb, GaP, InSb and InAs. These calculations are based on a model dielectric function for the response of the valence band and the local‐plasma‐approximation for the response of inner shells. In the former case, the Kramers–Kronig relation and the partial sum rule for valence electrons are applied. In the latter case, the electron density distribution obtained from the Hartree–Slater model is utilized. Results are compared to other calculations using the Penn's model and the model of Ashley et al. for GaAs. Since no data on experimental electron attenuation lengths in the important semiconducting III–V compounds are available, it is suggested that direct calculations of the present type are useful in applications.
Concept of an imaging XPS system
Authors: Seah M. P. , Smith G. C. 
Published: May 2005

AbstractThe concept of an imaging XPS system is analysed and the various approaches discussed. For instrument and design flexibility it is shown that a standard XPS system with an efficient input lens can be used to form a virtual image of the spectrometer input aperture on the sample surface. This defined area of analysis may be rastered across the sample surface using a pre‐lens scanning deflector system. In this way good XPS images of 256 × 256 pixels and of 250 μm resolution over an area of diameter 10 mm may be formed in ten minutes. Examples are provided from components for the electronics assembly industry demonstrating that insulators cause no problems. Design considerations are then detailed for optimizing imaging XPS systems at 25 μm and 10 μm spatial resolution involving pre‐lens scanning systems and position‐sensitive detectors.
The spectral background in electron excited Auger electron spectroscopy
Authors: Matthew J. A. D. , Prutton M. , El Gomati M. M. , Peacock D. C. 
Published: May 2005

AbstractThe power law form of the secondary electron cascade from electron bombarded solids first suggested by Sickafus is explored both theoretically and experimentally. Backgrounds of the form AE−m are shown to result from a range of different theoretical models of the electron‐solid interaction in which generation of fast secondaries by electron Compton scattering and transport to the surface are treated separately. The precise value of the exponent m is seen to depend upon the balance between elastic scattering strength and the energy dependence of the inelastic mean free path.The experimental results for eight different samples with atomic numbers between 6 and 78 are reported. The constant A appears to be related to the number density of valence band electrons. The values of m fall within the range predicted by the theoretical arguments. The generality of the form AE−m to many materials is useful for the estimation of both the Auger back‐scattering co‐efficient and the energy dependence of the inelastic mean free path from measurement of the parameters A and m.
A new method of spectra acquisition and exact mass determination of resolved peaks in high mass resolution ion microscopy
Authors: Thorne N. A. , Degrève F. 
Published: May 2005

AbstractA major problem in high resolution mass spectrometry of solid materials has been the difficulty or even the impossibility associated with identifying the resolved peaks, i.e. the determination of their exact mass. A method of exact mass determination (relative precision in the range of 10−5) of resolved peaks is presented which requires no foreknowledge of the specimen. The method is derived from mass spectrometry techniques commonly employed for the analysis of liquid or gaseous organic samples, and is based on three steps: (1) the use of an external reference sample; (2) sequential analysis of the reference and unknown sample; and (3) superposition of the two spectra. The technique is illustrated using a standard CAMECA IMS 3f ion microscope.A further advance has been the development of single ion sensitive mass spectrography, where the entire spectrum within a narrow mass range is simultaneously viewed in real time. Spectra acquisition times are reduced by a factor of up to ten. Mass spectrography allows the detection of transient peaks or peaks of rapidly varying intensity, e.g. thin surface films or oxides. Using an image processor the spectra may be integrated or averaged in real time before storing in memory. Real time spectra acquisition and interpretation make high mass resolution SIMS (indispensable in material science) a routine operation providing information otherwise difficult or impossible to obtain.
Analysis of polymer surfaces by SIMS. 12. On the fragmentation of acrylic and methacrylic homopolymers and the interpretation of their positive and negative ion spectra
Authors: Hearn M. J. , Briggs D. 
Published: May 2005

AbstractThe positive and negative ion spectra from homologous series of alkyl methacrylate, hydroxyalkyl methacrylate and alkyl acrylate polymers; poly (methacrylic acid) and poly(methacrylic anhydride) are reported. A systematic interpretation of the spectra can be accomplished on the basis of fragmentation pathways consistent with the known effects of other ionizing radiations. The negative ion spectra, previously little studied, are a powerful probe of structure for this class of polymer.
The influence of oxygen on the thermal mixing of Cr and GdxOy thin films
Authors: Shanker Kartik , MacDonald Jack R. , Chan T. C. 
Published: May 2005

AbstractThin films of Cr and Gd oxide were sequentially deposited on Kapton H polyimide and heat treated in vacuum or air at 550–673 K. The interactions between the layers was followed with Auger electron spectroscopy and Rutherford back‐scattering spectrometry. Heating caused the Cr oxide thickness to grow as a function of thermal exposure. No intermixing occurred between the Cr and GdxOy layers until the presence of O in the Cr layer near the interface. Rapid diffusion of Cr oxide into the Gd oxide layer then occurred. The Gd/O Auger signal ratio increased on heating when the Cr film thickness was small, but remained unaffected with thicker Cr films. There was no diffusion of Gd into the Cr overlayer. Diffusion of GdxOy into the polyimide was observed. A thin Cr underlayer acted as a barrier to such diffusion, but possibly only till its oxidation. Irrespective of the compositional changes, heating increased the tensile stress of the films; they also showed a greater susceptibility to tearing. The films became progressively darker, eventually turning chocolate brown. They retained their metallic lustre much longer, until the oxidation of the Cr film.
Ion bombardment effects on the near‐surface composition during sputter profiling
Authors: Lam N. Q. 
Published: May 2005

AbstractThe alteration of the near‐surface composition that has often been observed in ion bombarded alloys and compounds results from the dynamic interplay of several processes. In addition to displacement mixing leading to a randomization of atomic locations, which is dominant at relatively low temperatures, and preferential loss of alloying elements by sputtering, many thermally‐activated processes, including radiation‐enhanced diffusion, radiation‐induced segregation and Gibbsian adsorption, also play important roles. The relative significance of each process in the evolution of the sputtered flux composition and of the compositional profile of the target depends on the type of alloys, temperature and ion characteristics. Although a good semi‐quantitative understanding already exists for most of the individual processes, the number of systematic investigations of alloy sputtering that consider all of these processes and their potential interactions is still rather limited. A fundamental understanding of the synergistic effects of these processes is, however, essential for quantitative analysis of multicomponent‐material surfaces, since sputtering is routinely applied in conjunction with various analytical techniques to depth‐profile the composition. The purpose of this paper is to characterize the processes in simple physical terms and to point out under what conditions they may become important for compositional changes in near‐surface regions of sputtered alloys, based on selected results of recent model calculations and experimental studies.
Simulation of the LMM auger spectra of copper
Authors: Dubot P. , Jousset D. , Pinet V. , Pellerin F. , Langeron J. P. 
Published: May 2005

AbstractQuantitative Auger analysis is much more difficult to achieve than quantitative XPS, as the latter shows only one photoelectron peak when the former exhibits many relaxation peaks laying over a 100 ev range. A good way to check our understanding of the Auger process is to simulate spectra. For that we need to get an estimation of (i) the ionization probability and its variation with depth, (ii) the contribution of each ionization and relaxation processes, and (iii) the type of interaction between electron and solid. As the phenomena are basically the same for the transport of Auger electrons as for primary electrons, we used the same physical parameters and simulation models (layer by layer and Monte Carlo) as we previously used for the determination of the background in copper. A comparison between calculated and experimental results is presented.
Quantitative AES: The establishment of a standard reference spectrum for the accurate determination of spectrometer transmission functions
Authors: Smith G. C. , Seah M. P. 
Published: May 2005

AbstractThe precise shape of the whole electron spectrum in AES is defined by (i) the physics of the process, and (ii) the intensity/energy transmission function of the measurement system. In many systems item (ii) is uncharacterized and surveys show variable effects of over an order of magnitude. This gives rise to equivalent errors in quantitative AES where published data banks are used and the spectrometers are uncalibrated.In this study we consider both the process and the measurement system, and show how the parameters of each may be measured and how each affects the final measured spectrum in the direct mode. The factors considered include the orientation of both the incident and emitted electrons, and the energy dependence of the transmissivities of the spectrometer and the detection system. Detailed measurements of high accuracy for a copper reference sample show the extent to which the reference procedures may be followed and equivalent data be recorded from different instruments.
An engery‐resolved electron stimulated desorption (ESD) study of oxygen‐exposed Ag (110)
Authors: Corallo Gregory R. , Hoflund Gar B. , Outlaw Ronald A. 
Published: May 2005

AbstractEnergy‐resolved ESD data obtained from Ag(110) after exposure to oxygen at room temperature are presented. The oxygen is found to desorb predominantly as a hydroxyl species. The surface hydrogen apparently originates from the bulk silver and is only removed slowly over many sample anneals. OH+ desorbs with an energy of 4.7 eV, and H+ desorbs with an energy of 3.0 eV. The results suggest that oxygen adsorbs at two or more different bonding sites on this surface. OH+ desorbs by ESD from the most prevalent of these sites, and O+ desorbs from another site which seems to fill first upon oxygen exposure. The primary beam energy is an important ESD variable since exciting the Ag 3d core levels results in a substantial reduction in the OH+ desorption yield.
Surface reactions during rapid solidification and handling of Al5Mn2.5Cr powders
Authors: Olefjord I. , Nylund A. 
Published: May 2005

AbstractRapidly solidified Al powders were analysed in the as‐received condition, and after exposure in humid atmospheres, using ESCA and Auger spectroscopy. The composition of the powder is Al5Mn2.5Cr. It was produced by the ultra sonic gas atomization (USGA) technique. The cooling rate was in the range 105–106 K s−1.The surface of the as‐atomized powder is partly covered by aluminium oxide particles formed at high temperatures during atomization and by a thin uniform oxide film formed between the oxide particles. The thin film is formed at low temperatures during atomization and during handling of the powder. The average thickness of the oxide is 50 Å.The powders were exposed in humid atmosphere at 22°C for 1 day and for 1 week, at relative humidities of 60% and 80%. During the exposure, aluminium hydroxide is formed on the surface of the oxide. The thickness of the hydroxide layer increases with exposure time and the humidity. After exposure for 1 week in relative humidities of 60% and 80% the thicknesses of the hydroxide layers were 10 and 12 Å, respectively.
Surface characterization of AISI 304L stainless steel subjected to various prebonding treatments. Correlation with adhesion measurements
Authors: Gaillard F. , Romand M. 
Published: May 2005

AbstractIn order to promote strong and durable steel/epoxy adhesive joints, various stainless steel surface treatments are investigated. The adherend surface characterization is achieved by both spectroscopic (low energy electron‐induced x‐ray spectrometry (LEEIXS), AES, XPS) and microscopic (SEM) techniques. The strength of the steel/epoxy bonds is evaluated, after bonded sample ageing under hydrothermal conditions (70°C, 95% r.h.), by means of a mechanical three‐point flexure test, sensitive to the interfacial properties of the bonded systems.The stainless steel surface treatments used in this study include conventional ones, such as solvent degreasing, acid etching, and phosphating and more original ones such as anodizing in sulphuric‐chromic or nitric acid electrolytes. These two last treatments lead to the formation of a ‘thick’ (in the range 10 to 90 nm) surface layer, highly chromium (as Cr(III))‐enriched, as determined by LEEIXS and XPS.The anodized stainless steel/epoxy systems exhibit performances which largely outclass those allowed by conventional steel prebonding treatments. These performances are very dependent upon the electrochemical conditions (current density, treatment duration, electrolyte temperature and composition) chosen for the anodizing process.
The application of surface analysis to studies of the environmental degradation of polymer‐to‐metal adhesion
Authors: Watts J. F. 
Published: May 2005

AbstractThe use of surface analysis in adhesion studies is reviewed and the various levels of information attainable is illustrated with a series of examples taken from studies of organic coatings on steel substrates. It is concluded that for a complete understanding of environmental degradation processes the intact interfacial bond must first be will understood, and failure in an inert atmosphere carefully documented.
Analysis of ion implanted ceramics. Studies of iron implanted MgO and Al2O3
Authors: Marest G. 
Published: May 2005

AbstractThe effects due to ion implantation in ceramics depend on different factors: nature of the material, beam parameters and also substrate temperature. At high fluences some metastable phases can be formed. To determine the surface modifications induced by ion implantation it is absolutely necessary to use various techniques very sensitive to rather low concentrations of impurities or able to probe very thin layers. An illustration of this necessity is given with studies of as‐implanted and annealed iron implanted sapphire and magnesium oxide surfaces. Rutherford backscattering spectroscopy (RBS‐c) was used to profile implanted iron and to follow lattice disorders as a function of annealing temperatures. Optical absorption spectroscopy and transmission electron microscopy have allowed the characterization of point defects and the determination of crystallographic structure of precipitates, respectively. The Mössbauer spectroscopy has allowed the determination of the charge states of implanted iron.
Topographic compensation in Auger electron spectroscopy
Authors: Sekine Tetsu , Sato Tomoshige , Nagasawa Yuji , Sakai Yuji 
Published: May 2005

AbstractThe scanning Auger microprobe (SAM) produces Auger images which provide information on the elemental distribution of specimen surfaces. However specimen topography affects the data obtained. To eliminate the topographical effect, the peak‐to‐background ratio, (P − B)/B ( = R), is often used instead of the net peak intensity, P − B. It was found that this method would provide reasonable quantitative results when the tilting angle of the facet plane against the primary electron beam incidence is less than approximately 50°. Over 50°, R would generally give higher values. At 80° R would be 1.2–3.7 times larger than that at 0°. In this paper we propose a new method to compensate for this deviation. Through specimen tilting experiments using a flat surface, we found a deformation of total background shape at high tilting angles. It is interpreted by γ, a background intensity ratio at two energies (ex. 2000 eV and 3000 eV). It was found that γ obeys a simple equation of tilt angle θ,

. Then, θ can be derived from the values of the background intensity ratios. The following relationship was also found between R0 and R

where R0 and Rθ are peak‐to‐background ratios at 0 and θ degrees, respectively, and E is the Auger transition energy. Since θ can be derived, we can always connect the peak‐to‐background ratio at θ to that in the horizontal state. Thus, elimination of topographic effect would be possible.We believe that this scheme would contribute to quantitative Auger imaging.
A technique for performing angle‐resolved electron energy loss spectroscopy: A study of polycrystalline tin
Authors: Hoflund Gar B. , Corallo Gregory R. 
Published: May 2005

AbstractA method is presented for performing angle‐resolved electron energy loss spectroscopy (ARELS) using a doublepass cylindrical mirror analyzer (CMA) which contains an angle‐resolving movable aperture. Both the electron gun contained in the CMA and an off‐axis electron gun are used in these studies. The technique is illustrated by ARELS spectra taken from a cleaned polycrystalline tin surface because observing the behavior of the surface and bulk plasmon features provides a direct and simple way of assessing surface sensitivity. The spectra demonstrate that the incidence angle of the primary beam, the collection angle with respect to the sample normal and the primary beam energy all have a very large effect on surface senstivity.
The status of reference data, reference materials and reference procedures in surface analysis
Authors: Grant J. T. , Williams P. , Fine J. , Powell C. J. 
Published: May 2005

AbstractA brief synopsis is given of recent developments and current needs for reference data, reference materials and reference procedures in surface analysis. This assessment is based largely on three presentations and related discussion at the Second Topical Conference on Quantitative Surface Analysis held at Monterey, California on 30–31 October, 1987. While a reasonable start has been made in recent years in providing needed data, materials, and procedures, many important needs remain.
Problems of quantitative Auger analysis of TiNx thin films: Peak overlapping and line shape changes
Authors: Pamler W. 
Published: May 2005

AbstractQuantitative Auger analysis of TiNx is not trivial because the only N transition coincides with a Ti peak and the shape of all Ti lines changes by compound formation. It will be shown in this paper that the effect of the line shape changes on quantification can be reduced by a degraded energy resolution, for example by additional smoothing of the raw spectra. Then, the overlap problem can be addressed by subtraction of an additional sensitivity factor which is determined by a pure Ti spectrum. Auger spectra will be quantified by means of reference samples. This calibration yields a good correlation of Auger intensities with bulk compositions. Moreover, the applicability of usual high resolution spectra for quantification will be discussed.