bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quantitative Auger electron spectroscopy of silicides by extended matrix correction using dN(E)/dE spectra
Authors: Wirth Th. 
Published: May 2005

AbstractAn extended matrix correction procedure is proposed which considers effects created by different atomic densities, electron backscattering, electron attenuation and peak shapes. Asymmetry factors are introduced that reflect line shape changes of signals in compounds or alloys very well. From asymmetry factors a peak shape correction factor is determined. To overcome the uncertainties in correction for changing electron attenuation, a new method for calculation of λ is presented. The results are compared with experimental values and tested in matrix correction. The concentration ratios obtained are compared with results using inelastic mean free path lengths or attenuation depths determined by the methods of Penn. Tanuma et al., Tokutaka et al. and Seah and Dench in matrix correction. For the determination of concentration ratios from samples of unknown composition, an iteration procedure is introduced. The extended matrix correction is applied on silicides such as VSi2, V5Si3, V3Si, CrSi2, Cr3Si, MoSi2, Pd2Si and PtSi, yielding results which are accurate to 7%. The weight of the individual correction factors in the extended matrix correction procedure is discussed, dependent on experimental conditions and sample constituents. Without correction for matrix effects, erroneous results up to 30% can occur.
An investigation of the surface chemistry of poly(ether etherketone). I. The effect of oxygen plasma treatment on surface structure
Authors: Pawson D. J. , Ameen A. P. , Short R. D. , Denison P. , Jones F. R. 
Published: May 2005

AbstractTime‐of‐flight secondary ion mass spectroscopy (ToF‐SIMS) and x‐ray photoelectron spectroscopy (XPS) have been employed to study the plasma surface oxidation of poly(ether etherketone) (PEEK). The positive and negative ion ToF‐SIM spectra obtained from a cleaned PEEK surface were easily interpreted using conventional mass spectrometry rules. Plasma oxidatio of PEEK was found to produce complex positive and negative ion spectra. In these spectra, ions diagnostic of the PEEK repeat unit were much reduced in intensity, and new ions diagnostic of plasma treatment were introduced. However, a thorough interpretation of these spectra was not attempted. The corresponding XP C 1s and O 1s core‐level spectra were run. In the C 1s core level, surface oxidation produces a number of new carbon–oxygen environments and an increase in the number of oxidized carbons. In both the C 1s and O 1s core levels, the increased full width at half‐maximum (FWHM) required to fit these spectra is suggestive of several environments being contained within each of the peaks fitted. The plasma‐treated polymer surface was rinsed with methanol. In the ToF‐SIM spectra, rinsing removes or reduces the intensities of the ions introduced by plasma treatment and enhances the intensities of some ions not previously noted; but rinsing does not restore the original PEEK spectra. In the C 1s core‐level spectrum, rinsing was found to reduce the number of oxidized carbons and, in particular, the concentration of the environments introduced by plasma treatment. Further, it proved possible to fit the C 1s core level with a FWHM comparable to that employed for the clean PEEK: this may be indicative of a reduction in the variety of carbon–oxygen environments.
Characterization of interfaces in ceramic composites by SIMS, AES and EPMA
Authors: Mischler S. , Bishop H. E. , Davies J. J. R. 
Published: May 2005

AbstractFracture surfaces and polished cross‐sections of aligned SiC fibre–cordierite matrix composites have been studies using SIMS, AES and electron probe x‐ray microanalysis (EPMA). It has been shown that, during fabrication, interface reactions resulting in penetration of the fibres by matrix cations take place. Titanium diffusion out from the fibres together with segregation of matrix elements to the interface is also observed. A correlation is found between interface composition and mechanical properties of the composites. The relative merits of SIMS, AES and EPMA in the determination of the nature of the fibre‐matrix interface are discussed. SIMS using a microfocused Ga ion beam is shown to be a powerful new tool in the investigation of interfaces.
Optical ellipsometry and electron spectroscopy studies of copper oxidation related to copper on printed circuit boards
Authors: Manara A. , Sirtori V. , Mammarella L. 
Published: May 2005

AbstractThe aim of the present work was to investigate the oxidation of pure copper samples and of those cut out from circuit boards by using optical ellipsometry XPS and AES, in order to establish whether ellipsometry alone could be used as a simple, economical means for routine analysis at the wiring line of circuit boards.Samples of pure copper, with a polished surface or after treatment in an ENTEK solution, were oxidized for different lengths of time at 180°C, the temperature at which circuit boards are heated before the soldering and wiring process. The oxide growth rate is constant for thicknesses of the oxide layer up to ∼ 100 Å. The thicknesses measured by XPS/AES depth profiles agree well with those measured by ellipsometry provided that two oxide films, Cu2O and CuO, are present for oxidation, while CuO begins to form at later stages.An empirical correlation between the experimental ellipsometric and Auger spectroscopy data on 50 samples cut out from circuit boards, before and after the wiring process, permitted the oxide thickness and the quality of the copper surface of the circuit boards to be estblished by ellipsometry alone. An ellipsometer was installed on the assembly line of the circuit boards and is used for routine analysis of the copper surface of the boards.
Electronic properties of disordered anodic TiO2 (001) surfaces: Application of the equation‐of‐motion method
Authors: Tit Nacir , Halley J. W. , Michalewicz M. T. 
Published: May 2005

AbstractWe report calculations of the electronic properties for rutile TiO2 (001) surfaces using the equation‐of‐motion (EOM) method. We use a full tight‐binding Hamiltonian developed by Vos to describe the electronic structure. In contrast to the Green's‐function (GF) method which is traditionally used for such a problem, the EOM method gives excellent results with large systems and any number of defects, and puts no restriction on the range of the impurity potential. There is experimental evidence that the observed gap state at 0.7 eV below the conduction‐band edge is due to an oxygen vacancy. For this reason we study the electronic properties of disordered surfaces as a function of oxygen vacancy concentrations (up to 10%). Our results are applied to the interpretation of recent scanning tunneling Microscopy (STM) experiments on anodic rutile TiO2 (001) films (whose thickness is ∼ 150 Å), and the density of surface defects is estimated. Special care was paid to the study of the nature of gap states. Our results show that these states are localized and play the role of trapping centers which impede the conduction in the films and that no impurity band exists for the studied surfaces. We use both conductivity and local density of states (LDOS) calculations to draw this conclusion. In agreement with experiments, no contribution from gap states in the transport was confirmed in our work. We also report the LDOS calculations on a few sites around the defect at the surface. This in turn gives information about both the spatial decay of the bound‐state wave function (localization) and the existence of the impurity band.
Rapid characterization of an unknown optical coating on soda‐lime silica glass using dynamic SIMS
Authors: Carlson Brad A. , Phillips Bradway F. 
Published: May 2005

AbstractAn unknown optical coating deposited on unpolished soda‐lime silica float glass was analyzed using dynamic secondary ion mass spectrometry (SIMS). This investigation was performed to determine the composition and layering structure of the optical coating. Results obtained in this analysis showed the number and thickness of layers making up the coating, as well as the elemental composition of each layer. More importantly, the entire investigation took less than 2 h to complete. This demonstrates the ability of SIMS to perform a rapid characterization of a complex insulating multilyer thin‐film system deposited on a rough surface.
Application of sample rotation to secondary ion mass spectrometry depth profiling of aluminum metallization
Authors: Stevie F. A. , Moore J. L. 
Published: May 2005

AbstractAluminum films sputter‐deposited on silicon have been analyzed using secondary ion mass spectrometry with sample rotation during O2+ ion bombardment. Sample rotation prevented bombardment‐induced topography formation and associated loss of depth resolution. Analysis of silicon and boron ion implants into aluminum showed that, compared with the unrotated sample results, rotation did not significantly affect the implant shape, but dramatically improved the characterization of the interface at the bottom of the aluminum layer. For the analysis conditions used, silicon sputtered at approximately twice the rate for aluminum. Sample rotation allowed the correct sputtering rate to be applied to the layer and substrate and thereby provide an accurate depth scale that was not possible for the poorly defined interface without rotation. Aluminum films deposited on silicon at ambient temperature were shown to have an absence of silicon near the aluminum/silicon interface, whereas deposition at 300° C results in a silicon gradient as the interface is approached. Boron was detected below the 1 part‐per‐million atomic level using sample rotation, and boron at the aluminum/silicon interface was clearly defined.
Quantitative surface analysis of layered materials
Authors: Holloway Paul H. , Bussing Tom D. 
Published: May 2005

AbstractThe effects of concentration variation with depth, C(X), on the quantitative reduction of electron spectroscopic data is discussed. It is shown that when the concentration varies with depth, quantitation of the data is affected by the escape depth of the electron transitions chosen for quantitation. Therefore, accurate quantitation is impossible without knowledge of C(X). A Laplace transform method to determine C(X) from angle‐resolved electron spectroscopic data is reviewed, along with potential problems caused by variation with angle of the escape depth of electrons in the solid, channeling, forward scattering, matrix corrections and surface roughness.
Adhesion study of polyimide to SI surfaces
Authors: Jeong Hyo‐Soo , White R. C. , Chu Y. Z. , During C. J. 
Published: May 2005

AbstractThe blister test is applied to the type of thin‐film structures used in microelectronic packaging. The main advantage of this test is that most of the energy expended is responsible for interfacial fracture, allowing the determination of a fracture energy that closely represents the true interfacial adhesion strength between a thin film and a rigid substrate. It has been proved quantitatively that surface modification contributes to enhanced adhesion. It is found that the critical pressure at which debonding occurs does not correlate with the fracture energy measured in the blister test. Reproducibility of the fracture energy is exceptionally good and allows determination of the optimal thermal condition for promoting adhesion of polyimide on silicon surfaces.
Chromium oxidation states and XPS analysis of the chromia/zirconia system
Authors: Gazzoli D. , Occhiuzzi M. , Cimino A. , Minelli G. , Valigi M. 
Published: May 2005

AbstractX‐ray photoelectron spectroscopy (XPS) has been applied to the study of the oxidation state variations of Cr ions in the chromia/zirconia system (CrOx/ZrO2) submitted to redox cycles: O2 at 773 K (standard oxidation), CO at 673 K (standard reduction) and H2O after standard reduction at 743 K. The XPS results are compared with those coming from the average oxidation number determination (n) by redox cycling and with electron spin resonance (ESR) analysis, particularly with regard to the Cr(V) identification. The results show that equilibrium adsorption of chromic acid on zirconia gives Cr(VI) species (binding energy ∼ 580 eV). The XP Cr(VI) feature shows a continuous evolution towards reduced chromium states as the samples age. After oxygen treatment, in addition to Cr(VI), the presence of a component at 1 eV lower binding energy is required to reproduce the spectral feature. This component was assigned to Cr(V) on the basis of ESR and average oxidation state results. Thermal treatment in CO (standard reduction) results in a broad (4.5−5.5 eV) and unresolved Cr 2p feature. The presence of Cr(II) at 576.0 ± 0.2 eV was established by curve fitting procedures. Cr(II) is destroyed by H2O treatment at 743 K, with ensuing formation of Cr(III) species.
Interface analysis in polysilicon thin films and poly‐Si/SiO2 systems
Authors: Nakhodkin N. G. , Rodionova T. V. 
Published: May 2005

AbstractCross‐sectional transmission electron microscopy (TEM) has been used to study interface morphology in undoped and P‐doped polysilicon films and poly‐Si/SiO2 systems deposited by low‐pressure chemical vapour deposition. Two types of polysilicon interface are found: a ‘toothed’ interface in films with fibrous structure and a flat uniform interface in P‐doped polysilicon films. The conditions for the formation of these interface types have been analysed. The morphology of the poly‐Si/SiO2 interface is studied in relation to its dependence on both the original structure type of the polysilicon films and the oxidation temperature.
Monte Carlo analysis of XPS and REELS spectra obtained at different take‐off angles
Authors: Yoshikawa Hideki , Tsukamoto Tadayuki , Shimizu Ryuichi , Crist Vincent 
Published: May 2005

AbstractIn the previous work such a ‘best‐fit’ loss function for Au was derived from Monte Carlo simulation analysis, which describes the experimental Au 4f XPS background spectrum very well with the approximation that the contribution of the intrinsic energy loss is negligible. This best‐fit loss function was supposed to include considerable contributions of the surface excitations as well as the bulk excitation. In the present work we performed not only XPS but also REELS measurements at different take‐off angles, which allowed us to examine the applicability of the best‐fit loss function to more general cases.Comparison of experimental results with simulated results has revealed that the contribution of the surface excitation to the loss spectrum is indeed significant, leading to the conclusion that the loss function in XPS and reflection electron energy‐loss spectroscopy (REELS) is directly dependent on the take‐off angle. Contributions from the surface excitation to the background intensity are also discussed.
High dynamic range SIMS depth profiling on in situ ion‐beam‐generated mesas using the ion microscope
Authors: Gillen Greg 
Published: May 2005

AbstractThe dynamic range of SIMS depth profiles of high‐dose ion implants can often be improved by removing the influence of the highly doped crater walls from the depth profile. This is accomplished either by collapsing the primary beam raster or by using specialized sample preparation techniques such as the mini‐chip or dot‐etching methods developed by von Criegern et al. The main limitations with the sample preparation techniques are that they are labor and time‐intensive and are not applicable to all substrate types. By a simple modification of the raster circuits of an ion microscope, it is possible to generate, by sputtering, a mesa structure that is subsequently profiled under normal conditions. This approach offers a rapid, flexible method of mesa preparation that is amenable to all sample materials. The principal disadvantage with the use of the ion microscope for this analysis is that a significant memory effect can result from the dopant species that are sputtered during the preparation of the mesa structure.
Chemical analysis of passivated and oxidized layers on FeCr and FeTi alloys by soft x‐ray absorption spectroscopy
Authors: Soriano L. , Abbate M. , de Groot F. M. F. , Alders D. , Fuggle J. C. , Hofmann S. , Petersen H. , Braun W. 
Published: May 2005

AbstractThe chemical differences between passivated and oxidized layers on 17.5 at.% FeCr and 5 at.% FeTi alloys are analysed by means of soft x‐ray absorption spectroscopy (XAS). The relative absorption strengths were used to obtain a quantitative estimation of the composition of the layers. In FeCr, the passivated layer shows a relative Cr enrichment of 34 at.% with respect to the oxidized surface. In addition, Cr2O3 has been identified as the main oxide formed in the passivated layer of FeCr. By contrast, in FeTi, the results are consistent with the formation of a ternary oxide. The potential of XAS in the study of oxidation and passivation is discussed.
Investigation of the surface activity of corrosion inhibitors by XPS and time‐of‐flight SIMS
Authors: Swift Andrew , Paul Alan J. , Vickerman John C. 
Published: May 2005

AbstractX‐ray photoelectron spectroscopy (XPS), time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) and infrared spectroscopy (IR) have been used to study the interaction of two corrosion inhibitor blends of unknown composition with an iron surface. The analysis has precisely identified quaternary ammonium and tertiary amine compounds that are key ingredients of each inhibitor blend and has shown that inhibitor A forms a thicker and more effective layer than inhibitor C. Further analysis by angle‐dependent XPS has revealed that, for both inhibitors, the quaternary ammonium and tertiary amine molecules adopt a layered arrangement on the iron surface. No evidence of direct chemical bonding between inhibitor and substrate is identified and no evidence of molecular association of inhibitor molecules is found. A mechanism involving the organized interaction of discrete quaternary ammonium molecules to the iron surface is proposed.
Calculations of electron inelastic mean free paths (IMFPS). IV. Evaluation of calculated IMFPs and of the predictive IMFP formula TPP‐2 for electron energies between 50 and 2000 eV
Authors: Tanuma S. , Powell C. J. , Penn D. R. 
Published: May 2005

AbstractWe have made additional evaluations of the electron inelastic mean free paths (IMFPs) and of the predictive IMFP formula TPP‐2 presented in papers II and III of this series. Comparisons have been made with other formulae for the IMFPs and electron attenuation lengths (ALs). We find substantial differences between our IMFP results for 27 elements and 15 inorganic compounds and the AL formulae of Seah and Dench; these differences include different dependences on electron energy and on material parameters. We present IMFP calculations for Al2O3 and GaAs from TPP‐2 in which each parameter of the formula is varied in some physically reasonable range about the true value for each compound; these results show the sensitivity of the computed IMFPs to the choices of parameter values. Finally, we give a summary of sources of uncertainty in the IMFP algorithm, in the experimental optical data from which IMFPs are calculated, and of the TPP‐2 formula. We conclude that TPP‐2 is robust and useful for predicting IMFPs for electron energies and material parameter values in ranges for which the formula was developed and tested.
Non‐destructive characterization of polymide/copper and polyimide/gold interphases using surface‐enhanced Raman scattering and reflection–absorption infrared spectroscopy
Authors: Young J. T. , Boerio F. J. 
Published: May 2005

AbstractThe molecular structure of interfaces formed by curing the polyamic acid of pyromellitic dianhydride (PMDA) and oxydianiline (ODA) against copper and gold substrates was determined using surface‐enhanced Raman scattering (SERS) and reflection‐absorption infrared spectroscopy (RAIR). It was found that acid groups of the polyamic acid reacted with metal ions on the substrates to form carboxylate salts when the polyamic acid was spin‐coated onto metal substrates. Formation of carboxylates on the copper surface extended several hundred angstroms into the polyamic acid films, while only trace levels of carboxylate were formed on the gold surface. Formation of carboxylate salts suppressed the curing of polyamic acid on copper substrates. However, the degree of curing of the polyamic acid was high on gold surfaces. These results were compared to our previous work concerned with the molecular structure of interfaces between PMDA/ODA polyimides and silver substrates. The extent of carboxylate formation on silver was intermediate between those on copper and gold. Results obtained from SERS and RAIR also indicated that cured polyimide films above the partially cured layers were oriented edge‐on, with the PMDA moieties perpendicular to the metal surface and the ODA moieties mostly parallel to the surface.
Ceramic coating chemically vapour deposited on high speed steel substrates: Scratch adhesion test phenomena
Authors: Naeem Z. , Smith A. B. , Lamsehchi M. , Critchlow G. W. 
Published: May 2005

AbstractThe scratch test is widely used to assess the adhesion of ceramic coatings deposited on cermet and alloy substrates by both physical vapour deposition and chemical vapour deposition (CVD). It has been observed during such tests that, depending on the coating type, complete coating removal from the scratch channels can be preceded by flaking of the coating at the edges of the channels. An attempt has been made to ascertain, for CVD coated powder metallurgy (PM) high speed steel (HSS) cutting tool inserts, whether a relationship exists between the presence/absence and type of pre‐critical load coating flaking observed during scratch testing and interfacial compositional variations determined by Auger electron spectroscopy (AES). Scratch test and AES results are presented for the following CVD coated PM HSS inserts: titanium nitride (TiN) coated, where no flaking has been observed; titanium carbide (TiC) coated, where mixed adhesive/cohesive flaking of the TiC coating has been observed and multilayer aluminium oxide (Al2O3) coated, where adhesive flaking of the Al2O3coating has been observed. In the case of the TiN and TiC coated inserts it is not considered that differences in coating/substrate interdiffusion zone thickness alone are responsible for the observed divergence in scratch test behaviour. Differences in coating microhardness are also suggested to be a significant factor. The behaviour of the multilayer Al2O3 coated insert during scratch testing is thought more likely to be singularly associated with interfacial chemistry.
Surface modification of polymethylmethacrylate by UV light as studied by TOF‐SIMS
Authors: van der Wel H. , Lub J. 
Published: May 2005

AbstractIn the present paper the chemical modification upon exposure with UV light of 185 nm and 254 nm in an Ar atmosphere of the surface of polymethylmethacrylate (PMMA) is studied with time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS). The results show that UV photodegradation of PMMA does not induce large changes in the TOF‐SIMS spectra. However, changes in the relative peak intensities for the photolysed samples and comparison with results from PMMA fragmentation upon ion bombardment show that the photodegradation has proceeded to a considerable extent. In addition, small peaks are observed due to ions that originate from oxidized PMMA groups.