bluuebunny/crossref_metadata_2025_split huggingface dataset:
X‐ray photoelectron spectroscopy and surface charge build‐up used to study residue on aluminum contacts on integrated circuits
Authors: Thomas J. H. , Bryson C. E. , Pampalone T. R. 
Published: December 2004

AbstractX‐ray photoemission induced surface charge build‐up with a charge control screen and small spot analysis was used to study processing residue layers deposited on aluminum–silicon metallization as found in high aspect ratio via regions on silicon integrated circuits. Chemically vapor deposited silicon dioxide on Al: 1% Si metallization is commonly found in double level metallization of intergrated circuits. An interdigitated fine‐line test pattern with lines ranging from 500 nm to 2000 nm and variable spacing was used to simulate a typical integrated circuit structure. X‐ray photoemission studies of processed test circuits have led to the following conclusions. Line patterns CHF3 plasma etched into 800 nm SiO2 to expose Al were found to be contaminated with a dominant carbide and a minor oxyfluoride compound. Both Al carbides and Al oxyfluorides are non‐volatile compounds and hence are not readily removed during plasma etching or ashing. This surface layer is deposited by a combination of fluorine in the plasma interacting with the aluminum surface, side wall deposition of carbon from the photoresist, and ion induced mixing of the surface region. Deposits found on similarly processed planar structures were contaminated with Al oxyfluoride and no detectable amount of carbide. Back‐scattered Al(OF)x was observed on the SiO2 surface due to the plasma ashing photoresist removal step.
A Raman spectrophotometric investigation of the phases formed during the cobalt silicidation by rapid thermal anneal
Authors: Shergill Gurmeet S. , Wei Chih‐Shih , Cox J. Neal , Fraser Dave B. , Murray Jeff J. 
Published: December 2004

AbstractRaman spectrophotometry was used to determine the various phases of cobalt silicide formed during rapid thermal annealing of cobalt films deposited onto silicon (100) substrates. The samples were prepared by depositing a 600 ÅR cobalt film and then letting the reaction occur in a nitrogen ambient. Annealing was done for 20 s at temperatures ranging from 200 to 1000°C. The unreacted cobalt film was removed from the surface for the Raman spectrophotometric study. The initial phase, characterized as Co2Si, formed at 250°C. Two subsequent phases, CoSi and CoSi2, were identified as forming at 300 and 500°C, respectively. The corresponding three Raman peaks appeared at 204, 306 and 515.3 Δcm−1, respectively. These peaks appeared and disappeared in accordance with the phase change in the film. The co‐existence of the two initial phases, Co2Si and CoSi, at temperatures near 300°C was also evidenced by Raman spectrophtometry. The Raman data correlated well with Auger electron spectroscopic depth profiles.
SIMS analysis of GaP–GaAsP layered structures
Authors: Söudervall U. , Leys M. R. , Lodding A. , Samuelson L. 
Published: December 2004

AbstractThe paper describes the characterization by SIMS of thin layers of GaAsxP1 − x between layers of GaP. The investigation aims at quantification of the arsenic concentration, x, in layers with thickness ranging from 20 to 100 nm.The study reveals a nearly constant sensitivity factor in the SIMS quantification of the arsenic content of the GaAsxP1 − x layers. The sensitivity factor was found to be 4.3 × 10−3 over the range x = 0.10–0.75, with no distinct concentration dependence.Depth resolution and decay length λ(0) were measured by analysing the interfaces of the GaAsxP1 − x structures at different primary ion energies (1.5–13 keV). The best depth resolution, 3.2 nm, is obtained at 1.5 keV and the worst, 13 nm, at 13 keV. Decay length evaluations are consistent with a collisional mixing theory for the sputter‐induced broadening of an interface.
Factor analysis of d(NE)/dE Auger electron spectra of AuCu alloys: Surface composition during Ar+ ion bombardment and oxidation
Authors: Jansson C. , Morgen P. 
Published: December 2004

AbstractFactor analysis is applied to d(NE)/dE Auger electron spectra of a series of AuCu alloys (25% Au, 50% Au and 75% Au), including in the analysis the spectra of clean Au and Cu surfaces. Surface quantitation is obtained from the low‐energy Au NOO and Cu LMM spectra of the alloys. The overlap of these spectra is resolved with factor analysis. An accuracy of the derived, relative surface concentrations of 1:100 is possible with this method, with a similar sensitivity to changes in surface composition. During Ar+ ion bombardment the surfaces of 25% and 50% Au alloys show no difference from the bulk concentrations, within ±1:100, from 1 to 3 keV Ar+ ion energy. For the 75% Au alloy, a slight Au enrichment is produced, when the energy increases from 1 to 3 keV. However, at 500 eV Ar+ ion energy, the surfaces become strongly enriched in Au, probably due to threshold effects for Au. Thus, no evidence for such strongly varying processes are found in molecular dynamics simulations of the mass effect in the sputtering process from a 50%:50% alloy. Factor analysis is also used to detect the presence of chemically affected spectral features during oxygen exposure at room temperature of the alloys and of pure Cu. Oxidation of the copper component is observed, producing at saturation a cuprous oxide with a total copper enrichment of the surface.
Secondary effects in laser ionization surface analysis
Authors: Rohr K. , Thoemmes R. 
Published: December 2004

AbstractContaminated tantalum surfaces have been analysed by a modified laser ionization mass analysis (LIMA) technique in order to investigate the reliability of this method in a situation where the ion yield is optimum. The laser was an Nd‐YAG Q‐switch system (λ = 1.06 μm) of τ = 20 ns pulse length delivering an energy of 0.3 J in the TEM00 mode. Ions desorbed from the surface and the substrate have been analysed according to their mass and charge and their kinetic energy distribution. The results strongly suggest that the effective region of the surface desorption can be one order of magnitude larger than the geometrical focal region of the laser beam where the substrate particles are desorbed. The effect is explained by secondary Bremsstrahlung interaction. Generally, this imposes severe restrictions on the reliability of quantitative spatially resolved surface analysis techniques where laser‐induced high‐temperature plasmas are present.
Analysis of superconducting thin films by ion beam methods. Comparison of nuclear techniques and SIMS
Authors: Stoquert J. P. , Fogarassy E. , Stuck R. , Guillaume G. , Siffert P. , Perrière J. 
Published: December 2004

AbstractThin layers of YBaCuO and BiSrCaCuO superconducting oxides have been deposited on different substrates by the laser evaporation technique using a pulsed ArF excimer laser. The films were analysed by different ion beam techniques: nuclear reaction (NR), particle‐induced x‐ray emission (PIXE), Rutherford back‐scattering (RBS), elastic recoil detection (ERD) with high‐energy incident ions, and secondary ion mass spectroscopy (SIMS). Conventional PIXE and RBS with proton and helium beams were used to determine the mean stoichiometry and the near‐surface composition for the heavy elements of the target, and the 16O(d, α)14N nuclear reaction was employed at Ed = 900 keV (θd = 150°) to profile the oxygen content in the layers. In order to obtain detailed information on the variations of the relative concentration in depth, SIMS was also performed on thin layers and on bulk superconducting target prepared by standard ceramic techniques. Absolute profiles of matrix elements, from O to Bi, were also determined by the ERD technique using high‐energy (up to 240 MeV) heavy incident ions (127I) and a ΔE–E gas telescope in order to discriminate between the recoiling atoms.Finally, the resolution and sensitivity of the different methods are compared.
Secondary ion shadow‐cone enhanced desorption
Authors: Chang Che‐Chen 
Published: December 2004

AbstractThe incident angle dependence of the secondary particle emission process under keV ion bombardment has been investigated. The results from the full molecular dynamics calculations indicate that the flux anisotropy of the incident beam, resulting from the non‐uniform impact parameters for the surface atom of a single crystal, affects the particle desorption in a systematic fashion. The enhanced desorption at certain angles of incidence corresponds to the intensive focusing of the incident beam to the near‐surface atom and the extended dissipation of momentum by large‐angle scattering. This observatvon has led us to develop a new theoretical model in which the enhanced desorption is described by the distance of closest encounter along the trajectory of the incident particle to the surface atom. The computer time for the simulation of the incident‐angle‐dependent emission process is significantly reduced. The results from the calculation based on this model are in good agreement both with the results from the full dynamics calculation and with the experimental results. The new model also allows a complementary evaluation of the microscopic dynamics involved in the shadow‐cone enhanced desorption.
A fracture technique for Auger analysis of a zinc/steel interface
Authors: Eberle W. J. 
Published: December 2004

AbstractA low‐temperature fracture technique was used to expose an extremely thin aluminium interface located between a very thick hot‐dip galvanized coating and a steel substrate. The representative sample was saw‐cut through the steel substrate just short of the hot‐dip galvanized interface, immersed in liquid nitrogen and fractured. The exposed aluminum‐rich boundary layer was analyzed by scanning Auger microscopy (SAM) to determine the effects of the galvanizing process on the boundary layer development.
Identifying type 304 stainless steel flange defects using scanning Auger microscopy (SAM)
Authors: Eberle W. J. , Clough S. P. 
Published: December 2004

AbstractAn unusual number of large stringer defects were found in cross‐forged type 304 austenitic stainless steel ultrahigh vacuum (UHV) flanges. These defects are cosmetically displeasing, they can affect the material's machinability and they can also affect the vacuum integrity of a UHV system. In this study, scanning Auger microscopy was used to identify accurately the defects as ferritic inclusions. This information was used to justify a change in forging and heat‐treating procedures, resulting in the reduction of large ferrite segregants and creating a more homogeneous microstructure. Subsequently, the rejection rate was reduced more than 50‐fold.
Chemical shifts in the MNN Auger spectra of Cd, In, Sn, Sb and Te
Authors: Lynn L. C. , Opila R. L. 
Published: December 2004

AbstractThe MNN Auger spectra of a series of elements, Cd through Te, have been examined as a function of chemical state. The spectra of Cd, In, Sn and Sb do not change shape significantly whether the element is present as a metal, semiconductor or insulator, e.g. Cd, CdTe or CdO. The Kinetic energies of the Auger electrons do shift by large, easily measurable, amounts of 3–6 eV. These shifts are to lower kinetic energy with respect to the pure metal and are largest for the oxides and least for the semiconductors. These spectra are atom‐like and the two final‐state holes are localized on one atom. The shape of the MNN Auger spectrum of Te reflects changes in its chemical state and shows shifts in energy similar to those seen for Cd, In, Sn and Sb. The changes in energy are much larger than those seen in photoemission and are the result of changes in the extra‐atomic screening of the double‐charged final‐state ion.
AES: Energy calibration of electron spectrometers. II—results of a BCRinterlaboratory comparison co‐sponsored by the vamas SCS TWP
Authors: Seah M. P. , Smith G. C. 
Published: December 2004

AbstractAn interlaboratory assessment of the kinetic energy measurement of Auger electron peaks has been conducted using reference foils of copper, silver and gold. The results, involving data from spectrometers manufactured by seven companies, were received from 39 laboratories. The standard deviations of the data in both the direct and differentiated spectra were ∼60% of the values found in the ASTM‐sponsored round robin in 1982, indicating only marginal improvements in spectrometer calibration since that time. By comparing the copper M2,3VV and L3VV measurements from the sets of returned data with the reference values from Part I, the energy scale and energy zero errors were calibrated for each instrument. Using these values and the relativistic term for the particular spectrometer, corrections to the respondees' values for the Ag M4NN, Au N6,7VV and Au M5N6,7N6,7 peak energies could be determined. The scatters of these calibration‐corrected values were very low, amounting to ∼15% of the values in the ASTM round robin for all of the spectrometers tested, but reducing to only 6% for the high‐resolution spectrometers. For both the direct and differential modes the calibration‐corrected Au N6,7VV and Ag M4NN average peak positions diverged by less than the 0.07 eV standard deviations of their means from the reference values given in Part I. The copper reference values given in Part I thus appear to be suitable for calibrating AES instruments to an accuracy comparable to the measurement repeatabilities of the instruments concerned and seem to be quite sufficient for their overall energy calibration.
SSIMS, XPS and microstructural studies of ac‐phosphoric acid anodic films on aluminium
Authors: Johnson D. , Vickerman J. C. , West R. H. , Treverton J. A. , Ball J. 
Published: December 2004

Abstractac‐Phosphoric acid anodizing of aluminium results in the initial formation of a featureless barrier film on the metal surface, followed by nucleation and growth of a filament structure. The rate of filament growth and filament diameter are dependent upon the anodizing temperature. Static secondary ion mass spectrometry (SSIMS) and XPS indicate that organic contamination levels on all anodized surfaces are low regardless of anodizing temperature and that contaminant levels tend to decrease as anodizing proceeds. Apart from the very intense Al+ in the positive ion spectra and the O− and OH− peaks in the negative ion spectra, SSIMS spectra were characterized by the appearance of a series of peaks from AlxOyHz fragments. Appearance of AlO+ or AlOH+ clusters in the positive ion spectra depended on the anodizing conditions. Both XPS and SSIMS confirm the presence of phosphates on the anodized surfaces but differences in results from the two types of analyses imply that unknown factors affect the concentration present.Low contaminant levels, corrosion inhibition from surface phosphates and the filamented topography developed will all affect the adhesive properties of the surface.
Improved depth resolution in Auger depth profiles of TiN thin films by optimized sputtering parameters
Authors: Pamler W. , Wildenauer E. , Mitwalsky A. 
Published: December 2004

AbstractThe depth resolution in Auger in‐depth profiles of TiN thin films on smooth Si substrates is determined by the evolution of a sputter‐induced surface roughness. It is shown that this effect depends critically on the ion angle of incidence. Therefore, the depth resolution can be improved most efficiently by optimizing the bombardment angle. The ideal sputter angle for Ar+ ions is found to be ∼76° and for Xe+ ions >80° to the surface normal, although slightly less grazing angles of incidence are preferred for more practical sputter rates. For any angle, the depth resolution can be improved further by reducing the ion energy and using Xe+ instead of Ar+ ions for etching. Thus, for TiN thicknesses of 83 nm and 650 nm, the sputter‐induced interface broadening can be as low as 3.5 nm and 8 nm, respectively.
XPS determination of oxygen‐containing functional groups on carbon‐fibre surfaces and the cleaning of these surfaces
Authors: Desimoni E. , Casella G. I. , Morone A. , Salvi A. M. 
Published: December 2004

AbstractCareful curve fitting is needed when using XPS to investigate oxidized functional groups on carbon‐fibre surfaces. This is important because the core regions often contain a number of overlapping features some of which are of low intensity, and the C 1s region is influenced by an asymmetric graphitic feature. The fitting approach used requires that the same content of oxygenated species must be obtained from both the C 1s and O 1s regions. The approach is used to analyse untreated fibres before and after cleaning.
Quatitative AES: Reducing errors in measured analogue spectral intensities through control of the electron detector
Authors: Seah M. P. , Smith G. C. 
Published: December 2004

AbstractAES spectra, when measured in the constant ΔE/E mode, may be distorted by the varying efficiency of the electron detector, usually a channel electron multiplier (CEM). In the analogue mode, this is a problem that increases as the emitted electron energy falls below 200 eV. Instruments may be modified by adding transparent meshes and by biasing the front of the CEM by 200 eV. In this way, the spectral distortion may be reduced by a factor of 10 at 50 eV, so that the resultant spectral shape is within ±10% of the true shape over the energy range 25–2000 eV. This small distortion may be calibrated accurately so that true spectra may be derived from all modified instruments with greater reliability and confidence than in unmodified instruments.
Thermal stability of benzotriazole on copper during atmospheric corrosion
Authors: Christensen T. M. , Sorensen N. R. 
Published: December 2004

AbstractAtmospheric corrosion of copper can result in substantial problems for electrical interconnection in microelectronic applications. We have used x‐ray photoelectron spectroscopy (XPS) to examine the effects of benzotriazole (BTA), an organic corrosion inhibitor, on atmospheric oxidation and sulfidation of polycrystalline copper in the temperature range 30‐200 °C. XPS results demonstrated that BTA was lost depended on the ambient composition. BTA was least stable in sulfur‐containing environments, disappearing from the surface at temperatures above 150 °C. BTA was quite stable in pure nitrogen and in a vacuum up to temperatures near 200 °C. This suggests that the loss mechanism involved a chemical reaction rather than solely a thermal process. The BTA‐Cu(II) complex existing at room temperature was irreversibly converted into a BTA‐Cr(I) complex upon heating above 90 °C in a vacuum.
XPS peak shapes accounting for the inelastic scattering of photoelectrons
Authors: Végh János 
Published: December 2004

AbstractA simple and fast method to account for inelastic scattering of photoelectrons is presented. A new peak shape class is introduced, which consists of a conventional photopeak and a tail originating from the inelastic scattering of the electrons, created originally in the photopeak. The proposed peak shapes with inelastic tail can be described using up to three additional parameters. The method has both practical and computational advantages.
Characterization of MoSi2 coatings obtained by atmospheric pressure and low‐pressure plasma spraying
Authors: Zacchetti N. , Mizuno K. 
Published: December 2004

AbstractThe high‐temperature oxidation resistance property of MoSi2 coatings is strongly influenced by the chemical composition, density and structure of the deposit. The aim of this work is to determine the role of the deposition process in the microchemistry and microstructure of the coating. In order to achieve this task, we compare MoSi2 produced by LPPS (low‐pressure plasma spraying) and conventional APPS (atmospheric pressure plasma spraying) techniques with the aid of a complementary use of characterization methods such as SEM, EPMA (electron probe microanalysis), CMA (computer‐aided microanalysis), GDOS (glow discharge optical spectroscopy) and XPS. From the overall results it is evident that the application of plasma spraying under low pressure considerably improves MoSi2 layers. They are characterized by a higher density, with fewer pores and discontinuities, and have a more uniform chemical composition and a better coating‐substrate interface.
Oxygen‐induced surface segregation of hydrogen in polycrystalline titanium
Authors: Azoulay A. , Atzmony U. , Mintz M. H. , Shamir N. 
Published: December 2004

AbstractOxygen‐induced surface segregation of hydrogen has been investigated in polycrystalline titanium. It was found that sulphur impurities in titanium preferentially segregate to the surface on heating the sample. Consequently, the properties and reactivity of the sulphur‐containing surfaces were modified relative to sulphur‐free samples in a way which enabled the performance of quantitative kinetic segregation measurements utilizing direct recoil spectrometry (DRS). The time behaviour of hydrogen accumulation on the surface pointed to a segregation mechanism involving subsurface‐to‐surface hopping as the rate‐determining step.
Some practical applications of elastic peak electron spectroscopy
Authors: Jardin C. , Gergely G. , Gruzza B. 
Published: December 2004

AbstractPractical applications of elastic peak electron spectroscopy (EPES) are presented to demonstrate the advantages of this technique in the study of materials subjected to electron beam degradation and surfaces involving hydrogen species. Beam damage on phthalocyanine layers is detected at low beam power (Ep = 500 eV, Jp = 10−3 A cm−2, grazing incidence angle 20°) with a cross‐section of about 8 × 10−18 cm2, as deduced from EPES experiments. The change in the emission yield of elastically reflected electrons during electron irradiation of this ’fragile‘ molecular material is related to an increase in the mean atomic number due to breaking of CH bonds and to desorption of hydrogen. Using very low current density to prevent primary beam effects, the distinction between different metal phthalocyanine layers (PcZn and Pc2Lu) and the study of diffusion induced by heat treatments are possible by EPES, in contrast to AES and EELS (electron energy loss spectroscopy) techniques. Application of EPES to the analysis of titanium alloy TA6V submitted to a hydrolysis treatment in hot water is also reported. The enhancement in elastic scattering with decreasing primary energy suggest that hydrogen is present at the surface of the hydrolysed sample.
Characterization of graphite‐supported platinum catalysts by electrochemical methods and XPS
Authors: De Bruijn F. A. , Marin G. B. , Niemantsverdriet J. W. , Visscher W. H. M. , Van Veen J. A. R. 
Published: December 2004

AbstractX‐ray photoelectron spectroscopy and cyclic voltammetry have been used to characterize 4.9 wt.% platinum‐on‐graphite catalysts used for the oxidation with molecular oxygen of methyl α‐D‐glucoside in aqueous solution. Cyclic voltammetry indicates that a surface oxidic layer is formed on the platinum particles upon exposure to ambient air. This oxidation could not be confirmed by XPS, however. The oxidation of methyl α‐D‐glucoside in the liquid phase is accompanied by growth of the platinum particles. Open‐circuit potential measurements indicated an increasing oxygen coverage of the platinum surface during reaction.
Characterization study of polycrystalline tin oxide surfaces before and after reduction in CO
Authors: Drawdy Jean E. , Hoflund Gar B. , Davidson Mark R. , Upchurch Billy T. , Schryer David R. 
Published: December 2004

AbstractPolycrystalline tin oxide surfaces have been examined before and after reduction in 40 Torr of CO at 100 and 175°C using Auger electron spectroscopy (AES), electron spectroscopy for chemical analysis (ESCA), ion‐scattering spectroscopy (ISS) and electron‐stimulated desorption (ESD). The changes in the surface composition and chemical states of the surface species generally are subtle for the reductive conditions used. Some of the SnO2 is reduced to SnO and significant changes do occur with regard to the amounts and chemical forms of the hydrogen‐containing species remaining after both the 100 and 175°C reductions.