bluuebunny/crossref_metadata_2025_split huggingface dataset:
A new approach to surface energy characterization for adhesive performance prediction
Authors: Penn L. S. , Bowler E. R. 
Published: December 2004

AbstractA new approach to qualitatively predicting adhesion at a solid/solid interface is described. It is based on thermodynamic compatibility of the two adhering surfaces, but it overcomes the weaknesses of existing methods by using a full set of contact angle data and by assembling the data to reveal the main features of the set without loss of information. Adhesive performance data to support this approach are presented.
A contribution to the investigation of enamel/metal Interfaces
Authors: Baumgartl S. , Warnecke W. , Holm R. 
Published: December 2004

AbstractThe diffusion processes which influence the adhesion between enamel and metals take place in an ∼5 μm thick layer at the interface. Electron X‐ray microanalysis cannot be used to investigate this zone, except to a limited extent, because its depth and lateral resolution are inadequate. A procedure which permits quantitative determination of Fe in the zone at the interface is described. It is based on X‐ray and Auger microanalysis of tapered sections. The Auger intensities are quantified by X‐ray microanalysis within sufficiently thick enamel layers.
Interfacial reactions between Al and RuO2, MoOx and WNx diffusion barriers on Si
Authors: Hörnström S. E. , Charai A. , Thomas O. , Krusin‐Elbaum L. , Fryer P. M. , Harper J. M. E. , Gong S. , Robertsson A. 
Published: December 2004

AbstractThe Interfacial reactions between Al and RuO2, MoOx and WNx diffusion barriers on Si (100) wafers have been studied. The diffusion barrier structures were analyzed before and after various heat treatments using Auger electron spectroscopy (AES) and cross‐sectional transmission electron microscopy (XTEM). Al was found to reduce the oxides of both Ru and Mo. A 100 Å thick Al2O3 layer developed between the Al and the RuO2 films during annealing at 500°C for 30 minutes. The formation of interfacial Al2O3 efficiently prevents Al penetration but may cause a too high contact resistance for applications in contact structures of microelectronic devices. The WNx barrier was stable after annealing at 600°C for 30 minutes, if the film was exposed to air prior to Al deposition. If, instead, the Al was deposited in situ, the structure failed after annealing at 500°C due to a reaction between Al and W giving WAl12. A thin Al2O3 layer was detected between the Al and the WNx films of the air exposed sample. This layer had the effect of retarding the Al–W reaction and thereby raised the failure temperature of the barrier by at least 100°C.
Characterization of electrodeposited metals using continuous‐wave optical second‐harmonic generation
Authors: Miragliotta J. , Furtak T. E. 
Published: December 2004

AbstractThe optical polarization properties of second‐harmonic generation at normal incidence have been used to characterize the symmetry of electrodeposited monolayers of zinc and thallium on Ag(111) while the sample was under electrochemical control. Our technique involves a non‐conventional‐wave method with standard weak optical signal detection. The overlayers exhibit a strongly bound monolayer phase that can be experimentally separated from the multilayer growth condition. Both metals grow with a C3v symmetry that is aligned with the substrate at low coverage. This is maintained for higher coverages in the case of Tl but changes for Zn. These results are consistent with an epitaxial 8.6% expanded hexagonal monolayer for Zn, followed by a return to the Zn lattice constant at higher coverage. However, we propose that Tl grows with a coincidence lattice that is (6 × 6)–25 Tl for all coverages studied in this experiment (up to five layers).
Electrochemical and XPS evidence of the aqueous formation of Mo2O5
Authors: Clayton C. R. , Lu Y. C. 
Published: December 2004

AbstractXPS was employed to detect the surface species deposited on an activated platinum electrode following cathodic polarization in deaerated 0.1 M (NH4)6Mo7O24 · 4H2O solution. At – 160 mV (saturated calomel electrode, SCE), evidence was found of the possible dissociation of polymolybdate to molybdate with subsequent surface adsorption. At –340 mV (SCE) molybdate was observed to reduce to Mo5+ in the form of Mo2O5. At – 540 mV (SCE), Mo4+ was the stable species, existing in the form of tetravalent oxyhydroxide MoO(OH)2 according to XPS analysis. No further reduction from Mo4+ to lower‐valent states was observed when cathodically polarized to – 900 mV (SCE). Mo2O5 was found to be unstable in air, oxidizing readily to MoO3.
Applications of secondary neutral mass spectrometry (SNMS) in VLSI technology
Authors: Anderle Mariano , Moro Lorenza 
Published: December 2004

AbstractSecondary neutral mass spectrometry (SNMS) is a promising analytical technique for the characterization of thin films and bulk samples. We applied this technique to thin films used in VLSI technology.The samples investigated ranged from sputter‐deposited Al alloy films used as long‐range interconnections, to silicide or silicide/polysilicon structures for gate interconnections, to dielectric films and doped silicon dioxide glasses used for insulation and passivation purposes. In all these samples the distribution of the elements was studied as a function of deposition and/or annealing conditions.The SNMS results are compared with those obtained by more common analytical techniques, such as SIMS and nuclear analyses (RBS and nuclear reaction analysis). This comparison emphasizes the features of SNMS: good depth information, less sensitivity to matrix effects and optimum depth resolution.
Optical properties of titanium nitride thin films
Authors: Tompkins Harland G. , Gregory Richard , Boeck Bruce 
Published: December 2004

AbstractTitanium nitride films were deposited using various process parameters. The film stoichiomtery and the optical properties were than measured for all of the films. As expected, the stoichiometry is affected by the deposition rate and composition of the gas phase. We show that the index of refraction is affected by the substrate temperature as well as by the stoichiometry. We also show that as long as the amount of nitrogen in the film is above a critical value, the film is nitride‐like. When the amount of nitrogen in the film drops below a critical value, the index of refraction is more characteristic of metallic titanium than titanium nitride.
Oxide formation on Fe and Ti thin films and on Fe thin films modified with ultrathin layers of Ti
Authors: Lee Paul A. , Stork Kurt F. , Maschhoff Brian L. , Nebesny Ken W. , Armstrog Neal R. 
Published: December 2004

AbstractReactions of O2 and H2O to from thin oxides on Fe, Ti and Ti‐modified Fe thin films have been studied by XPS, following O2 and H2O exposure in the range 0‐600 L, to form oxides with thicknesses of < 40 Å. XPS Iineshape analysis is used, utilizing a special combination of reflection electron energy‐loss spectroscopy (REELS) and nonlinear least‐squares fitting routines to model the intrinsic and extrinsic energy losses that accompany potoemission for the Ti and Fe 2p lines. During the formation of the thinnest oxides, this approach yields a unique picture of the composition of the oxide, while for the thicker layers, there is little significant difference between this fitting approach and (1) fitting approaches using an integral background approach or (2) direct deconvolution methods using the REELS data. Both Fe and Ti are quite reactive to O2, yielding a surface oxide that is apparently an FeO‐dominated FeO/Fe3O4 bilayer on Fe surface oxide that is predominantly TiO2 on the Ti surface. Pure Fe and Ti surfaces are unreactive to H2O. Predosing of thewse surfaces with low levels of O2 (5 L) does not increase the reactivity appreciably toward H2O. Ti dispersed on the Fe surface as an adatom layer, with an equivalent thickness of 3 Å, greatly suppresses the reactivity of Fe toward O2, while the Ti is oxidized primarily to TiO2, In contrast to the pure Ti layers, these Ti adatom layers are quite reactive toward H2O, yielding oxides (no evidence for hydroxide) in a uniform distribution of oxidation states (Ti+2, Ti+3 and Ti+4).
Oxidation mechanisms on α‐brasses (10 and 30 at.% Zn) by optical methods and SIMS
Authors: Beucher E. , Lenglet M. , Weber S. , Scherrer S. 
Published: December 2004

AbstractOptical methods—Fourier transform infrared spectroscopy, ultraviolet‐visible‐near‐infrared spectroscopy (UV‐Vis‐NIR)—are used to control the oxidation products grown on the surface of cold‐worked α‐brasse (10 and 30 at.% zinc). The influence of sample preparation (mechanical polishing and chemical cleanings) on oxidation rates is also studied. The duplex oxide scale (copper oxides on the top of the layer and zinc oxide at the metal/oxide interface) obtained during brass oxidation and perfectly exhibited by SIMS depth profiles can be explained in terms of internal oxidation and of the semiconductor properties of ZnO and Cu2O.
Some Applications of high‐energy, high‐resolution Auger electron spectroscopy using bremsstrahlung radiation
Authors: Kövér L. , Varga D. , Cserny I. , Tóth J. , Tökési K. 
Published: December 2004

AbstractContinuous energy distribution x‐rays obtained from a high‐voltage (20–30 kV) source with an Mo anode were used for exciting Si KLL, S KLL, Ag LMM and Mn KLL Auger transitions in the 1.5–5.5 keV kinetic energy range. X‐ray‐induced AES measurements were performed by a new, high‐energy electron spectrometer demonstrating the obtainable resolution and the considerable gain in intensity in comparison with previous results.
The intrinsic redox states in polypyrrole and polyaniline: A comparative study by XPS
Authors: Kang E. T. , Neoh K. G. , Tan K. L. 
Published: December 2004

AbstractX‐ray photoelectron spectroscopy provides a useful tool for the critical comparison of the chemical nature of the nitrogens corresponding to the various intrinsic redox states of electroactive polypyrrole (PPY) and polyaniline (PAN) and their N‐substituted derivatives. Proton modifications of the PPY nitrogens can give rise to a number of intrinsic redox states corresponding to various proportions of the imine‐like (N) and amine‐like (NH) nitrogens, similar to those observed in PAN. For complexes prepared from oxidative polymerizations, the intrinsic oxidation level of PAN is always about twice that of PPY (50% vs. 25%). The behaviours of the nitrogens of the corresponding redox states in both polymers towards oxidation, reduction, protonation and charge transfer interactions are grossly similar. However, the amine nitrogens in the emeraldine (EM) oxidation state of PAN (50% N structure) are more susceptible to protonation in the presence of excess protonic acids than those of the 25% deprotonated PPY (DP‐PPY). Finally, the doping level in poly(N‐methylaniline) (PMAN) is twice that of poly(N‐methylpyrrole) (PMPY). The base polymers of PMAN and PMPY exist only in the fully reduced state and are susceptible to reoxidation. The nitrogens of PMAN, but not PMPY, are also susceptible to protonation.
XPS study of pumice‐supported palladium and platinum catalysts
Authors: Venezia A. M. , Duca D. , Floriano M. A. , Deganello G. , Rossi A. 
Published: December 2004

AbstractAn XPS study has been performed on samples of monometallic catalysts of palladium and platinum and on bimetallic Pd‐Pt catalysts supported on pumice. A negative shift of about 0.5 eV in the Pd 3d and Pt 4f binding energies of the catalysts relative to the energies of the same levels in the pure metals suggested an increase in the electron density in both metals. A quantitative XPS analysis indicated that the supported metals did not modify the surface atomic composition of pumice. In the bimetallic catalysts the variation in the Pd 3d/Pd MNN intensity ratio over the different Pd/Pt atomic fractions has been attributed to surface segregation of the metal present in smaller amount.
Catalytic oxidation of Mo by caesium oxides
Authors: Soriano L. , Trigo J. F. , Galán L. , Rueda F. 
Published: December 2004

AbstractThe oxidation of a clean Mo surface with different caesium oxide overlayers has been studied by means of x‐ray photoelectron spectroscopy. The results show that the presence of a caesium oxide overlayer produces enhanced oxidation of Mo at room temperature when compared with thermal oxidation, and that a layer of MoO3 is formed on top of the Mo substrate. The thickness of this MoO3 layer depends on the thickness of the caesium oxide overlayer. Also, true catalytic oxidation has been observed when the substrate with the caesium oxide overlayer is exposed to oxygen at room temperature. The interface of the MoO3 layer with the Mo metal consists of about five monolayers of Mo suboxide MoOx (with x ∼2) when the oxidation has been performed at room temperature. At moderate temperatures (∼400 K) this interface is smoother, although it tends to decrease in thickness with time. A mechanism of catalytic oxidation that is consistent with the experimental data is proposed. This mechanism is controlled by diffusion of oxygen through the caesium oxide overlayers and through the Mo substrate. Also, a diffusion of Cs towards the surface has been detected. Different phases of the type MoO3−δ can explain the chemical shifts observed in the Mo6+ XPS spectra.
Fine structure of supported and promoted catalysts as deduced from XPS intensity data
Authors: Praliaud H. , Martin G. A. , Fenyvesi J. , Somogyi I. , Varsányi G. , Mink G. 
Published: December 2004

AbstractFor model calculations it is assumed that metal spheroids are randomly distributed on spherical support particles of nearly closest‐packed arrangement. Both the metal and the support can be covered with layers or submonolayers of promoter(s) and carbon. The average diameters as well as n, the average number of metal particles on one support sphere, are estimated from total surface area and selective chemisorption measurements and preferably by electron microscopy too. In the computer programme two cases are distinguished depending on whether n < 4 or n > 4, since in the latter case the partial shadowing of coated metal particles by others should also be considered. Electron beams emitted by the metal, the support and their layers are calculated as a function of the ‘angle of latitude’ of the support spheres and the ‘angle of latitude and longitude’ of the metal spheroids. The computation variables are the thickness and sequence of different layers above the metal and the support, the extent of ‘immersion’ of metal particles into the support and/or its layers and the extent of diffusion of promotor cations into the support matrix. The calculated intensities are compared with the measured ones. By this method the probable fine structure of an alkali‐promoted Pd/SiO2 (n < 4) and a sodium‐promoted Ni/(Al2O3 + SiO2) catalyst (n > 4) has been determined.
A new formalism for angle‐resolved X‐ray photoelectron spectroscopy (ARXPS) and Auger electron spectroscopy (ARAES) of non‐crystalline solids taking elastic electron scattering into account
Authors: Werner W. S. M. , Störi H. 
Published: December 2004

AbstractThe effects of elastic electron scattering in non‐crystalline solids on the angle‐resolved mode of the electron spectroscopic techniques have been studied with a Monte Carlo model. The results of this study demonstrate that elastic scattering must be accounted for in the formalism of angle‐resolved Auger electron spectroscopy and angle‐resolved x‐ray photoelectron spectroscopy. The use of a recently introduced attenuation law for signal electrons in the angle‐resolved electron spectroscopies is studied. The effects of elastic scattering are incorporated in this attenuation law by the use of one additional parameter that depends on the energy and the material. This parameter, the so‐called attenuation parameter, can be found in the literature.It was found that this new attenuation law yields an accurate description of the influence of elastic scattering on the angular distribution of signal electrons, which is by far superior to the straight‐line approximation. Neglecting the influence of elastic scattering introduces an error of ∼50% in the calculated overlayer thicknesses. The conventional algorithms to restore depth profiles from angle‐resolved experiments can be modified easily to account for elastic scattering through the use of the new attenuation law. This yields restored thicknesses which agree within 1% with the model thickness.Another important finding of this study for the angle‐resolved electron spectroscopies is that elastic scattering poses a strict upper limit to the depth range that can be analysed by means of angle‐resolved measurements.
Background correction in XPS: Comparison of validity of different methods
Authors: Tougaard S. , Jansson C. 
Published: December 2004

AbstractWe investigate the validity of methods for background correction in XPS by comparing determined peak intensity ratios with theory. For Ag, Pt and Au, peaks are considered for which possible errors in the inelastic electron mean free path and in the energy dependence of the analyser response function have minimal influence on the accuracy of the theoretical ratios. The straight line method gives a root‐mean‐square (RMS) deviation from theory of ∼34% and ∼60% when the low‐energy point is selected to lie close to or far from the main structure of the peak respectively. The Shirley method gives an RMS deviation from theory of ∼35%, with only a small change between two sets of considered energy ranges. The Tougaard method gives an RMS deviation from theory of ∼3%, which is of the order of the expected uncertainty due to the combined effects of the level of the apparatus stability and the errors in the ratios of photo‐ionization cross‐sections.
Quantitative depth profiling of nitrogen‐implanted titanium by use of Auger electron spectroscopy and subsequent target factor analysis
Authors: Bubert H. , Mucha A. 
Published: December 2004

AbstractTitanium samples were implanted with N+ and N2+ ions of an energy of 80 keV and an ion dose between 1017 and 1018 atoms cm−2, which led to near‐surface nitrogen‐containing coatings. Auger depth profiles were taken from these coatings and the gathered data were subjected to target factor analysis. As a main result, three components could be detected and assigned to metallic Ti, TiN and a hitherto unknown Ti/N component, the atomic concentration ratio of which was estimated to be Ti:N ≈︁ 1:1.15. Thereby, the atomic concentration depth profiles could be calculated, resulting in the stoichiometry of titanium nitride at an implantation dose from 5 × 1017 N+ cm−2 upwards. A relationship between the ion implantation dose and the wear resistance of the coatings could not be corroborated by the measurements.
Auger backscattering factor at primary beam energies above 10 keV
Authors: Merlet C. , Jbara O. , Rondot S. , Cazaux J. 
Published: December 2004

AbstractTaking into account the identity of the ionization function of electron probe microanalysis (EPMA) at the surface, Φ(0), and the Auger backscattering factor, r, new results and a compilation of published results are reported for the determination of r [or Φ(0)] obtained at normal incidence and at primary beam energies Eo above 10 keV.The 79 experimental values thus obtained have been compared to the functional expressions proposed by Love and Scott, by Merlet [both for Φ(0)] and by Shimizu for r, leading to standard deviations of 11.3, 8.6 and 10.8%, respectively. At last, a deviation of 8.4% has been obtained when the experimental results are compared to a functional expression involving only the element of interest, Z1, at the surface and the electron backscattering factor, η, of the substrate. The advantage of this last approach is that it can be applied to correct automatically the backscattering effects of the Auger images and of the Auger depth profiles by the simultaneous measurement of η with a calibrated backscattered electron detector, but without the knowledge of the (changing) bulk composition.
Composition of oxides and nitrides from line shapes of metal core level x‐ray photoelectron spectra
Authors: Galán L. , Prieto P. , Morant C. , Soriano L. , Sanz J. M. , Elizalde E. , Rueda F. 
Published: December 2004

AbstractA method is proposed which evaluates the averaged composition of a sample in terms of the centroid of the core level XP spectrum. The method is based on the basic principle of electron spectroscopy for chemical analysis, i.e. the additive property of the chemical shifts and their proportionality to the ligand co‐ordination. It allows one to calculate the averaged composition of compounds if the line shapes of spectra corresponding to stoichiometric samples (including the pure metal) are known and a few simple conditions are assumed. The main advantage of this method is that the composition can be obtained even if the individual contributions of the different oxidation states cannot be resolved or deconvoluted, so that no previous knowledge of the oxidation states or co‐ordination structure is necessary. This method of calculating the composition is illustrated by its application to ZrOx, HfOx, NbNx, TaNxOy and SiNxOy obtained by different methods. The results are then compared with those obtained from the usual XPS quantitative analysis, so that further insight to the sample near‐surface structure and composition can be gained by this combined study.
Quantitative analysis of reflection electron energy‐loss spectra
Authors: Yubero F. , Tougaard S. 
Published: December 2004

AbstractIt is shown that a quantitative description of the energy‐loss processes in a reflection electron energy‐loss spectroscopy (REELS) experiment cannot be obtained from a simple linear combination of pure bulk and pure surface components. A quantitative description can, however, be obtained within the dielectric response formalism for a more realistic model which takes into account the physical conditions in a REELS experiment.
Silicon ion bombardment of Sb/Si contacts
Authors: Malherbe J. B. , Friedland E. , Bredell L. J. , Fletcher M. , Weimer K. P. 
Published: December 2004

AbstractSi+ bombardment of Sb/n‐Si Schottky contacts significantly affects the values of some Schottky parameters even at low does densities. The parameters considered are the ideality constant n, the saturation current density Is and the series resistance R. Before implantation these parameters exhibited large variations due to interface conditions. After implantation more uniform I–V characteristics were observed. Implantation led to higher values for the ideality constant and the series resistance and lower values for the saturation current. The ideality factor showed a decrease with increasing implantation dose. The saturation current and series resistance did not show any dose dependence. The compositional/structural properties of the contacts after ion bombardment are altered at high dose densities. For dose densities ϕ ≥ 5 × 1014 Si+ cm−2, α‐particle channelling showed the silicon substrate to be partly amorphized. This amorphization increased with increasing dose densities. AES and RBS measurements found no evidence of silicide formation. Only slight mixing was observed. Other experimental and theoretical studies either confirm our measurements or confirm the trend of our measurements.