bluuebunny/crossref_metadata_2025 huggingface dataset:
Interphase orientation of polyimide on polycrystalline gold, silver and Si(100)
Authors: Grunze M. , Hähner G. , Wöll Ch. , Schrepp W.
Published: May 2005

In this paper we present experimental data that can be used to infer the structural parameters of ultrathin polyimide films as a function of distance from the substrate surface. The polyimide films are prepared by the Langmuir‐Blodgett technique in a layer‐by‐layer fashion, and the orientation of the pyromellitimide unit in the polyimide macromolecules is determined as a function of film thick‐ness by near‐edge x‐ray absorption fine structure (NEXAFS) spectroscopy. To demonstrate that the interfacial bond determines the orientation of the polymer chains in the interphase, results for polyimide on gold, silver and Si(100) are compared.
Analysis of the polyolefin/trialkylamine primer interface
Authors: Yang D. Billy
Published: May 2005

Tertiary alkylamines of different chain lengths have been used as primers for adhesive bonding strength promotion for polyolefinic surfaces with cyanoacrylate (CA) adhesives. A combination of the construction of model polyolefin surfaces and advanced molecular‐sensitive analysis tools has been employed for understanding the promoter/polyolefin interaction at the interface. Characterization of primer structure and interfacial properties has been carried out using grazing angle reflection‐absorption Fourier transform infrared spectroscopy (GA/FTIR), ellipsometry, x‐ray photoelectron spectroscopy (XPS) and contact angle titration using different pH probe liquids. Our work has focused on the design and construction of a model polyolefin surface using a new in situ polyethylene (PE) polymerization technique to form a controllable thickness (<400 Å) of PE film on a reflective metal surface. The new technique of in situ PE polymerization is based on diazomethane chemistry. Both protonated and deuterated PE films have been successfully prepared. The results of spectroscopic investigations of these model deuterated and non‐deuterated PE surfaces are disclosed. Molecular parameters that affect adhesion promotion have been studied. The parameters studied include molecular structure and alkyl chain length of tertiary alkylamines.
The role of electron microscopy in the study of adhesion to aluminium substrates
Authors: Bishopp J. A. , Thompson G. E.
Published: May 2005

The analysis of the bondline in structural aluminium joints is taken as an example to illustrate how electron microscopy can be used to gain a new insight into the pheneomenon of adhesion. Scanning electron microscopy and transmission electron microscopy of ultramicrotomed sections has been used to characterize the adherend surfaces generated by the pretreatment processes prior to bonding. It is shown how a simple extension of these techniques can be used to analyse and characterize the interfacial and interphasial morphologies of the bonded joint both before and after exposure to ‘hot/wet’ environments. Results have shown that the importance of the so‐called mechanical interlocking phenomenon is related to the durability resistance of the joint rather than enhancement of the ‘dry‐state’ mechanical properties. It is also concluded that the formation of the voluminous hydrated alumina at the interface occurs post‐rupture and is not a prima facie cause. From the observed interphasial morphologies a hypothesis is advanced to explain the effect of various pretreatments on joint durability. Other analytical techniques, such as ‘parallel’ sections, AES, XPS and electron energy‐loss spectroscopy (EELS), are discussed and it is shown how these methods can be used, not only to confirm the interphasial structures but also to generate new data in their own right.

A Greater understanding, therefore, of the effect of adhesive theology, environmental exposure, adherend composition and pretreatment on the interface between adhesive and adherend, can be obtained using these techniques.
Growth of anodic oxides on reactively sputtered TiNx films
Authors: Montero I. , Jiménez C. , Albella J. M. , Perrière J.
Published: May 2005

The anodic oxidation behaviour of reactively sputtered titanium nitride thin films deposited onto silicon substrates has been investigated in order to obtain oxynitride layers at room temperature. It has been found that small differences in the stoichiometry of the titanium nitride films may give rise to large changes in the reactivity with oxygen. Thus, a strong influence of N/Ti atomic ratio value on the oxidation kinetics is observed. Analysis of the films by Rutherford backscattering and secondary ion mass spectroscopy reveals that the oxide structure is formed by an outer oxidized thin layer composed of a mixture of TiO2 + TiNx followed by a thicker layer with oxygen atoms dissolved in the previously deposited layer of titanium nitride. After prolonged oxidation, no nitrogen is detected in the surface layer, which is only composed of TiO2. Interestingly, the thickness of the outer layer is almost independent of the formation voltage and the anodization current.
A study of the chemical composition of some cobalt silicide layer structures
Authors: Greenwood J. C. , Lamb B. , Prutton M.
Published: May 2005

Auger and loss spectra and images have been obtained from a CoSi2 standard and a structure containing cobalt‐silicon films between a Co surface layer and a silicon substrate. The results from a Phi 590 spectrometer and the York MULSAM instrument have been compared. Quantitative analysis of the compositions of both samples has shown that elements can be used as standards along with well‐established matrix correction procedures. However, the effects of preferential sputtering in conventional depth profiling or bevel sectioning with ions lead to a complex composition distribution that is depleted in Si at the surface. The plasmon loss below the Co LVV Auger peak is enhanced in height near to the Si/silicide interface. The layer structure appears to be close to Co/Co2Si/CoSi/Si.
The application of surface imaging techniques to the study of pitting corrosion initiation in stainless steels
Authors: Baker M. A.
Published: May 2005

A combined Auger, EDX and SEM surface imaging study of the initial stages of pitting corrosion is presented. Examples of different pitting initiation situations are shown and the importance of multi‐technique imaging to interpret the results is demonstrated. The information provided by the images is compared with theories established primarily from electrochemical results. The development of scanning probe microscopies presents the opportunity of directly studying pitting initiation using imaging. Initial atomic force microscopy images of the corrosion of sulphide inclusions in stainless steels are given and the possible capabilities of the technique for application in this field are considered.
Vertical differential charging in monochromatized small spot X‐ray photoelectron spectroscopy
Authors: Yu Xiang‐Rong , Hantsche Harald
Published: May 2005

Differential charging (DC) is a charging effect in x‐ray photoelectron spectroscopy (XPS or ESCA) that results from the spatial variation of sample potentials in the XPS sampling volume. It can be conceptually categorized into two different aspects—lateral (LDC) and vertical (VDC)—according to the difference in the directions of the inhomogeneous distribution of the potentials in the surface phases of the sample. The phenomenon of VDC, which leads to a shift of the peak position, to a broadening of the peak width or even to a dramatic distortion of the peak shape, was observed in the following systems: semiconductors and conductors with ultrathin oxidized or insulating overlayers. The suggested approach to overcome the problem of VDC is simply to isolate the sample and neutralize it with electrons from a monoenergtic flood gun.
Description of the influence of elastic scattering of electrons in the specimen and in an adventitious hydrocarbon overlayer on photoelectron signals by effective values of the inelastic mean free path and the asymmetry parameter
Authors: Ebel H. , Ebel M. F. , Svagera R. , Pöhn C. , Jablonski A.
Published: May 2005

The influence of elastic scattering of photoelectrons in the substrate and in an adventitious hydrocarbon overlayer on the effective inelastic mean free path and the effective asymmetry parameter has been investigated by Monte Carlo calculation. The results are representative of 27 chemical elements, asymmetry parameters 0.6 ⩽ β ⩽ 2.0, kinetic electron energies 300 ⩽ Ekin ⩽ 1500 eV and overlayer thicknesses 0 ⩽ t ⩽ 26.6 Å. For an application in quantitative surface analysis by XPS we propose the use of the effective inelastic mean free path (0.951 IMFP, tabulated values) and the effective asymmetry parameter βeff. The calculation of βeff is performed by tabulated values of β, inelastic mean free paths and measured reduced thicknesses of the hydrocarbon layer.
Carbonization of candidate high‐temperature matrix materials for carbon/carbon composites
Authors: Pehrsson Pehr E. , Armistead Paul , Sastri Satya
Published: May 2005

Carbon precursors used for preparing carbon/carbon composite (CCC) matrix binders undergo component elimination and carbonization during heating, which affects the ultimate carbon product. We analyzed the structural and compositional changes of two polymeric precursors N,N′‐(1,3‐phenylenedimethylidene)bis(3‐ethynylaniline) and 4,4′‐bis(3,4‐dicyanophenoxy)biphenyl during high‐temperature annealing under inert atmosphere. The samples were analyzed using x‐ray diffraction, x‐ray photoelectron spectroscopy and microRaman scattering. The precursor molecules cross‐link during curing and annealing, to form glassy carbons. The carbon structure after the annealing was reflected by the high oxidizability of the carbon in air. Deconvolution of the C 1s and O 1s XPS spectra showed that the surface oxygen was present primarily as hydroxyl and carbonyl groups, and that the amounts of surface oxygen correlated with the extent of graphitization. Addition of iron in the form of ferrocene in the precursor accelerated graphitization at all temperatures. The results are compared to those for other polymer precursors and graphite.
Testing the success of analytical image correction routines: Surface images
Authors: Barkshire I. R. , Walton J. M. , Prutton M.
Published: May 2005

Multispectral techniques in Auger microscopy involve the acquisition of data as several spatially registered images or signals from the Auger, specimen absorption current, characteristic x‐ray, backscattered and secondary electron signals. Each signal contains information from different interactions and volumes within the sample. Various combinations of these signals can be used along with simple physical models to remove those contrast variations in Auger images that are not due to compositional variations of the sample within the Auger escape depth. Such contrast may, for example, be due to beam current fluctuations during data acquisition, substrate backscattering or topographical effects. To measure the success of these corrections, two tests have been devised: the calculation of the number of resolvable levels in the Auger image before and after correction; and the measurement of the modulus of correlation |CAR| between the corrected Auger image and the correction factor image. The tests may be used to evaluate any new image correction method. They have been applied to simulated and experimental data for a sample with varying subsurface composition. The results show that both tests are useful for evaluating the accuracy of a correction, and that measurement of |CAR| is the more sensitive test.
The application of chemical state AES and SAM to the examination of spray‐formed aluminium alloy fracture surfaces
Authors: Baker M. A. , Tsakiropoulos P.
Published: May 2005

The fracture surface of a spray‐formed Al‐5.2Cr‐1.4Zr alloy has been examined using AES and scanning Auger microscopy (SAM). Cratered regions of the surface were identified and high‐energy resolution AES analysis showed a localized 20 Å thick Al2O3 film to be present in these areas. Chemical‐state imaging of the Al fracture surface enabled the local distribution of oxide to be determined. The surface topography was not found to be suppressed using the standard (PB)/B or (PB)/(P + B) correction algorithms. This point is discussed with consideration of the electron emission from such highly structured surfaces. The oxide thickness measured from the craters is in good agreement with that previously determined by XPS for powder particles produced in the atomization process. Crater formation is suggested to occur as a result of complete powder particle solidification prior to the particles impacting the substrate/deposit. The localized oxide, revealed by fracture, presents areas of weakness in the unworked material.
Effects of crystallinity on depth resolution in sputter depth profiles
Authors: Hösler W. , Pamler W.
Published: May 2005

For sputter depth profiling the effect of the layer crystallinity on the resolution of the underlying interfaces was investigated. By applying D. Onderdelinden's model of monocrystal sputtering (Appl. Phys. Lett. 8, 189 (1966); Can. J. Phys. 46, 739 (1968)) and J. Lindhard's approach to axial ion channelling (Phys. Lett. 12, 126 (1965); K. Dan. Vidensk. Selsk. Mat. Fys. Medd. 34, No. 14 (1965)) to textured and non‐textured polycrystalline layers, it is shown that the interface resolution under these layers is largely affected by the channelling of incident ions. The strong dependence of channelling on the orientation of individual grains leads to extremely non‐uniform erosion and poor interface resolution. This model of polycrystalline layer sputtering reproduces well the dependence of depth profile shape and depth resolution on layer thickness, ion energy and incidence angle, as shown for sputter depth profiling through textured aluminium layers by inert gas ions. In the case of higher ion masses, the observed effects are slightly overestimated by the model, as anticipated from the inherent limitations of the Lindhard and the Onderdelinden approaches. The implications of channelling for depth profiles of polycrystalline layers are discussed and conclusions are drawn for appropriate selection of sputter parameters to ensure optimum depth resolution. The effects of sample temperature, continuous rotation of the sample during sputter erosion and reactive ion sputtering are also discussed.
Coincidence measurements in the electron spectroscopies: Surface studies
Authors: Thurgate S. M.
Published: May 2005

Coincidence techniques have been fruitfully employed in many areas of physics. They are now beginning to be used in the study of surfaces. In electron spectroscopy, their appeal is that they can be used to distinguish between processes, and, in some cases, to completely describe single events.

The interaction between surface atoms and electrons is complex, with many possible interactions. The coincidence technique can be used to reduce the number of possibilities and so to produce spectra that are more easily interpreted. However, the high density of atoms on a surface necessarily means that there is a high density of emitted inelastic electrons that appear as background in the spectra. These, and other effects, make it difficult to perform coincidence spectroscopy from surfaces, which explains why there have been relatively few experiments undertaken to date.

The progress in developing coincidence experiments is reviewed, along with a description of the understanding that has come from it.
Semiconductor surface layer analysis based on reflectometry
Authors: Jezierski K. , Misiewicz J. , Gumienny Z. , Heiman D.
Published: May 2005

An experimental set‐up for reflectance spectra measurements is presented. It is characterized by a high degree of precision, normal incidence of light and an energy range of 2‐6 eV. Computer analysis of the reflectance spectra is described. A multilayer model of the suface layer as well as the effective medium approximation theory are used. Results for implanted GaAs and for epilayers ZnSe/Zn3P2 are discussed.
SIMS Profile quantification by maximum entropy deconvolution
Authors: Allen P. N. , Dowsett M. G. , Collins R.
Published: May 2005

The action of the probe ions in SIMS depth profiling causes a number of mass transport phenomena. Consequently the data obtained are both broadened and shifted in a manner dependent on the species of the matrix, impurity and probe, and the experimental conditions. Quantification methods based on implanted standards and crater depth measurement are hampered by inaccuracies in the depth measurement, and take no account of the blurring processes. This paper reports the development of an alternative method. The blurring processes are not yet well enough understood for complete modelling. An empirical model, valid in the dilute limit, is that the true depth distribution is convoluted with an instrumental response to give the SIMS signal. If the response function is carefully defined, inversion of the convolution equation should give a fully quantified depth profile, correcting for blurring effects and any differential shift, mapping primary ion dose density (or time) back to depth and mapping signal intensity back to concentration in one mathematical operation. The sample from which the response function is measured becomes a complete concentration and depth standard. Deconvolution is non‐trivial as there is no unique solution in the real case, where the profile data and measured response consist of a finite number of data points. The method used here is based on the use of maximum entropy and returns the least biased (least structured) of the possible solutions. The use of this method to fully quantify two samples will be demonstrated and the results compared with ordinary quantification.
Enhanced SIMS analysis performance by CCl4 flooding technique
Authors: Gao Y. , Migeon H. N. , Juhel M. , Lecart J.
Published: May 2005

The CCl4 flooding technique combined with oxygen ion bombardment has been used during SIMS analysis. The secondary ion yield and the matrix effect have been investigated. The results have been compared with those obtained under oxygen bombardment or under oxygen bombardment plus oxygen flooding. We show that this simple technique allows a significant enhancement of ion yield for all the elements studied and induces a weak matrix effect.
Passive film composition and pitting behaviour of Fe–25Cr–11Nb studied by scanning Auger microscopy
Authors: Hubschmid C. , Mathieu H. J. , Landolt D.
Published: May 2005

Scanning Auger microscopy has been applied to the characterization of passive films formed on an Fe–25Cr–11Nb model alloy having a dendritic structure. The composition of the passive film is spatially non‐uniform and reflects the phase structure of the alloy. The Fe–25Cr–11Nb alloy exhibited a better resistance to pitting than a binary Fe–25Cr alloy. This is due to the fact that, on one hand, niobium improves the pitting resistance of the niobiumrich phase while, on the other hand, the pitting resistance of the niobium‐poor phase is enhanced by chromium segregation.
Quantification of SIMS data for multicomponent glasses
Authors: Bojan V. J. , Büyüklimanli T. H. , Pantano C. G.
Published: May 2005

Fracture and commercial float glass surfaces have been analyzed in a Cameca IMS‐3f spectrometer using 18O− bombardment. Sample charging was controlled through the use of different combinations of a gold grid and thin gold coating. Depth profiles have been quantified with relative sensitivity factors (RSFs) that were determined from fracture surfaces of float glasses of known composition. The sodium and potassium RSFs have been found to be more sensitive to the method of charge compensation than the RSFs of the other elements in the glass. The integrity of the sodium signal is not guaranteed by the presence of a grid on the sample surface. Depth profiles of fracture surfaces show unexpected gradients that can extend to 100 nm, complicating the interpretation of profiles obtained from manufactured surfaces. The calculation of the atomic fraction of all the elements in the glass is difficult within ∼300 nm of the surface owing to effects from the measured oxygen signal. Fortunately, the composition of the glass as expressed in mole percent of the oxides is more reliable, but still not free of artifacts. The results of these studies and those performed on similar glasses and materials in other laboratories suggest that, regardless of the primary beam, fracture surface analysis should precede the analyses of treated surfaces, especially if quantitative information is required within 100 nm of the surface.
On the applicability of tougaard background subtraction to general auger spectra
Authors: Bender Hugo
Published: May 2005

The Tougaard inelastic background subtraction algorithm is applied to the Auger spectra of a set of elemental standards including all kinds of Auger transitions. The problems occurring with certain transitions are discussed. The relative area sensitivity factors are calculated and compared with the sensitivity factors in differential mode and with theoretically calculated Auger yields. The relative sensitivity in direct mode using full peak integrations is larger than in differential mode. The experimental area sensitivity agrees remarkably well with theoretical predictions.
Auger electron angular distributions from Pt(111): The effect of adsorbed iodine monolayers
Authors: Doyle Charles A. , Chyan Oliver M. R. , Frank Douglas G. , Hubbard Arthur T.
Published: May 2005

Complete Auger electron angular distributions have been measured from a Pt(111) substrate in the presence and absence of three distinct iodine adlattices in order to investigate the effect of adsorbate layer structure on substrate emission. The adlattices investigated were Pt(111)(□3 × □3) R30°‐I, Pt(111)(□7 × □7)R19.1°‐I and Pt(111)(3 × 3)‐I. Three Pt Auger transitions were employed (65, 258 and 1968 eV) to explore the effect of Auger electron kinetic energy. For each kinetic energy investigated, the qualitative features of the substrate angular distributions were the same in the presence and absence of the iodine overlayer, although small quantitative differences were observed. An energy‐dependent quantitative effect was also observed, in which the absolute intensities of the distributions were attenuated substantially at lower kinetic energies but were relatively unaffected at higher kinetic energies. These results show that lower kinetic energy Auger electron angular distributions (<300 eV) are relatively sensitive to the presence of the adlattice, although careful quantitative measurements and analyses are required to observe the differences in the distributions. The origin of attenuation features in the distributions is not yet fully understood, and further experimental and theoretical development is required to relate the observed attenuation features to the surface structure.
Electronic structure and work function study of a model dispenser cathode surface
Authors: Lamouri A. , Krainsky I. L. , Müller W.
Published: May 2005

We have used work function measurements (Δϕ), Auger electron spectroscopy, low‐energy electron diffraction and angle‐resolved inverse photoelectron spectroscopy to study the coadsorption of barium and oxygen on tungsten. The experimental two‐dimensional band structure was compared with results of embedded cluster model calculations for a c(2 × 2) BaO monolayer on W(001) with barium and oxygen placed on alternate fourfold‐hollow sites. Our work function measurements revealed that adsorption of one monolayer of BaO decreased the work function of W(001) (ϕ = 4.63 eV) to ∼ 2.3–2.4 eV regardless of the order of barium and oxygen adsorption on the surface. Inverse photoelectron spectroscopy in the isochromat mode was used to investigate the unoccupied electronic energy levels of one monolayer of BaO on W(001) along two high‐symmetry directions of the W(001) surface Brillouin zone. Non‐dispersing spectral features were observed at 0.6 eV and 3.4 eV above the Fermi level (EF) and were assigned to transitions into both barium and tungsten d states in good agreement with calculated densities of states.
Maximum entropy quantification of SIMS depth profiles—behaviour as a function of primary ion energy
Authors: Allen P. N. , Dowsett M. G.
Published: May 2005

Previous publications have proposed the use of reconstruction as a method of quantification of SIMS depth profiles, taking the convolution integral as an approximate model for the measurement process in the dilute limit. We present here a demonstration of the maximum entropy (MaxEnt) reconstruction method for SIMS depth profile quantification at a number of primary ion energies. Neither implanted standard nor crater depth measurement are required by the technique, although both are used here as comparisons. The erosion rate calculated directly from the delta layer is found to be equivalent to that from crater depth measurement to within experimental accuracy. It is demonstrated that the MaxEnt reconstruction method can quantify a delta layer in ideal circumstances, remoing all energy‐dependent effects. For another sample (a set of three alleged delta layers) the MaxEnt reconstruction method is found to yield improvements in depth resolution at all energies, removing the energy dependence of the rise and decay slopes and almost halving the measured feature widths (full width at half‐maximum). This improvement in accuracy in quantification has enabled us to analyse more critically the sample, demonstrating that the layers had finite widths, a fact that was not evident from conventional quantification methods.
Characterization of a range of alkyl‐bonded silica HPLC stationary phases: XPS and ToF‐SIMS studies
Authors: Brown V. A. , Barrett D. A. , Shaw P. N. , Davies M. C. , Ritchie H. J. , Ross P. , Paul A. J. , Watts J. F.
Published: May 2005

A series of alkyl‐bonded silica HPLC stationary phases with a mean particle diameter of 5 μm has been prepared using a variety of dimethylalkylsilyl chlorides (i.e. monofunctional bonding agents) with alkyl chain lengths varying from C1 to C18, including phenyl and cyanopropyl groups. The stationary phases have been characterized using XPS and time‐of‐flight (ToF)‐SIMS. Elemental analyses by XPS have identified trace quantities of iron, sodium and chlorine at the silica/dimethylalkylsilyl chain interface, and aluminium was detected by ToF‐SIMS. A comparison of percentage carbon obtained by XPS with bulk carbon‐loading analyses suggests that the alkyl chains are bonded to the surface of the porous silica particles. Molecular ions characteristic of the dimethylalkylsilyl groups were identified in the ToF‐SIMS data together with ions attributable to these alkylsilyl groups attached to fragments of silica, the latter indicating covalent bonding to the silica surface. In addition, a series of low‐mass signals corresponding to alkyl chain fragments and silyl/silica‐based ions was observed. The value of high‐resolution ToF‐SIMS data for ion assignments is well demonstrated. The relative ion intensities of several of these low‐mass ions were studied as a function of changing alkyl chain length. In general, as the alkyl chain length increased, the abundance of the silicon‐containing fragments decreased, whilst the abundance of the alkyl‐based fragments increased, within the ToF‐SIMS spectra.
Comparative in situ ToF‐SIMS/XPS study of polystyrene modified by argon, oxygen and nitrogen plasmas
Authors: Petrat F. M. , Wolany D. , Schwede B. C. , Wiedmann L. , Benninghoven A.
Published: May 2005

The on‐line combination of time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) and monochromatized photoelectron spectroscopy is a valuable analytical tool for the characterization of chemically modified surfaces. By an in situ combination of these techniques with a plasma modification chamber, we have investigated polystyrene surfaces modified by various kinds of microwave plasmas (argon, oxygen and nitrogen).

The modified surfaces are widely different with respect to the incorporation of elements originating from the plasma, the degree of chemical changes caused by the plasma and the plasma‐induced etching rate. Significant formation of new functional groups specific for the plasma gas is only observed for nitrogen and oxygen. As compared to nitrogen and argon, treatment with the oxygen plasma leads to a high etching rate, but only moderate changes of the chemical state of the polymer surface. In all cases, severe degradation of the aromatic system occurs.

Exposure to air after plasma treatment leads to the uptake of considerable amounts of oxygen. In the case of the oxygen and argon plasma, the high mass resolution of ToF–SIMS allows the identification and distinction of clusters that are specific for the oxygen incorporated during plasma treatment and those appearing during exposure to the atmosphere.
E‐Beam SNMS: A complementary surface analysis technique
Authors: Bayly A. R. , Wolstenholme J. , Petts C. R.
Published: May 2005

Sputtered neutral mass spectrometry (SNMS) with ionization by low‐energy electron beam offers several analytical advantages that complement the capabilities of the major surface analysis techniques: XPS, AES and SIMS. These include easy operation on insulator specimens, reduced influence of topography or sample tilt, low spread of elemental relative sensitivity factors (RSFs) across the periodic table, near‐constant RSFs in different matrices and hence quantification from 100% down to trace concentrations, ppm detection limits, microprobe operation for depth profiling and submicron imaging and depth resolutions as for SIMS (≥1 nm). In addition to these analytical performances, the equipment shares much in common with quadrupole SIMS facilities and, as with that technique, is easily integrated into multitechnique instruments.

This paper compares performances of SNMS and SIMS on the same samples and presents some imaging and useful yield data from a close‐coupled ionizer, which is a new development on the 410 SIMSLAB. Comparisons are also made between, SIMS, SNMS and AES.
Segregation aspects at the fracture surfaces of 8 wt.% yttria‐zirconia thermal barrier coatings
Authors: Ingo Gabriel Maria , Padeletti Giuseppina
Published: May 2005

Small‐area x‐ray photoelectron spectroscopy (SAXPS), small‐area x‐ray‐induced Auger electron spectroscopy (SAXAES) and secondary ion mass spectrometry (SIMS) have been used to investigate segregation phenomena at fracture surfaces of 8 wt.% Y2O3–ZrO2 plasma‐sprayed thermal barrier coatings (TBCs) as a function of temperature up to 1620 K. The results show the complex microchemistry of the fracture surfaces, where segregation of bulk dissolved impurities such as Si, Al, Fe and Na and of the stablilizing yttrium oxide takes place from 1170 K. The SAXPS and SAXAES results indicate that the chemical composition of the segregated phase is ascribable to an infinite chain silicate of sodium with a variable presence of iron, yttrium and aluminium as a function of temperature. The SIMS ion images suggest, further, that aluminium and yttrium segregate both at the silicate segregated regions as well as separately. The effect of impurity segregation phenomena on the thermal shock resistance of the TBCs is discussed.
Factor analysis as a tool to deconvolute auger spectra of tungsten nitrides and carbides
Authors: Reniers F. , Hubin A. , Terryn H. , Vereecken J.
Published: May 2005

Factor analysis was applied to Auger sputter profiles of tungsten carbide and nitride samples. It is shown that very weak differences in the shapes of the metal peaks due to the presence of C and N can be isolated unambiguously by factor analysis. The different chemical states of carbon, nitrogen and tungsten were clearly identified.
Combined surface analytical and electrochemical study of the formation of passive layers on Fe/Cr alloys in 1 M NaOH
Authors: Hoppe H.‐W. , Haupt S. , Strehblow H.‐H.
Published: May 2005

Combined XPS and electrochemical studies of the passivation of Fe/Cr alloys have been performed in 1 M NaOH. Argon ion sputtering and a specimen transfer within a closed system provide a reliable situation with well‐controlled starting conditions for passivation transients and surface analytical studies with sufficient time resolution, especially at negative electrode potentials. The results for Fe/Cr are discussed on the basis of previous studies with the pure elements. The extremely slow dissolution of Cr(III) oxide and its relatively negative formation potential are responsible for the excellent passive behaviour of these alloys. Chromium(III) stabilizes Fe(II) and Fe(III) within the passive layer. Any Cr(III) enrichment is a consequence of preferential Fe dissolution. In 1 M NaOH the reduced solubility of Fe(III) oxide leads to an overlayer consisting mainly of Fe(III)oxide/hydroxide. The formation and oxidation of Fe(II) follows similar characteristics as found for oxide films on pure iron. Iron oxide components may, however, not be reduced to metal, as in the case of passive layers on pure Fe. These studies show that not only the final stationary state but also the process of passivation and the chemical changes of passive layers with potential and time can be investigated with XPS. Thus, one can obtain more reliable insight into the complicated processes leading to passivity.
Preparation of thin AlOx (0 ≤ x ≤ 1.5) films on gold and polycarbonate characterized by XPS, EPMA, AFM and TEM
Authors: Csanàdy A. , Pitton Y. , Mathieu H. J. , Kessler K. , Fuchs R. , Textor M.
Published: May 2005

The parameters controlling reactively deposited aluminium oxide films on Au and polycarbonate substrates have been investigated under typical PVD conditions of varying O2 flux and deposition rate of thicknesses up to 150 nm. Chemical and physical characterization have been carried out by the use of x‐ray photoelectron spectroscopy (XPS) combined either with sputter profiling or by variation of the emission angle (ARXPS), electron probe microanalysis (EPMA), atomic force microscopy (AFM) and by transmission electron microscopy (TEM). Correlation between XPS, EPMA, AFM and TEM points to island formation during co‐deposition of crystalline metallic Al and amorphous oxide areas if the O2 flux is insufficient. For high O2 fluxes, completely amorphous Al2O3 films are found. No intermediate phase between Al metal and Al2O3 was detected.
Effect of Ga+ backscattering in static SIMS
Authors: Zehnpfenning J. , Niehuis E. , Rulle H. , Benninghoven A.
Published: May 2005

We report on the origin of detected Ga+ ions in static SIMS measurements. The fraction of inelastically reflected Ga+ ions has been determined by applying primary ion pulses of two different gallium isotopes in appropriate time‐of‐flight (ToF) SIMS experiments. The fraction of backscattered and detected Ga+ ions is in the 10−3−10−6 range, depending on target material and surface contamination. The Ga+ signals observed in static SIMS experiments mainly originate from backscattered primary gallium ions.
Combined depth profile analysis with SNMS, SIMS and XPS: Preferential sputtering and oxygen transport in binary metal oxide multilayer systems
Authors: Albers Th. , Neumann M. , Lipinsky D. , Wiedmann L. , Benninghoven A.
Published: May 2005

Depth profile measurements of binary metal oxide multilayer systems have been performed by combined SIMS, SNMS and XPS. The combination of data about the particle fluxes and thus the bulk stoichiometry by SNMS, the ionic fluxes by SIMS, and the surface composition and the oxidation state of the metals by XPS provides a detailed insight into the mechanism of preferential sputtering in these systems. We present results on the systems Al2O3/TiO2 and SiO2/HfO2. The signal behaviour at the interfaces cannot be explained by preferential sputtering alone, but must include an oxygen transport mechanism due to chemical driving forces. By comparison of these systems with four other multilayer systems, we have developed a model of combined preferential sputtering and oxygen transport which accounts for the experimental results. The investigated systems can be classified according to their metal/oxygen sputter yield ratio, the degree of preferential sputtering, and the heat of formation of the oxide.
Crystalline effects on depth resolution in AES depth profiling
Authors: Kajiwara K.
Published: May 2005

An evaluation of the depth resolution of sputter‐assisted Auger electron spectroscopy (AES) has been studied for semiconductor superlattices. Zalar et al. have shown that sample rotation is effective in improving the depth resolution of AES depth profiling. Multilayers with two kinds of crystalline states were prepared to test the effectiveness of sample rotation. First, a microcrystalline Zr/Nb (10 nm/10 nm) multilayer was deposited by dc‐sputtering. Secondly, an AlAs/GaAs (10 nm/9 nm) and an InP/InGaAs (3 nm/3 nm) single crystalline superlattice were grown by metal‐organic chemical vapor deposition.

AES depth profiling with Ar+ ion sputtering was performed on these multilayers with and without sample rotation. Comparing the rotational depth profiling results with those obtained on stationary samples, it is found that, in the cases of the Zr/Nb and the InP/InGaAs multilayers, the depth resolution was considerably improved by sample rotation while in the case of AIAs/GaAs multilayer the depth resolution was only little improved by sample rotation. It is shown that the effectiveness of sample rotation strongly depends on the crystalline states of samples and on the degree of preferential sputtering.
XPS analysis of polypropylene grafted with acrylic monomers
Authors: de Lange P. J. , Gebben B. , Elfrink P. J.
Published: May 2005

X‐ray photoelectron spectroscopy (XPS) has been used to characterize the surface of nonwoven polypropylene grafted with acrylic monomers. Results obtained for the non‐ionic hydroxyethyl methacrylate (HEMA) and 2,3‐dihydroxypropyl methacrylate (DHPMA) are very clear and in agreement with those of CWST (critical wetting surface tension) measurements. Estimation of the thickness of the grafted layer from the XPS measurements is consistent with results from a simple theoretical calculation. The results obtained for the ionic methacrylic acid (MAA) deviate and are not in agreement with those of the CWST measurements. This is not understood, but might be attributed to the folding of the more polar MAA chains under dry conditions, leading to incomplete coverage of the surface. A second explanation is a higher contribution of grafting in the bulk of the polymer. Both explanations are supported by grafting of MAA from methanol as solvent.
Argon bombardment‐induced topography development on InP
Authors: Malherbe J. B. , van der Berg N. G.
Published: May 2005

InP (100) samples, n‐doped with S atoms to 4 × 1018 cm−3 and to 6 × 1018 cm−3, were bombarded by low energy (0.5 to 5 keV) argon ions. After bombardment, the surfaces exhibited the formation of small protrusions on the surface. These sputter cones appeared after an ion dose of the order of 1015 Ar+ cm−2. These cones grow slowly with increasing ion dose. At a constant dose, the sizes and density of these cones depended on the angle of incidence of the argon ions. At an ion incidence angle of approximately 41°, a maximum was obtained in the topography development. The sputter‐induced morphology had, at a constant dose density and angle of incidence, only a slight dependence on the energy of ions in the 0.5 to 5 keV range. Sputtering at the two lower energies (0.5 and 1 keV) resulted in an increase in the surface roughness compared to the higher ion energies. No synergic effects of simultaneous electron and ion bombardment were observed in the as‐factory received samples. When the angle of incidence of the bombarding ions was kept fixed, the degree of sputter‐induced surface topography remained constant for different relative orientations of the (100) InP substrates. Seeding cones were observed under appropriate conditions, but were not systematically investigated.
Investigation of thin films by soft X‐ray fluorescence and by total electron yield measurements
Authors: Ebel H. , Mantler M. , Svagera R. , Kaitna R.
Published: May 2005

We propose a description of the sampling depth (λ) of total electron yield experiments (TEY) in terms of kinetic Auger electron energies. This empirical response results from literature data1 – 6 on low energy (<2 keV) and from our own experiments performed on thin layers of Cu on Fe substrates and on thin layers of AlxGa1 − xAs on GaAs substrates at energies of approximately 5to 8 keV. From these investigations we estimate a sampling depth of 74 nm for Ga KLL Auger electrons in AlxGa1 − xAs. For comparison, the sampling depth of x‐ray fluorescence analysis (XRF) for Al Kα radiation in AlxGa1 − xAs is 400 nm.

Both methods (XRF and TEY) were joined for quantitative determination of the thickness t and the Al content x in thin AlxGa1 − xAs layers on GaAs substrates. Al Kα fluorescence radiation excited by polychromatic x‐radiation and the jump of the total electron yield in the vicinity of the GaK‐edge were used in our analytical model. The validity of this model is verified by a comparison of our results with the expected values (known from preparation of the layers).
The growth mode of copper and iron for the Cu/Fe and Fe/Cu interfaces
Authors: Polzonetti G. , Di Castro V. , Furlani C.
Published: May 2005

The early stages of Cu and Fe metal growth on respectively Fe and Cu polycrystalline substrates have been studied at room temperature by photoemission spectroscopy. Analysis of the Cu3p and Fe3p core levels peaks intensity as a function of the metal overlayer coverages has been made for both systems. Formation of the first atomic layer followed by clusters aggregation has been detected as the mode of growth for Cu on Fe as well as for Fe on Cu. Previous results obtained by UV‐photoemission have been confirmed with the evidence for the absence of interdiffusion and surface alloy formation at the interface.
XPS and AES study of Al2O3/Ti6Al4V interface: Influence of oxidation and nitruration of the metal surface
Authors: Delogu P. , Dikonimos‐Makris T. , Giorgi R. , Lascovich J. , Caneve L. , Scaglione S.
Published: May 2005

Important properties of the coating/substrate combination like hardness, stress and, in particular, adhesion rely partly on the morphology and microstructure of the interface, which is often physically and chemically different from the substrate as well as from the coating.

The aim of this work is to study the influence of the chemical state of the metal surface on the structure of the interface Al2O3/Ti6Al4V, obtained by deposition via sputtering of the ceramic.

For this purpose three different surface treatments of the substrate were performed: air oxidation, cleaning by Ar+ sputtering and nitrogen ion implantation.

The chemical composition of the treated surfaces was assessed by x‐ray photoelectron spectroscopy, while the composition of the interfaces was investigated by Auger electron spectroscopy depth profiling.
Surface structure of the PAN‐based carbon fibres studied by the scanning probe microscopy (SPM)
Authors: Zhdan P. A. , Grey D. , Castle J. E.
Published: May 2005

Scanning tunnelling microscopy (STM) and scanning force microscopy (SFM) have been applied to characterize the surface topography of carbon fibres before and after activating electrochemical treatment. Electrochemical activation is seen to have a significant effect on the structure of the surface layers. The influence of scanning parameters on STM and SFM images was examined and it was found that alteration of the scanning direction allows important additional information about surface structure of carbon fibres to be obtained. It also makes it possible to estimate the contribution of the artefacts to resulting images. The results indicate the great potential of both STM and SFM for three‐dimensional surface characterization of carbon fibres.
STM characterization of InP gratings for DFB laser fabrication
Authors: Meneghini G. , Picotto G. B. , Gentili M. , Grella L.
Published: May 2005

Diffraction gratings for distributed feedback (DFB) laser devices were characterized by means of a scanning tunnelling microscope (STM) operating in air. The gratings, made of n‐doped InP semiconductor, were prepared using holographic and electron beam lithography (EBL) exposures followed by reactive ion etching (RIE) to transfer the photoresist pattern into the wafer. The grating surfaces were partly shadow‐coated with a thin gold layer, and the line patterns were STM‐imaged on both the coated and non‐coated InP surfaces. Pitches of first‐ and second‐order gratings, including λ/4 phase shift lines and the depth of the holographic second‐order grating, were measured by means of a precisely calibrated piezo‐capacitive STM head, a UV diffractometer and a scanning electron microscope (SEM). A precise STM characterization of the coated line patterns was achieved. As regards the non‐coated surfaces, reliable STM measurements of InP grating pitches were performed without any sample preparation and surface contamination.
Identification of the fixed nitrogen containing species during the photo‐oxidative fixation of molecular nitrogen on UV‐illuminated TiO2surfaces
Authors: Navio J. A. , Real C. , Bickley R. I.
Published: May 2005

Ultraviolet photoexcitation of hydroxylated TiO2surfaces in the presence of a mixture on N2/O2gas (air) produces some adsorbed nitrogen oxide species which were previously assigned indirectly as probably N2O22−. Direct assignment is now reported here. From comparisons of the thermodesorption profiles and the XPS results from polycrystalline Na2N2O2and from the corresponding data obtained from TiO2surface upon which Na2N2O2had been allowed to adsorb with the thermodesorption profile and XPS data obtained from the photo‐induced fixation of nitrogen on TiO2, it can be concluded that the principal species formed during the photo‐oxidative fixation of molecular nitrogen on TiO2is hyponitrite anion, N2O22−.
Use of ion implantation to study the corrosion of an austenitic steel in an oxidizing/sulphidizing atmosphere
Authors: Stroosnijder M. F. , Norton J. F.
Published: May 2005

The beneficial effect of the addition by ion implantation of cerium on the corrosion behaviour of a 32Ni‐20Cr austenitic steel in a mixed oxidizing/sulphidizing environment, at 700 °C has been studied. Emphasis was placed on the initial stages of the corrosion process using a wide range of surface analytical techniques. Comparison is made with unimplanted material and also with xenon‐ and chromium‐implanted steel. The latter had no significant effect. In contrast Ce ion implantation improved the corrosion behaviour, which is probably due to a change in the nucleation stage of corrosion, leading to an improved quality of the oxide layer forming under the initial corrosion products. Factors which might contribute to this are discussed.
Application of reflectance spectrophotometry to the study of copper (I) oxides (Cu2O and Cu3O2) on metallic substrate
Authors: Lefez B. , Kartouni K. , Lenglet M. , Rönnow D. , Ribbing C. G.
Published: May 2005

The aim of this study is to characterize the compounds grown on copper during the oxidation at low temperature (T < 523 K) by optical methods: photoluminescence and UV‐Visible‐NIR diffuse reflectance spectroscopy. Two cuprous oxides Cu2O and Cu3O2 have been studied. The absorption of Cu2O films in the range 450–630 nm is mainly due to non‐stoichiometry bands associated with copper and oxygen vacancies. Cu3O2 is characterized by an optical band gap greater than that of Cu2O (respectively 2.25 and 1.95 eV) and by an intense luminescence emission at 760–780 nm. Cu3O2 may be considered as a gross defect structure of Cu2O (a = 0.427 nm, a = 0.431 nm). The experimental approach of the oxidation mechanism reveals that at 423 K Cu2O is the primary product which later on is transformed into Cu3O2. Experimental and calculated optical absorption curves disclose the nucleation of CuO inside the cuprous oxides layer for oxidation in the range 473–523 K.