bluuebunny/crossref_metadata_2025 huggingface dataset:
Noble gas depth profiles in amorphous TiO2 films after sputtering
Authors: Wolff M. , Schultze J. W.
Published: May 2005

TiO2 films are formed galvanostatically in 1 N H2SO4 by anodic polarization. The resulting amorphous oxide layer is about 30 nm thick. The films are sputtered with Ne+, and Kr+ in the energy range from 2 to 9 keV. This sputter process is always combined with an implantation of the sputter ions in a partially reduced oxide. The distribution of penetration depth (1−10 nm) of implanted noble gas ions is investigated by two methods. In the top few nanometres it is derived from angle‐resolved X‐ray photoelectron spectroscopy measurements. The obtained results can be assigned approximately to a two‐layer model with an inner implantation layer (d1 = 10 nm, cAr = 10–25%) and a gas‐free surface layer (dGF = 0.5–2 nm) owing to diffusion and outgassing of the implanted noble gas ions. On the other hand, we carried out Kr+ sputter profiles of TiO2 implanted with Ar+ and Ne+ by previous sputtering. This yields an immediate decrease of the previous sputter gas (Ar, Ne) concentration which is explained by fast diffusion of Ar and Ne induced by the high temperatures during the Kr+ sputtering.
Surface segregated boron nitride on a FeSi alloy: Thermal oxidation and related segregation phenomena
Authors: Humbert P. , Essouni M. , Mosser A.
Published: May 2005

The surface of a Fe‐3.1 wt% Si single crystal, containing boron, nitrogen, sulphur and carbon in the ppm range, was analysed by ESCA at normal and grazing emission angle to determine both depth distribution and bonding state of the different elements. The BN‐covered surface was obtained by cacuum annealing at 850 °C. The thin BN layer remains stable on the surface during all the oxidation and heat treatments and prevents oxidation of the substrate. Oxidation only develops at the few sulphur‐covered areas, in the same way as for a totally sulphurcovered surface. The different segregation phenomena are qualitatively explained within classical segregation models.
Analysis in in situ prepared surfaces of an iron oxide based dehydrogenation catalyst
Authors: Muhler M. , Schlögl R. , Ertl G.
Published: May 2005

An X‐ray photoelectron spectroscopic study is presented for an industrial catalyst surface, which is in its active form only accessible after reaction under technical conditions. A high pressure‐high temperature reactor was attached to a surface analysis system. It allowed rapid transfer of a sample between the reaction environment and the UHV required for surface analysis. The active phase was identified as a ternary iron potassium oxide. No evidence was found for the previously suggested presence of a binary potassium hydroxide or carbonate phase in solid or liquid form. A new model of the active catalyst is proposed.
Characterization of supported Pd catalysts
Authors: Papp H. , Kamp P.
Published: May 2005

Supported Pd catalysts are active for the oxidation of carbon monoxide at low temperature. To understand the catalytic action on a molecular basis, catalysts with different metal loadings have been investigated by activity tests with regard to CO2 formation, by CO chemisorption, N2 physisorption and XPS measurements. The rate of CO2 formation turns out to be independent of CO partial pressure and dependent on O2 partial pressure (0.3 order) in the pressure and temperature range investigated. The activation energy of CO oxidation has a value of 40 kJ mol−1 independent of metal loading. The specific surface are and the pore structure of the support is not significantly changed even by a metal loading as high as 17 weight per cent. The irreversibly adsorbed amount of CO—determined at 273 K in a vacuum microbalance—is linearly related to the CO2 formation rate. The dispersion determined by XPS measurements is proportional to that calculated from the CO chemisorption results.
RBS and AES depth profiles of Pd deposited on Si after annealing at different temperatures
Authors: Clement M. , Sanz J. M. , Climent A. , Martinez‐Duart J. M.
Published: May 2005

Palladium silicide films were obtained after annealing thermally evaporated Pd layers on <111> p‐type Si substrates. The silicide layers formed at different temperatures were characterized by Rutherford backscattering (RBS) and Auger electron spectroscopy (AES). A quantification of the AES depth profiles was made by comparing the profiles with the RBS results. The sputtering time scale was converted into a depth scale using the values of the sputtering yields calculated from the RBS thickness and the AES sputter times. The transformation of the measured Auger intensities into concentration allowed a quantitative study of preferential sputtering in Pd2Si, taking into account the composition given by RBS. Finally we estimated the depth resolution of the AES profiles by comparing the width of the interfaces obtained from both techniques.
Investigation of cross‐contamination during Si‐implantion in GaAs with SIMS
Authors: Meuris M. , Vandervorst W. , Maes H. E.
Published: May 2005

The contamination of Si‐implantation in GaAs was analysed with SIMS. This was done by measuring the molecules composed of the ‘contamination‐atoms’ and the matrix atoms. It was concluded that there exists a co‐implantation of 14N15, 10B19F, 11B18O up to 40% of the dose for the 29Si‐implantation in the worst case and 20% of 14N2 for the 28Si‐implantation. Electrical measurements and a residual gas analysis confirmed these results. A good mass separation for the implanter was found.
Combined surface analytical and electrochemical studies for corrosion research
Authors: Strehblow H.‐H.
Published: May 2005

The application of several surface analytical methods in addition to electrochemical studies for corrosion research is described. Passivity of metals is taken as an example to demonstrate the advantages and limits of different in situ and ex situ methods. After a short survey of the surface analytical tools a short introduction to the passivity of metals is given. The major part of this work describes specific systems and how surface analysis provides a deeper understanding for the corrosion mechanisms and the nature of the passive layers. Fe, Cr, Fe/Cr alloys, Cu and Cu/Al alloys are discussed as examples. This review demonstrates that a combined application of a variety of methods leads to a mutual confirmation of the data and to a reliable explanation by models. For comparative results for the different studies a careful and sometimes a very difficult specimen pretreatment is a necessary requirement and may help to overcome controversial points of view.
Sulphide formation on the surface of binary AgPd alloys studied by XPS, AES, SEM/EDX
Authors: Hautaniemi J. , Heinonen M. , Juhanoja J. , Suoninen E.
Published: May 2005

Formation of a sulphide layer on the surface of AgPd alloys has been studied by XPS, AES, SEM/EDX and optical microscopy. In accordance with earlier studies of sulphidization of AuAgCuPd alloys, no palladium‐enrichment can be observed in the sulphide layer formed on AgPd samples treated in Na2S solutions. Strong Pd‐enrichment is observed underneath the sulphide layer on the surface of the metal substrate. The enrichment takes place rather quickly and is associated with a palladium‐deficient layer underneath the substrate surface, suggesting diffusion of palladium to the surface of the metal phase.

In polycrystalline materials sulphidization also takes place along the grain boundaries. The sulphide phases on the grain boundaries seem to act as channels for the migration of the silver atoms to the sample surfaces. This process leads to further sulphidization of the whole sample surface and overlaps the direct sulphidization which eventually stops because of the formation of a palladium‐enriched layer. The grain boundary connected process is strongly influenced by the composition of the electrolyte in which the sample is immersed.
Characterization by XPS and AES of oxide films formed on stainless steel 304 under various PWR conditions
Authors: Couling S. B. , Welch L. S.
Published: May 2005

Incorporation of60Co during growth of oxide films on alloys in PWR primary coolant circuits give rise to a significant radiological hazard. These oxide films have a duplex structure consisting of a thin inner layer and an outer layer of crystallites. XPS and AES techniques have been used to examine the oxide layers produced under a variety of controlled PWR coolant conditions. The elemental ratios obtained by the various techniques can be correlated with the extent to which the surfaces are covered with crystallites. The surfaces of coupons with thick outer layers of crystals were depleted in chromium with respect to the base metal composition, while examination of a specimen from which the outer layer had been removed chemically showed a significant enrichment of chromium.

The relative differences between the oxides were analysed easily by these surface techniques. However, the absolute accuracy of the elemental composition was in some doubt owing to the lack of suitable, rigorously computed sensitivity factors for use in the quantitative analysis of spectra. An attempt has been made to refine the method for producing sensitivity factors appropriate to these materials.
SAM analysis of fracture surfaces of ceramics
Authors: Hamminger R.
Published: May 2005

The application of high resolution scanning Auger electron spectroscopy on non‐conductive ceramic materials has been demonstrated. Advanced ceramics, e.g. SiC, ZrO2, AIN and Si3N4, have been analysed at a low beam voltage and a low beam current of typically 3 kV and 20 nA. Ion conductive materials were analysed at elevated temperatures up to 550°C. The application on interfacial details of advanced ceramic materials was found to be restricted only in the case of very fine‐grained materials, due to the unsufficient lateral resolution when very weak primary conditions were used to reduce charging.
XPS characterization of ultrafine Si3N4 powders
Authors: Bertóti I. , Varsányi G. , Mink G. , Székely T. , Vaivads J. , Millers T. , Grabis J.
Published: May 2005

The mechanical properties of Si3N4 based ceramic bodies are largely controlled by the phases formed on the grain boundaries during sintering. For this reason determination of the state and the chemical composition of the surface of the starting Si3N4 powder is of prime theoretial and practical importance, especially in the cases when advanced ultrafine powders are used. In this work an ultrafine Si3N4 powder, obtained by high temperature plasma nitridation of silicon, has been characterized by XPS. Oxygen, carbon and also a small amount of potassium were detected as surface impurities. The Si 2p and Si (KLL) spectral lines could be decomposed into two components corresponding to silicon in Si3N4 and SiO2 phases. From angle‐resolved and Ar‐ion depth‐profiling experiments a layer model, consisting of a Si3N4 core covered by a relatively thick SiO2 layer and a carbon contaminant overlayer, could be elucidated.
Determination of the grain boundary diffusion coefficient of oxygen in Cr2O3
Authors: Sockel H. G. , Saal B. , Heilmaier M.
Published: May 2005

The penetration of tracers into polycrystals is described by the solution of the corresponding differential equation by Suzuoka.1 A direct determination of DGB δ (DGB: grain boundary diffusion coefficient, 2δ: grain boundary thickness) by this complex solution is not possible. Therefore, so far, an approximate solution for intermediate times t and large penetration depths y derived from the Suzuoka solution has been used to obtain DGB δ by a graphical method. For very small DGB the penetration profiles of stable isotopes in polycrystals can be measured by SIMS. Under these conditions the graphical method cannot be applied. For this reason, a new numerical method based on the exact solution of Suzuoka had to be developed. It is applied and verified in the determination of DGB for oxygen in Cr2O3.
ESCA Studies of MoO2 and MoO3
Authors: Brox B. , Olefjord I.
Published: May 2005

The metallic and the oxide states of Mo were analysed by ESCA. A pure Mo metal sample was ion‐etched and analysed. MoO3 was formed by oxidation of Mo in oxygen. The four‐valent MoO2 was prepared by oxidation of Mo in a H2O/H2 gas mixture and by reduction of MoO3 in hydrogen.

The binding energies of the Mo 3d5/2 and Mo 3d3/2 signals representing the metallic state are 227.9 and 231.0 eV, respectively. The chemical shift of the Mo 3d signals recorded for MoO3 is 4.8 eV.

Each of the Mo 3d spin–orbit components recorded from MoO2 consists of two peaks. The area ratio between the low and high intensity peaks are 1:2. The shift of the low intensity peak is 3.2 eV corresponding to the value expected by linear interpolation between the four and six valent states. The high intensity peak is positioned at 1.6 eV higher binding energy than the metallic state. It is suggested that the low energy shift is due to the structure of MoO2; the MoMo distance in the structure is either 2.5 or 3.1 Å. Interaction between metal atoms gives a partly filled σ‐bond which screens the core electron and thereby the shift becomes lower. The chemical shift of the Mo4+ signal recorded from molybdenum oxyhydroxide is 3.2 eV. It is the same as for the low intensity peak in MoO2 representing the ionic character of the Mo atoms in the oxide.
Implantation of 29Si into GaAs {100}: Surface analysis and modelling of the dopant distribution
Authors: Hill I. R. , Lau W. M. , North R. A.
Published: May 2005

SIMS concentration profiles have been measured for 29Si ions implanted into GaAs {100} in the energy range of 30 to 400 keV and at doses from 5 × 1012 to 5 × 1014 cm−2. It was found that these profiles could be fitted successfully to Pearson IV distributions enabling the establishment of projected range statistics for modelling purposes. The Si concentration profiles were found to be a function of not only implantation energy but also of the tilt and twist angles of the substrate wafer and of the implant dose. Raman spectroscopy was used to monitor the disorder induced in the GaAs substrate by the Si implantation. The SIMS profiles are discussed in terms of planar channelling of the Si ions and the Raman data are used in interpreting the dose dependence of the profiles.
Test of algorithm for background correction in XPS under variation of XPS peak energy
Authors: Tougaard S. , Braun W. , Holub‐Krappe E. , Saalfeld H.
Published: May 2005

The consistency of a recently proposed algorithm for background correction in XPS is studied, under variation of the XPS peak energy, by use of synchrotron radiation. Two approximations for the inelastic scattering properties of the solid are investigated. Both algorithms are found to account well for the variation in the inelastic scattering properties of the solid when the Au 4f XPS peak energy is varied. Small differences can be ascribed to the influence of surface excitations which are not included in the algorithm.
An XPS and SIMS analysis of biodegradable biomedical polyesters
Authors: Davies M. C. , Short R. D. , Khan M. A. , Watts J. F. , Brown A. , Eccles A. J. , Humphrey P. , Vickerman J. C. , Vert M.
Published: May 2005

The polymer surface compositions of some polyesters of importance in biomaterial science and advanced drug delivery have been examined by x‐ray photoelectron spectroscopy (XPS) and static secondary ion mass spectrometry (SSIMS). The XPS results show good quantitative stoichiometric correlation with the known chemical composition of the polyesters. The SIMS spectra show systematic fragmentation patterns in both positive and negative ion modes for the series of structurally related polymers. Evidence for the presence of radical cation formation in SIMS is presented. Comparison between the SIMS spectra of poly‐glycolic acid and poly‐lactic acid and the pyrolysis mass spectra of these polymers are made, and conclusions drawn on the different mechanisms of fragmentation. The combined application of SSIMS and XPS is shown to give a highly detailed analysis of these polyesters.
He(I) photoelectron studies of lidocaine films on liquid surfaces
Authors: Ballard R. E. , Jones Jimmy , Read Derek , Inchley Andrew , Cranmer Martin
Published: May 2005

The He(I) photoelectron spectra are reported of lidocaine (ω‐diethylamino‐2,6‐dimethylacetanilide) in the form of the free base, the hydrochloride, the ω‐N‐methyl halides and the ω‐N‐methyl hydrogen sulphate as surface films on liquid solutions.
Experiments on imaging X‐ray analytical methods
Authors: Gurker N. , Ebel M. F. , Ebel H. , Hedrich H. , Bavdaz M. , Giefing G.
Published: May 2005

X‐ray induced analysis of matter offers solutions to a great variety of analyst's questions in various disciplines. Based on the physical nature of primary interaction (photoelectric absorption, elastic/inelastic scattering) and on the secondary specimen response (modulated primary radiation, fluorescent radiation, photoelectrons, Auger electrons), a powerful family of different analytical techniques has evolved. This paper emphasizes the methods of x‐ray photoeletron spectrometry (XPS) and x‐ray fluorescence analysis (XRF), covering depth information ranging from ca. 1 nm (XPS) to > 10 μm (XRF). Scanning schemes to extract spatial resolution of the specific analytical signal are presented. These methods operate in (hardware‐based) line‐selection modes during data acquisition and are essentially based on computer‐(software‐)aided data decoding to achieve point information (element map). Operating principles, alternative concepts, experimental set ups, results and some future trends are summarized.
Redistribution of boron during thermal oxidation of silicon studied by SIMS using Ar+ bombardment and the MISR method. Part I: Methodology
Authors: Michiels F. , Butaye L. , Adams F.
Published: May 2005

Quantitative depth profiling of boron through SiO2/Si interfaces, when profiling with Ar+, is complicated by the matrix effects. The presence of oxygen affects the sensitivity of boron by three orders of magnitude and accurate determination of the distribution of the distribution coefficient of boron at the interface is only possible when the matrix effects can be elminated or taken into account in the quantification. By using matrix‐sensitive correlation factors, a sensitivity curve of boron at different primary ion current densitites was established. This relation shows a good long‐term reproducibility. Moreover, a physical interpretation of the shape of the sensitivity curve of boron is given by comparison with pure Si and SiO2. Tentative explanations for the behaviour of different SixOyz+ species in conditions of varying primary ion current density and oxygen backfill are given. The influence of the oxygen backfill pressure on the sputter rate of silicon was investigated and problems arising in the profilation of boron in SiO2/Si interfaces were addressed. Practical applications of the described methodology are discussed in Part II of this series.
Redistribution of boron during thermal oxidation of silicon studied by SIMS using Ar+ bombardment and the MISR method. Part II: Applications
Authors: Michiels F. , Butaye L. , Adams F.
Published: May 2005

Boron‐implanted silicon samples were oxidized (± 1100°C, 20–140 min) in an oxygen ambient to study the redistribution during thermal treatment. The use of matrix‐sensitive correlation factors, to account for the matrix effect when profiling boron through a SiO2/Si interface under Ar+ bombardment, was evaluated. A correction procedure based on the calibration curve of Part I of this series was applied for this purpose. The internal precision of the procedure as estimated from several tens of profiles is of the order of 25%. The accuracy was assessed by comparison of the quantified SIMS profiles with boron profiles determined with sputtered neutrals mass spectrometry (SNMS). SIMS data indicate an enrichment in the SiO2 phase of a factor of 2–3. SNMS data surpass the SIMS data by a factor of three and indicate a distribution coefficient of 9. The segregation coefficient is independent of the oxidation time. Samples with a high concentration of boron showed an anomalous diffusion behaviour, which can be attributed to the formation of boron precipitates which could be visualized by spatially resolved depth profiling with ion‐sensitive imaging.
An altered layer model for sputter‐profiling
Authors: Carter G. , Katardjiev I. V. , Nobes M. J.
Published: May 2005

An altered layer model is developed, consisting of an outer surface or sputtering layer from which atoms are ejected by ion bombardment and an adjacent deeper layer in which atomic constituents are spatially homogenised by bombardment‐induced mixing processes and between which layers atomic constituents are again intermixed. The model is applied to the case of sputtering erosion through an interface, and broadening effects are examined. It is shown that the model relaxes, on the one hand, to earlier treatments of non‐distinguishable sputtering and altered layers and, on the other hand, by assuming multiple altered layers, to earlier continuum (non‐discretized layer) models. Suggestions for controlled experimental studies for model verification are made.
Selective XPS technique for analysis of submicrometer metal line sidewalls on semiconductor devices
Authors: White Eric J.
Published: May 2005

The sidewalls of the metal connection lines used in semiconductor devices have different process histories from that of the top of the metal film. A new technique has been developed to analyze sidewall surfaces on product wafers using x‐ray photoelectron spectroscopy (XPS). This tecniques allows selective analysis of the sidewall region, providing specfic information on the chemical state of the sidewall, including residual contamination or etch by‐products remaining after line formation and the effects of further processing on this material.
Ion sputter rates of CrMnFe spinel oxides
Authors: Wild R. K.
Published: May 2005

The oxide which forms on stainless steel is duplex in nature, with an outer spinel covering an inner rhombohedral Cr2O3. The thickness of the oxide is only a few micrometers, even after many thousands of hours of oxidation at high temperatures, and hence surface analytical techniques are required to characterize the oxide. In particular, depth analysis is obtained using the scanning Auger microprobe in conjunction with argon ion bombardment. The etch rates are at present assumed to be the same as that measured using a tantalum oxide standard. To obtain a more accurate measure of sputter rates on the spinel oxides 20%Cr/25%Ni/TiN‐strengthened steel has been oxidized and the thickness determined by independent means. These data have then been used to determine the etch rates, which are compared with that on tantalum pentoxide.
Composition of TiN diffusion barriers in contact holes of advanced integrated circuits: A challenge for quantitative Auger spectroscopy
Authors: Pamler W. , Kohlhase A.
Published: May 2005

TiN is used in advanced integrated circuits as a diffusion barrier between Al metallization and Si substrate. Quantitative analysis of the TiN composition in contact holes of submicron devices is a particular challege for Auger spectroscopy owing to the contact hole geometry and topography (low signal‐to‐noise ratio, shadowing effects, scattering of primary electrons) and owing to material‐related problems (peak overlapping and lineshape changes, preferential sputtering, crystalline effects). It will be shown how methods of sample preparation and data evaluation can be used to advantage in solving these difficulties. The analysis reveals that the sputter‐deposited barrier layer is depleted in nitrogen at the contact hole wall.
Computer‐Aided quantification of AES and XPS spectra
Authors: Moir P. A. , Fitzgerald A. G. , Storey B. E.
Published: May 2005

The uses of a computer‐accessed database of elemental information relevant to quantitative interpretation of Auger electron and x‐ray photoelectron spectra will be described. Such a database has been compiled containing data on some 70 elements for access via UCSD Pascal computer programs implemented on IBM‐compatible microcomputers, Basic information required for the calculation of AES and XPS matrix factors is present in the database and routines for easy updating and extending of the information present are available. Programs for rapid calculation of the matrix factors needed for accurate quantification have also been developed to run in tandem with these library files. The simple data correction procedures present in these programs provide the analyst with a rapid method for obtaining an estimate of surface composition. Use of programs of this type help to prevent error by relying on the computer‐accessed library files for elemental information, help to prevent duplication of effort, and are of use in introducing the new surface analyst to the theoretical background to quantification. Some simple examples of uses of the programs are given.
Minimum detectable dimension, resolving power and quantification of scanning Auger microscopy at high lateral resolution
Authors: Cazaux J.
Published: May 2005

Using a two‐Gaussian model for the radial distribution of the emitted Auger electrons, it is shown that the resolving power (point‐to‐point resolution) is governed by the incident probe diameter d, while the minimum detectable dimension dm may be less than d. The convolution/deconvolution problem of Auger profiles is also considered with the transfer function of scanning Auger microscopy (SAM).

Auger profiles across various flat distributions (single stripe, i.e. single quantum well; isolated rectangular details; stripe arrays; i.e. superlattices; and linear concentrations at non‐abrupt interfaces) are estimated showing the distortion of the experimental profiles by the radial distribution of Auger electrons.

For small details, the apparent concentration looks very different from the true one and a two‐point analysis procedure is suggested for improving the quantification of SAM at high lateral resolution as an alternative to deconvolution of the Auger profiles.

The same analysis may be applied to other analytical microscopies particularly to electron probe microanalysis of a specimen having a surface compsition different from that of the bulk.
Surface composition analyses of Co–Ni alloys under Ar+ ion bombardment by AES and ISS: A possible standard sample for surface chemical analysis
Authors: Kurokawa A. , Shimizu R. , Kubota Y. , Kang H. J.
Published: May 2005

The change in surface composition of Co(50.4 at.%)–Ni alloy under Ar+ ion bombardment was investigated by Auger electron spectroscopy (AES) and ion scattering spectroscopy (ISS). The surface concentrations were estimated by employing a spectrum synthesis method, since the Co and Ni signals in both AES and ISS spectra overlap each other. The results based on the quantifications by AES and ISS have indicated that the composition of the Co–Ni alloy surface under Ar+ ion bombardment is the same as the bulk composition within the accuracy in quantification, leading to the conclusion that ion bombardment does not cause surface composition change in the Co–Ni alloy. This supports the proposal that the Co–Ni alloy system is an appropriate reference material for surface chemical analysis.
Quantitative Auger electron spectroscopy of binary systems. Matrix correction
Authors: Zagorenko A. I. , Zaporozchenko V. I.
Published: May 2005

The matrix correction factor, M, has been determined for 1953 binary systems. The calculated M values are in the range 0.3–2.6. The probable error, with no account being taken of the matrix effect, is 30%. A study has been made of the effect on M of different methods of calculation, the experimental conditions of the analysis, the choice of the Auger lines and the concentration of the system analysed. The greatest effect on M values is the choice of equations used for calculating the escape depth of the Auger electrons. Measurements of concentrations were carried out on scribed samples of cobalt, vanadium, iron and copper silicides, and lead telluride. On the basis of a comparison of the known bulk concentrations and the calculated values, an expression has been chosen for calculating the escape depth of the Auger electrons that gives the best results.
Angular resolved sputtering yields of noble metals and an Au–Ag alloy
Authors: Huang W.
Published: May 2005

Sputtering of noble metals and an Au–Ag alloy with low keV ion bombardment is investigated by means of measuring angular distribution of sputter‐deposited material and by analysing the bombarded target with low energy. Auger electron spectroscopy (LEAES). The measurement provides information on the angular‐resolved sputtering yields and the compositional variation of the bombarded surface. The angular distributions of the sputtered particles vary with the measurement conditions: the energy and the type of bombarding ions, the crystallity of the bombarded surface and the vacuum conditions during sputtering. The measurement gives evidence of ion bombardment induced surface segregation on sputtering of the Au–Ag alloy.
Effect of temperature on chromium segregation to CoO(100) and NiO(100) surfaces
Authors: Hirschwald W. , Sikora I. , Stolze F. , Oblakowski J.
Published: May 2005

Surface concentrations of chromium in CoOCr2O3 and NiOCr2O3 single crystals in dependence on bulk concentration and annealing temperature were determined by means of SIMS and XPS. From the temperature dependence, the heat of segregation ΔHs was calculated. Its value changed with bulk Cr concentration in the CoOCr2O3 system, whereas for the NiOCr2O3 system ΔHs was found to be constant in the whole range of bulk concentrations and temperatures studied.
On the theory of quantitative in‐depth composition information in X‐ray photoelectron spectroscopy
Authors: Tofterup Arne L.
Published: May 2005

The x‐ray photolectron spectroscopy (XPS) peak shape has previously been described by a single parameter D, which is the ratio of the peak area to the increase in background signal 30 eV below the peak energy. The aim was to extract in‐depth composition information from spectra. The influnce of elastic scattering on that background signal has been investigated for homogeneous and inhomogeneous transition and noble metals. Accurate, analytic expressions for D were derived, based upon a second‐order calculation of the inelastic scattering events and a so‐called P1 approximation of the elastic scattering. The background signal, and therefore D appears to depend strongly on elastic scattering in pronounced inhomogeneous solids but only weakly in the more homogeneous solids.
Surface analysis by sputtered neutral mass spectrometry with electron‐beam‐excited plasma
Authors: Hashiguchi Y. , Hayashi S. , Ohtsubo T. , Kato S. , Hamagaki H. , Hara T. , Aoyagi K. , Namba S.
Published: May 2005

A new type of sputtered neutral mass spectrometer, named SNART (Sputtered Neutral Analysis—Riken Type), was evaluated. SNART uses an argon plasma that is driven by an electron beam. The plasma is used for both sputtering of the sample and post‐ionizing the sputtered neutral atoms. A depth profile of multilayered Ge/Si was taken by SNART to evaluate depth resolution. The quantitativeness of SNART was also checked using a stainless‐steel sample. The results were compared with those by conventional SIMS and glow discharge optical emission spectrometry. The following features of SNART were confirmed: (1) high post‐ionization efficiency; (2) high depth resolution; (3) high sputtering rate; (4) no matrix effect on post‐ionization efficiency; and (5) high quantitativeness.
High spectral and angular resolution studies of sputtered zirconium atoms
Authors: Cullin D. Wm. , Moryl J. E. , Jones P. L.
Published: May 2005

We present the first results from a new apparatus for high spectral and angular resolution studies of sputtered neutral species. The sputtering experiments employ laser‐induced fluorescence and a compact fiber‐optic‐based detection system to yield state‐specific angular distributions for the sputtered atom flux. The angular resolution is of the order of 3° and a 260 MHz residual Doppler shift is estimated for the observed atomic transitions. The angular distribution for ground‐state zirconium atoms shows clear deviations from the cosine dependence expected from linear cascade theory when sputtered by 1.5 keV Ar+ ions incident at 60° from the surface normal. The peaking of the distribution in the forward direction suggests that a significant fraction of the atoms is ejected by a direct mechanism.
Radiation‐induced sample modification in surface analysis: InP as an extreme example
Authors: Gries W. H.
Published: May 2005

Spectacular topographical effects on InP resulting from ion and electron irradiation, both separately and simultaneously, at conditions common for surface analysis, are used as an example of drastic sample modification. Previously published observations (which include ion irradiation‐induced on‐surface growth of crystalline ‘stubs’ of InP as well as a strong synergetic response to simultaneous irradiation by ions and electrons) are summarized and the ‘microregion’ model proposed for interpretation of the ion‐induced effects is updated and underpinned by additional evidence. This model suggests that mass transport is initiated and proceeds in subsurface regions rather than on the surface (as has been proposed for impurity‐seeded cone growth). Possible explanations are put forward for the synergetic effect of simultaneous ion and electron irradiation. Various cases of synergetic binary interaction are pointed out.
Quantitative trace analysis of technical materials with solid state mass spectrometry: An analytical strategy for SIMS
Authors: Grasserbauer M. , Stingeder G. , Friedbacher G. , Virag A.
Published: May 2005

Based on an evaluation of important solid state mass spectrometric techniques regarding detection power, potential for quantitative analysis and applicability, an analytical strategy for the quantitative analysis of technical materials with high‐performance SIMS that has the broadest applicability of all solid state mass spectrometry techniques is discussed. The major topics dealt with are reduction of random and systematic errors, preparation and characterization of suitable reference materials and assessment of precision and accuracy. It is intended to demonstrate that extensive procedures have to be applied to obtain accurate quantitative results—not only for SIMS but also for the other solid state mass spectrometric techniques.
Electrochemical and second harmonic generation investigation of nickel corrosion in 0.1 M NaOH
Authors: Biwer B. M. , Pellin M. J. , Schauer M. W. , Gruen D. M.
Published: May 2005

The study of metallic corrosion has been hampered in the past by the lack of reliable in situ surface‐sensitive techniques. The application of second harmonic generation (SHG) to the investigation of such problems was demonstrated in earlier work on Fe corrosion. The present study further illustrates the general utility of SHG as a surface probe by extending its use in conjunction with standard electrochemical methods to the study of the Ni electrode in 0.1 M NaOH. The initial Ni oxidation product is shown to be different from that comprising the passive film, which in turn is shown to change over the region in which the electrode exhibits passive behavior. The use of two different laser frequencies for the production of SHG helps one to discriminate between charging and compositional effects in the interpretation of changes in the SHG signal.
Electron‐stimulated desorption of neutrals from 6063 aluminum—velocity distributions detected by 193 nm non‐resonant laser ionization
Authors: Young C. E. , Whitten J. E. , Pellin M. J. , Gruen D. M. , Benbow R. L. , Jones P. L.
Published: May 2005

Electron‐stimulated desorption of neutrals from methanol‐dosed 6063 aluminum alloy has been monitored by laser ionization at 193 nm wavelength. Primary electron energies were in the range 1–3 keV. Time‐of‐flight spectra for the neutral desorbate were characterized by a low value of the peak velocity (250 m s−1) and a non‐Boltzmann form of the distribution. Neutral desorption was ascribed to the parent methoxy (CH3O) species, based on mass spectrometry of the laser‐ionization fragmentation pattern as a function of intensity. Ionic desorption was dominated by H+, which was observed to have kinetic energy peaked at ∼3 eV. Approximate estimates of neutral and ion yields were made, based on ion‐optical modeling of apparatus transmission characteristics.
A chemical and morphological study of phosphorylated chrysotile fibres, using FTIR, EPXMA and AAS
Authors: Berghmans P. A. , De Waele J. K. , Philippaerts J. G. , Vasant E. F. , Adams F. C.
Published: May 2005

Changes in the surface composition of different chrysotile and chrysophosphate fibres upon leaching in oxalic acid and bidistilled water measured with Fourier transform infrared spectroscopy (FTIR) and electron probe x‐ray microanalysis (EPXMA) are presented. The results are supplemented with data obtained by atomic absorption spectroscopy (AAS) and colorimetry for the measurement of the leached magnesium, iron, phosphorus and chloride in solution. This assists in the elucidation of the potential consequences of fibre surface properties in relation to the carcinogenic potency and biological activity. This study demonstrates the potential of the FTIR and EPXMA techniques for the characterization of natural and physicochemically modified and depleted fibres.
Conversion of Auger sensitivities at one primary excitation energy to those at another
Authors: Sato T. , Nagasawa Y. , Sekine T. , Sakai Y. , Buonaquisti A. D.
Published: May 2005

In Auger electron spectroscopy, the relative sensitivities of elements, which are widely used in quantitative analysis, are primarily obtained by measurement. Nevertheless, it is very tedious to collect all relative elemental sensitivity factors for different primary electron beam energies. In view of this, we have examined methods of deriving the relative sensitivity factor for an arbitrary electron beam energy from one experimental value determined at a set energy. For this calculation, we have to consider the contributions of the ionization cross‐section and the electron backscattering factor. Several formulas for the ionization cross‐section and the backscattering correction factor have been reported. We have performed experiments to examine their correction accuracy. It was found that when Gryziński's formula is used as the ionization cross‐section and Love‐Scott's formula as the backscattering correction factor, the difference between calculated sensitivity values and measured values was found to be <15% for excitation energies of <20 keV.
The characterization of wafer surfaces and interfaces using high‐frequency phonons
Authors: Rani Hamid Bin , Edwards S. C. , Wigmore J. K. , Collins R. A.
Published: May 2005

We show that the scattering of nanosecond heat pulses can be used to characterize the surface quality of single crystal wafers for device applications. The technique is sensitive because the high‐frequency phonons that make up the heat pulses have wavelengths that are comparable with the typical scale of surface imperfection. The advantages of the technique are that it is non‐destructive, can be applied to both semiconductors and insulators, requires minimal preparation and can be used to observe deep subsurface structure.
AES study of palladium overlayers on polycrystalline copper
Authors: Heras J. M. , Viscido L. , Wedler G. , Borgmann D.
Published: May 2005

The growth of Pd layers on polycrystalline Cu substrate at 176 K and 300 K was studied in an Auger system with facilities for photoelectric work function (WF) measurements and automated data acquisition. The LVV and MVV Auger transitions of Cu, as well as the corresponding MVV and NVV of Pd, were monitored in relation to Pd overlayer thickness, annealing temperature and sputtering time. The ‘local’ WF change, determined through the secondaries' cut‐off shift, and the absolute photoelectric WF were also monitored.

The initially linear increase in the Pd atom fraction, with only one break during deposition at 300 K, suggests a Stranski–Krastanov film growth mechanism. The simultaneously monitored Auger M23M45M45 Cu doublet at 59–61 eV changes from the very beginning of the Pd deposition into one broadened peak at 61 eV, possibly owing to a roughness effect. With sputtering, the slope of the Pd concentration at the interface decreases when the temperature of deposition and sputtering increases from 176 K to 300 K, indicating diffusion of Pd even at 300 K. By sputtering with Ar+ ions of 5 keV, a depth resolution of ∼3.2 nm was found. Annealing at T > 473 K causes a rapid diffusion of Pd atoms into the Cu substrate.

The ‘local’ WF is affected dramatically by Pd deposition and sputtering, while the average photoelectric WF is not as sensitive.
A microbeam analytical study of a‐C: H films
Authors: Fitzgerald A. G. , Henderson A. E. , Storey B. E.
Published: May 2005

Carbon films prepared by sputtering, ion beam deposition methods and chemical and physical vapour deposition methods have been studied by a range of microbeam analytical techniques. The presence of hydrogen and hydrocarbon components in these films has been established regardless of whether hydrocarbon gas is used in the deposition process. The α‐carbyne and diamond modifications of carbon have been identified in some of these films. The sensitivity of these carbon films to electron and ion irradiation is discussed. The form of carbon bonding has been investigated by x‐ray photoelectron spectroscopy.
Comparative study of TiNx films deposited by reactive ion beam sputtering at 77 and 300 K
Authors: Buschert R. C. , Gibson P. N. , Gissler W. , Haupt J. , Manara A. , Jiang X. , Reichelt K.
Published: May 2005

Comparative studies were performed on the chemical composition, the microstructure, residual stress, hardness and Young's modulus of titanium nitride films, which were prepared by reactive ion beam sputtering at substrate temperatures of 77 and 300 K. The main experimental parameter of sample preparation was the N2/Ar gas flow ratio r, which determines not only the chemical composition of the film, [N]/[Ti], but also its mechanical and electrical properties. The chemical composition was investigated by AES, XPS and RBS. Microstructural data were obtained by grazing incidence x‐ray diffractometry. The measurements indicate a mixed phase of Ti, Ti2N and TiN at lower r ratios and of cubic TiN at r > 0.05. From the integrated breadth of the diffraction lines, grain size D and strain ε were determined: 150–250 Å for D and 0.5–1.5% for ε The residual stress was measured by determining the bending of the substrate. Extraordinarily high compressive stress with pronounced maxima around stoichiometric composition was observed. The microhardness Hv and Young's modulus E were derived from the indentation loading–unloading curve, as measured with a nanoindenter. Values up to 25 GPa for Hv and up to 10 GPa for E were obtained.
Temperature dependence of the phosphorus segregation at the twin boundary in an Fe–4 at.% Si alloy
Authors: Lejček P. , Hofmann S.
Published: May 2005

AES of in situ fractured bicrystals of an Fe–4 at.% Si alloy containing traces of phosphorus was used to study the temperature dependence of the segregation at the symmetrical {112} (coherent twin) grain boundary between 773 and 1173 K. The observed enrichment of P decreases with temperature, whereas that of Si increases slightly. This behaviour is described by a mutual repulsive interaction coefficient α′ = 92 kJ mol−1 of P and Si and the corre‐sponding pure binary segregation enthalpies ΔH0P = −7.9 kJ mol−1 and ΔH0Si = −3.0 kJ mol−1, the absolute values of which are considerably lower than those reported for polycrystalline samples of FeP and FeSi. The differences are explained on the basis of orientation, concentration and interaction effects.
The effect of hydrogen content on silicon coordination in silicon oxynitrides: An Auger parameter study
Authors: Rivière J. C. , Crossley J. A. A.
Published: May 2005

Silicon oxynitride films prepared by plasma‐enhanced chemical vapour deposition (PECVD), with compositions in the range O/N = 0 to O/N = 0.89, and containing amounts of hydrogen in the range H(H + O + N) = 0.07–0.31, have been studied by measurement of the Auger parameter α = EK(Si KLL) – EK(Si 2s). A pure thermal oxide was also included. Depth profiles using 4 keV argon ions showed that the films were uniform in both composition and silicon coordination. Peak widths of the 2p, 2s and KLL features were measured as a function of oxygen fraction O/(H + O + N); in contrast to the films prepared by low‐pressure chemical vapour deposition (LPCVD) studied by Rivière et al., the widths of the 2p and 2s peaks were constant. However, the width of the KLL Auger peak went through a maximum near O/(H + O + N) = 0.5, as observed previously. The 2p and 2s width invariance is interpreted as being due to the presence of hydrogen, in that the weak hydrogen bonding allows strain due to varying bond angles and distances to be taken up more easily than in SiO and SiN bonds. The KLL variation, on the other hand, is suggested as arising from the effect of the core hole in the L shell, causing instantaneous local strain around the ionized Si atom associated with SiO and SiN bonds.

The dependence of the Auger parameter on the oxygen fraction O/(H + O + N) was different from that found for the LPCVD films in that it was accurately linear. As a result, the PECVD films do not obey the random bonding model of progressive substitution of N by O, but consist of a mixture of two phases, in agreement with Claassen and Kuiper who suggested the phases SiO2 and Six Ny Hz. The linear decrease in the Auger parameter is thus due to the proportionate decrease in the Six Ny Hz content. Plots of the Auger parameter as a function of (n2 − 1)/n2 were again linear, confirming the direct relationship between the parameter and the polarization energy found previously.
VAMAS surface chemical analysis technical working party—an overview of project objectives, progress and the requirements for further work
Authors: Seah M. P.
Published: May 2005

An update for 1989 is given for the VAMAS Surface Chemical Analysis Technical Working Party. The overall programme now has 26 projects targeted to solve key problems in the enabling base of AES, XPS, SIMS, SNMS and sputter depth profiling. Increased coordination of projects is leading to stronger project databases. Eleven of the projects have involved round robins, and details are provided of results where the analysis is complete and of project leaders where new participants are invited.
A comparison of the composition of thin films on substrates determined by EDX and surface analysis
Authors: Fitzgerald A. G. , Gillies A. D. , Watton H. L. L.
Published: May 2005

Single‐scattering Monte Carlo electron trajectory simulation has been implemented for the calculation of characteristic x‐ray production in thin films on substrates. The validity of the simulation has been verified by comparison with EDX results from various thicknesses of gold and silver films on silicon substrates over a range of electron energies. The simulation has been applied to binary thin films on substrates, and computational methods have been devised to eliminate the lengthy graphical techniques for film thickness and composition determination used previously. A comparison of calculated film compositions has been made with composition obtained by surface analytical techniques.
Determination of the centroid depths of the depth profiles of ion‐implanted analytes by angle‐resolved electron microbeam analysis
Authors: Gries W. H. , Koschig W.
Published: May 2005

Angle‐resolved signal ratio electron microbeam analysis (AR/SR/EMA) was applied for the determination of the centroid depth of the ion‐implanted depth profile of 100 keV 1016 cm−2 P in Si. The experiment is part of an investigation on the suitability of AR/SR/EMA for application in the (non‐destructive) calibration of ion‐implanted reference materials.