Determination of the intensity–energy response function of the ISA Riber MAC 2 electron analyser

Repoux, Monique; Darque-Ceretti, Évelyne; Casamassima, M.; Contour, J. P.

doi:10.1002/sia.740160141

Cited by 18 publications

(3 citation statements)

References 8 publications

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“…This is an iterative calculation, which begins with a horizontal background from point B. Shirley's method is traditionally used but does not represent the accurate energy-loss spectrum responsible for the peak background to be subtracted: it is assumed first that the probability for one electron of energy E to lose an energy T does not depend on E or on T, and secondly that the intensity is zero in an arbitrarily chosen point A. (4) The fourth method used has been developed by Tougaard.' The primary excitation spectrum F(E) is evaluated from the measured flux of emitted electrons j ( E )…”

Section: 2e+6mentioning

confidence: 99%

Comparison of background removal methods for XPS

Repoux¹

1992

Surface & Interface Analysis

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116

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Photoelectron peak areas are measured using various background removal methods. Linear, horizontal, Shirley's and Tougaard's backgrounds have been tested on many spectra for different pass energies in the spectrometer. These four values, obtained for each photoelectron line, are compared together and it is shown that the first three methods give proportional results. These values are then compared to theoretical intensities for five elements (Au, Ag, Cu, Ni, Cr) and one oxide (A1203). These theoretical calculations are based on the knowledge of the spectrometer transmission, photoionization cross-sections and inelastic mean free path, the product of which is commonly called the relative sensitivity factor. The best agreement is obtained when Tougaard's background is removed. INTRODUCTIONQuantitative surface analysis by XPS requires photoelectron intensities measurements. These intensities are usually connected to peak areas on n(E) spectra and these values are then used, with relative sensitivity factors, to calculate surface concentrations in routine spectral analysis.Before peak area measurement, the inelastic background should be removed. Therefore, the value obtained for intensity will depend upon the method used for this removal. Since several background subtraction processes exist, several values are available for one peak area so that the quantification with relative sensitivity factors that are published in the literature will not be reliable. Actually, relative sensitivity factors are either determined experimentally or calculated with photoionization cross-sections, inelastic mean free path and the spectrometer transmission function. In the former case, the exact method used for background removal is rarely known; in the latter case, it is necessary to know how to measure the accurate area in relation with this theoretical intensity. This explains why a recent quantitative XPS analysis round robin on Au-Cu alloys' has shown that the use of relative sensitivity factors is not a reliable method for quantitative surface analysis. EXPERIMENTALFive metals of high purity are used for this study: Au, Ag, Cu, Ni and Cr. Before measurements, the surface (1 an2) is cleaned with Ar ions at an energy of 4 keV, until carbon and oxygen peaks are less than -1% of the main peak. Spectra are then acquired with A1 Ka radiation without a monochromator. To avoid problems relating to the absolute intensities from one sample to another, Au 4f is systematically acquired between each spectrum.Besides these five elements, we have tested the stoichiometry determination by XPS on an a-alumina (001) 0142-242

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Section: 2e+6mentioning

confidence: 99%

Comparison of background removal methods for XPS

Repoux¹

1992

Surface & Interface Analysis

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116

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“…Comparing Eqn (13) with Eqn (1) and assuming no contamination of the surface and I cc E:. ', the only parameter missing in Eqn (13) is the transmission function T. If we introduce in Eqn (13) the above-determined T functions, the respective O/C ratios can be recalculated (Fig.…”

Section: Comparison Of Corrections Using the T Functions Determined Amentioning

confidence: 99%

Quantitative XPS. Part I: Experimental determination of the relative analyser transmission function of two different spectrometers — a critical assessment of various methods, parameters involved and errors introduced

Weng

Vereecke

Genet

et al. 1993

Surface & Interface Analysis

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The relative analyser trailsmission functions of two different XPS spectrometers (VG ESCA-3 Mk I1 and SSI X-F'robe of Fisons) have been determined experimentally by several methods presented in the literature. The transmission function of the VG ESCA-3 Mk I1 can be expressed as T cc En(E,/Ek)", where n is close to 0.8. The transmission function T of the SSI X-Probe cannot be presented as a separate function of En and Ek and it is expressed asThe possible influence of the efficiency D of the detector on the determined transmission functions is discussed. The advantages and disadvantages of the methods used are pointed out, together with their limitations and potential applications. The results show that some methods can only be applied to spectrometers such as the VG ESCA-3Mk I1 in which n is a constant or depends only on Ek . The method proposed by Hemminger et uf. [Surf. InterfaceAnal. 15, 323 (19%)) has been shown to be applicable to both spectrometers but a systematic error can be introduced when D is not constant. Such a systematic error can he reduced by another method but this method can only be applied to spectrometers in which the transmission function is known for a given analyser energy. t

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“…is the spectrometer transmission function [11]. 0 I is a constant factor, which depends on the x-ray radiation intensity.…”

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confidence: 99%

Beryllium nitride thin film grown by reactive laser ablation

et al. 2002

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Beryllium nitride thin films were grown on silicon substrates by laser ablating a beryllium foil in molecular nitrogen ambient. The composition and chemical state were determined with Auger (AES), X-Ray photoelectron (XPS) and energy loss (EELS) spectroscopies. A low absorption coefficient in the visible region, and an optical bandgap of 3.8 eV, determined by reflectance ellipsometry, were obtained for films grown at nitrogen pressures higher than 25 mTorr. The results show that the reaction of beryllium with nitrogen is very effective using this preparation method, producing high quality films.keywords: Beryllium nitride, laser ablation, thin films, wide bandgap, optical properties.

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Determination of the intensity–energy response function of the ISA Riber MAC 2 electron analyser

Cited by 18 publications

References 8 publications

Comparison of background removal methods for XPS

Comparison of background removal methods for XPS

Quantitative XPS. Part I: Experimental determination of the relative analyser transmission function of two different spectrometers — a critical assessment of various methods, parameters involved and errors introduced

Beryllium nitride thin film grown by reactive laser ablation

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