TY - JOUR A1 - Unger, Wolfgang A1 - Gross, Thomas A1 - Böse, Olaf A1 - Lippitz, Andreas A1 - Fritz, Thomas A1 - Gelius, U. T1 - VAMAS TWA2 Project A2: evaluation of static charge stabilization and determination methods in XPS on non-conducting samples. Report on an inter-laboratory comparison N2 - First results of an inter-laboratory comparison (27 participants in Europe, Japan and USA) of XPS data obtained with non-conducting samples are presented. Binding energies of Al 2s for alumina, N 1s and imide C 1s for Kapton and Sr 3p3/2 for a strontium titanate film on glass were obtained after static charge referencing with the help of 15 nm gold particles deposited at the surface of the test samples. For the alumina sample C 1s static charge referenced data are also presented. Repeat standard deviations (sr), between standard deviations (sb), reproducibility standard deviations (sR) and total means are evaluated from the experimental data. It can be stated that although the repeat standard deviation is as small as 0.05 eV in the best case, the standard deviation characterizing the reproducibility of the method is obviously not better than 0.15 eV in the best case at the present time. The knowledge of these standard deviations is important for metrology, validations of analytical procedures relying on qualitative photoelectron spectroscopy and XPS databanking. KW - XPS KW - ESCA KW - Binding energy KW - Inter-laboratory comparison PY - 2000 DO - https://doi.org/10.1002/1096-9918(200008)29:8<535::AID-SIA900>3.0.CO;2-5 SN - 0142-2421 SN - 1096-9918 VL - 29 SP - 535 EP - 543 PB - Wiley CY - Chichester AN - OPUS4-6939 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lippitz, Andreas A1 - Hübert, Thomas T1 - XPS investigations of chromium nitride thin films N2 - Cr–N film coatings were prepared by magnetron sputter deposition at different nitrogen partial pressures. The film characterisation by XRD and DTG gives average bulk compositions of Cr2N and CrN for the coatings. Highly sensitive XPS investigations were performed and the chemical and phase compositions of a film surface range of about 10 nm thickness was estimated quantitatively from the deconvoluted peak intensities. It is demonstrated that the composition of the surface of chromium nitride thin films differs from the core and is more complex in constitution. Not only chromium nitrides (Cr2N and CrN) but also chromium oxynitrides and chromium oxides (CrOx and CrOxHy) were detected. Metallic chromium was also found in films prepared at higher nitrogen flow. The concentration of the estimated phases shows dependence on film preparation and additional heat treatment. KW - XPS KW - ESCA KW - Physical vapour deposition (PVD) KW - CrN thin films PY - 2005 DO - https://doi.org/10.1016/j.surfcoat.2005.02.091 SN - 0257-8972 VL - 200 IS - 1-4 SP - 250 EP - 253 PB - Elsevier Science CY - Lausanne AN - OPUS4-10865 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Unger, Wolfgang A1 - Oran, Umut A1 - Swaraj, Sufal A1 - Lippitz, Andreas ED - Chandra, T. T1 - Ageing studies of plasma deposited organic films by surface chemical analysis (ESCA, ToF-SIMS, XAS) T2 - 5th International Conference on Processing & Manufacturing of Advanced Materials CY - Vancouver, Canada DA - 2006-07-04 KW - Plasma polymerized organic films KW - Ageing phenomena KW - ESCA KW - TOF-SIMS KW - XAS PY - 2007 SN - 0-87849-428-6 SN - 0255-5476 N1 - Serientitel: Materials science forum – Series title: Materials science forum VL - 539-543 IS - 539/543 SP - 623 EP - 628 PB - Trans Tech Publ. CY - Stafa-Zürich AN - OPUS4-14446 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Swaraj, Sufal A1 - Oran, Umut A1 - Lippitz, Andreas A1 - Unger, Wolfgang T1 - Surface Chemical Analysis of Plasma-Deposited Copolymer Films Prepared from Feed Gas Mixtures of Ethylene or Styrene with Allylamine N2 - Plasma deposited ethylene/allylamine and styrene/allylamine copolymer films were prepared and analyzed using XPS, NEXAFS and ToF-SIMS. The relative partial flow rate of the each monomer was used as the variable deposition parameter, while the other deposition parameters were kept constant at optimized values for the retention of functional groups. The effect of the variation in the relative partial flow rates of co-monomers on various chemical aspects of the films like unsaturation, nitrogen retention and branching was investigated revealing several non-linear correlations. This observation is taken as an indication for chemical copolymerization processes during film deposition. An attempt is made to compare these non-linear correlations with approaches which have been developed for classic radical copolymerization processes. The aging behavior of these plasma copolymer films was also studied; the results indicated a stabilization against oxidation in comparison to the aging of allylamine plasma homopolymers. KW - Ethylene-allylamine copolymer KW - ESCA KW - NEXAFS KW - Plasma polymerization KW - Styrene-allylamine copolymer KW - Surface characterization KW - TOF-SIMS KW - XPS PY - 2008 DO - https://doi.org/10.1002/ppap.200700106 SN - 1612-8850 SN - 1612-8869 VL - 5 IS - 1 SP - 92 EP - 104 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-16466 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Unger, Wolfgang A1 - Gross, Thomas A1 - Lippitz, Andreas A1 - Güttler, B. T1 - Uncertainty in measurement of overlayer thickness of thermally oxidized silicon using x-ray photoelectron spectroscopy N2 - Overlayers of SiO2 (nominally 4, 6 and 8 nm thick) on silicon, prepared by thermal oxidation, were investigated using x-ray photoelectron spectroscopy (XPS). The thickness of these overlayers was obtained from a measurement of the photoelectron intensities originating from the substrate and the oxide overlayer by applying an appropriate quantitative model. The uncertainty budget of that thickness measurement method is given. The relative combined standard uncertainty of the method was found to be 15%. The effective attenuation lengths or the corresponding electron inelastic mean free paths are of considerable importance for both the estimated values of overlayer thickness and combined standard uncertainties. The XPS results were compared with ellipsometry data. KW - XPS KW - ESCA KW - Uncertainty KW - Overlayer KW - SiO2 PY - 2000 DO - https://doi.org/10.1002/1096-9918(200012)29:12<891::AID-SIA943>3.0.CO;2-A SN - 0142-2421 SN - 1096-9918 IS - 29 SP - 891 EP - 894 PB - Wiley CY - Chichester AN - OPUS4-1075 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -