TY - JOUR A1 - Kormunda, M. A1 - Fischer, Daniel A1 - Hertwig, Andreas A1 - Beck, Uwe A1 - Sebik, M. A1 - Esser, N. T1 - Preparation of pulsed DC magnetron deposited Fe-doped SnO2 coatings N2 - Iron-doped SnO2 coatings were deposited in a 50 kHz DC-pulsed magnetron sputtering discharge. The pulses had a duration of 4 µs in selected gas mixtures from pure argon up to 60% of oxygen at a constant total pressure of 0.2 Pa. A single target of SnO2 with Fe inset was used. The mass spectrometry study detected the gas-related ions Ar+, O2+ and O+, where the last one becomes the dominant positive ion at higher oxygen contents. Atomic oxygen ions had a higher energy as it resulted from the collision-caused dissociation on the target surface. The tin-related species were detected as Sn+ and SnO+. SnO2+ species were not detected. The deposition rate decreased by using gas mixtures with oxygen as well as the corresponding amount of Sn-related species in the plasma. The increase of oxygen also increased significantly the sheet resistance of the films. The XPS study showed that the iron concentration decreased by using additional oxygen. But the O/Sn ratio in the coatings was constant, contrary to the increased FeO/Fe ratio in the films. An additional analysis of the coatings by spectroscopic ellipsometry has shown a dependence of the polarizability and the permittivity on the amount of oxygen used during the deposition. In contrast, the study has found no such dependence for the absorption of the layers. KW - Coatings KW - Magnetron sputtering KW - Optical properties KW - Sheet resistivity KW - SnO2 PY - 2016 UR - http://onlinelibrary.wiley.com/doi/10.1002/pssa.201532882/full DO - https://doi.org/10.1002/pssa.201532882 SN - 0031-8965 SN - 1862-6300 VL - 213 IS - 9 SP - 2303 EP - 2309 PB - WILEY-VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-38106 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kormunda, M. A1 - Fischer, Daniel A1 - Hertwig, Andreas A1 - Beck, Uwe A1 - Sebik, M. A1 - Pavlik, J. A1 - Esser, N. T1 - Deposition and characterization of single magnetron deposited Fe:SnOx coatings N2 - Coatings deposited by magnetron co-sputtering from a single RF magnetron with a ceramic SnO2 target with iron inset in argon plasma were studied. The mass spectra of the process identified Sn+ and SnO+ species as the dominant species sputtered from the target, but no SnO2+ species were detected. The dominant positive ions in argon plasma are Ar+ species. The only detected negative ions were O-. Sputtered neutral tin related species were not detected. Iron related species were also not detected because their concentration is below the detection limit. The concentration of iron dopant in the tin oxide coatings was controlled by the RF bias applied on the substrate holder while the discharge pressure also has some influence. The iron concentration was in the range from 0.9 at.% up to 19 at.% increasing with the substrate bias while the sheet resistivity decreases. The stoichiometry ratio of O/(Sn + Fe) in the coatings increased from 1.7 up to 2 in dependence on the substrate bias from floating bias (- 5 V) up to - 120 V of RF self-bias, respectively. The tin in the coatings was mainly bonded in Sn4 + state and iron was mainly in Fe2 + state when other tin bonding states were detected only in a small amounts. Iron bonding states in contrary to elemental compositions of the coatings were not influenced by the RF bias applied on the substrate. The coatings showed high transparency in the visible spectral range. However, an increased metallic behavior could be detected by using a higher RF bias for the deposition. The X-ray diffraction patterns and electron microscopy pictures made on the coatings confirmed the presence of an amorphous phase. KW - Metal oxides KW - Transparent conductive oxides (TCO) KW - Magnetron KW - Optical properties KW - Ellipsometry KW - XPS characterzation PY - 2015 DO - https://doi.org/10.1016/j.tsf.2015.11.009 SN - 0040-6090 VL - 595 IS - Part A SP - 200 EP - 208 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-35281 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Beck, Uwe A1 - Hertwig, Andreas A1 - Kormunda, M. A1 - Krause, Andreas A1 - Krüger, Hannes A1 - Lohse, Volkmar A1 - Nooke, Alida A1 - Pavlik, J. A1 - Steinbach, J. T1 - SPR enhanced ellipsometric gas monitoring on thin iron doped tin oxide layers N2 - In this work, thin iron doped tin oxide layers (3–6 nm) were investigated with regard to gas sensitivity by means of surface plasmon resonance (SPR) effect with ellipsometric readout. The experimental set-up was a Kretschmann configuration with gold as metal layer. The sensor system was exposed to different concentrations of methane in the low ppm range and the sensor response of an uncoated gold layer compared to a gold layer coated with iron doped tin oxide. The additional layer effects stability with regard to drift behavior of the sensor and an increase in sensitivity. Furthermore, the sensor is able to detect the toxic gas carbon monoxide in low concentration range (down to 0.5 ppm). The thin layers were investigated by X-ray photoelectron spectroscopy, secondary electron microscopy and spectroscopic ellipsometry. The possible mechanisms taking place on the surface are discussed. KW - Gas sensing KW - SPR effect KW - Iron doped tin oxide KW - Ellipsometry PY - 2011 DO - https://doi.org/10.1016/j.snb.2011.08.036 SN - 0925-4005 SN - 1873-3077 VL - 160 IS - 1 SP - 609 EP - 615 PB - Elsevier CY - Amsterdam [u.a.] AN - OPUS4-24826 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kormunda, M. A1 - Pavlik, J. A1 - Hertwig, Andreas A1 - Nooke, Alida A1 - Krause, Andreas A1 - Beck, Uwe A1 - Steinbach, J. T1 - Magnetron deposited SnO2:Fe films with controlled morphology and a SPR sensor application T2 - PSE 2012 CY - Garmisch-Partenkirchen, Germany DA - 2012-09-10 PY - 2012 AN - OPUS4-26554 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kormunda, M. A1 - Hertwig, Andreas A1 - Beck, Uwe A1 - Fischer, Daniel T1 - Study of magnetron sputtering deposited ultrathin FeSnOx films for Surface Plasmon Resonance sensors towards gas sensing applications N2 - In this study, series of coatings with the goal of sensitising gold SPR sensors towards CO, NH4, etc. were prepared. To better understand the mechanism behind the sensitizing effect and to enable the targeted production of optimized layers, the wide range of coatings was studied by multiple methods from spectroscopic ellipsometry for their dielectric function, by XPS for chemical composition and SEM, TEM to determine their microscopic structure. The coatings were deposited at inert Ar gas and reactive Ar/O2 gas mixture by RF magnetron sputtering or DC pulsed magnetron sputtering with settable RF bias on the substrates. The plasma processes were monitors by mass spectrometry. The metal oxide coatings in SPR sensors have to be prepared reproducible with thickness about 5 nm therefore lower deposition rate conditions were advantages. T2 - THE 14th INTERNATIONAL SYMPOSIUM ON SPUTTERING & PLASMA PROCESSES,ISSP 2017 CY - Kanazawa, Japan DA - 05.07.2017 KW - Surface Plasmon Resonance KW - Magnetron sputtering KW - FeSnOx PY - 2017 AN - OPUS4-43536 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kormunda, M. A1 - Hertwig, Andreas A1 - Beck, Uwe A1 - Fischer, Daniel T1 - Study of magnetron sputtering deposited ultrathin FeSnOx films for Surface Plasmon Resonance sensors towards gas sensing applications N2 - In this study, series of coatings with the goal of sensitising gold SPR sensors towards CO, NH4, etc. were prepared. To better understand the mechanism behind the sensitizing effect and to enable the targeted production of optimized layers, the wide range of coatings was studied by multiple methods from spectroscopic ellipsometry for their dielectric function, by XPS for chemical composition and SEM, TEM to determine their microscopic structure. The coatings were deposited at inert Ar gas and reactive Ar/O2 gas mixture by RF magnetron sputtering or DC pulsed magnetron sputtering with settable RF bias on the substrates. The plasma processes were monitors by mass spectrometry. The metal oxide coatings in SPR sensors have to be prepared reproducible with thickness about 5 nm therefore lower deposition rate conditions were advantages. T2 - THE 14th INTERNATIONAL SYMPOSIUM ON SPUTTERING & PLASMA PROCESSES,ISSP 2017 CY - Kanazawa, Japan DA - 05.07.2017 KW - Surface Plasmon Resonance KW - Magnetron sputtering KW - FeSnOx PY - 2017 AN - OPUS4-43539 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fischer, Daniel A1 - Hertwig, Andreas A1 - Beck, Uwe A1 - Lohse, V. A1 - Negendank, D. A1 - Kormunda, M. A1 - Esser, N. T1 - Thin SnOx films for surface plasmon resonance enhanced ellipsometric gas sensing (SPREE) N2 - Background: Gas sensors are very important in several fields like gas monitoring, safety and environmental applications. In this approach, a new gas sensing concept is investigated which combines the powerful adsorption probability of metal oxide conductive sensors (MOS) with an optical ellipsometric readout. This concept Shows promising results to solve the problems of cross sensitivity of the MOS concept. Results: Undoped tin oxide (SnOx) and iron doped tin oxide (Fe:SnOx) thin add-on films were prepared by magnetron sputtering on the top of the actual surface plasmon resonance (SPR) sensing gold layer. The films were tested for their sensitivity to several gas species in the surface plasmon resonance enhanced (SPREE) gas measurement. It was found that the undoped tin oxide (SnOx) shows higher sensitivities to propane (C3H8) then to carbon monoxide (CO). By using Fe:SnOx, this relation is inverted. This behavior was explained by a change of the amount of binding sites for CO in the layer due to this iron doping. For hydrogen (H2) no such relation was found but the sensing ability was identical for both layer materials. This observation was related to a different sensing mechanism for H2 which is driven by the Diffusion into the layer instead of adsorption on the surface. Conclusion: The gas sensing selectivity can be enhanced by tuning the properties of the thin film overcoating. A relation of the binding sites in the doped and undoped SnOx films and the gas sensing abilities for CO and C3H8 was found. This could open the path for optimized gas sensing devices with different coated SPREE sensors. KW - Doped tin oxide KW - Ellipsometry KW - Gas sensing KW - Surface plasmon KW - Resonance KW - Thin films KW - Transparent conductive oxides PY - 2017 DO - https://doi.org/10.3762/bjnano.8.56 SN - 2190-4286 VL - 8 SP - 522 EP - 529 AN - OPUS4-39391 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fischer, Daniel A1 - Hertwig, Andreas A1 - Beck, Uwe A1 - Negendank, Detlef A1 - Lohse, Volkmar A1 - Kormunda, M. A1 - Esser, N. T1 - Dependence of the optical constants and the performance in the SPREE gas measurement on the thickness of doped tin oxide over coatings N2 - In this study, thickness related changes of the optical properties of doped tin oxide were studied. Two different sets of samples were prepared. The first set was doped with iron or nickel on silicon substrate with thicknesses of 29–56 nm, the second was iron doped on gold/glass substrate with 1.6–6.3 nm. The optical constants were determined by using spectral ellipsometry (SE) followed by modelling of the dielectric function with an oscillator model using Gaussian peaks. The analysis of the optical constants shows a dependence of the refraction and the absorption on the thickness of the doped tin oxide coating. In addition to the tin oxide absorption in the UV, one additional absorption peak was found in the near-IR/red which is related to plasmonic effects due to the doping. This peak shifts from the near-IR to the red part of the visible spectrum and becomes stronger by reducing the thickness, probably due to the formation of metal nanoparticles in this layer. These results were found for two different sets of samples by using the same optical model. Afterwards the second sample set was tested in the Surface Plasmon Resonance Enhanced Ellipsometric (SPREE) gas measurement with CO gas. It was found that the thickness has significant influence on the sensitivity and thus the adsorption of the CO gas. By increasing the thickness from 1.6 nm to 5.1 nm, the sensing ability is enhanced due to a higher coverage of the surface with the over coating. This is explained by the high affinity of CO molecules to the incorporated Fe-nanoparticles in the tin oxide coating. By increasing the thickness further to 6.3 nm, the sensing ability drops because the layer disturbs the SPR sensing effect too much. T2 - 7th International Conference on Spectroscopic Ellipsometry (ICSE-7) DA - 06.06.2016 KW - Surface plasmon resonance KW - Spectroscopic ellipsometry KW - Doped tin oxide KW - Gas sensing KW - Plasmonic absorption PY - 2017 DO - https://doi.org/10.1016/j.apsusc.2016.11.188 SN - 0169-4332 VL - 421, Teil B SP - 480 EP - 486 PB - Elsevier B.V. AN - OPUS4-42692 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kormunda, M. A1 - Hertwig, Andreas A1 - Rysanek, P. A1 - Ivanov, L. T1 - Optical and Electrical Properties of reactive/nonreactive Magnetron Deposited SnZnOxCoatings Annealed at Various Temperatures N2 - ZnSnOx coatings were deposited from two 2in magnetron targets made of ZnO and SnO2 connected to DC pulsed and RF power supplies, respectively. The pure Ar and reactive gas mixture Ar/O2 were used. DC pulsed power applied on ZnO target was kept constant 50W 50kHz, 20% d.c. and the RF power applied on SnO2 target was set to values from 0W (pure ZnO deposited) up to 150W (up to 8 at.% of Sn in films). The deposited films were investigated by multiple techniques as deposited at RT as well as after annealing at temperatures 200o C and 450o C. The lower annealing temperature is still compatible with many of common polymeric substrates. The amount of Sn in the films is proportional to applied RF power on SnO2 target. But there is also significant influence of the post Deposition annealing on the film compositions. The ratio Zn/Sn is reduced by the annealing process. Therefore the annealing is promoting the migration of Sn toward the surface and Zn to inside. Moreover the films deposited in oxygen rich reactive gas mixture does not reduces the resistivity with added Sn in contrary to films deposited in Ar where the resistivity was reduced by 5 orders of magnitudes. The plasma parameters were investigated and mean energies of dominant species were in DC pulsed only about 3eV and DC + RF powered plasma up to 15eV. The expected higher energetic particles in the RF influenced plasma deliver an additional energy to the growing film. Therefore, we observed systematic differences between refractive indexes in the films deposited with low RF powered SnO2 magnetron at RT and post-annealed at 200 ° and practically no difference between RT and post-annealed film at higher RF power above 50 W. The XRD results proved the transitions from an amorphous to more crystalline structure by post-annealing of the films. T2 - PSE 2018 - 16th Conference on Plasma Surface Engineering CY - Garmisch-Partenkirchen, Germany DA - 17.09.2018 KW - Reactive sputtering KW - Plasma diagnostics KW - Optical films KW - TCO PY - 2018 AN - OPUS4-46347 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -