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  • 1.
    Ahlberg, Patrik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Johansson, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Zhang, Zhibin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Lindblad, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Nyberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Defect formation in graphene during low-energy ion bombardment2016In: APL Materials, ISSN 2166-532X, Vol. 4, no 4, article id 046104Article in journal (Refereed)
    Abstract [en]

    This letter reports on a systematic investigation of sputter induced damage in graphene caused by low energy Ar+ ion bombardment. The integral numbers of ions per area (dose) as well as their energies are varied in the range of a few eV's up to 200 eV. The defects in the graphene are correlated to the dose/energy and different mechanisms for the defect formation are presented. The energetic bombardment associated with the conventional sputter deposition process is typically in the investigated energy range. However, during sputter deposition on graphene, the energetic particle bombardment potentially disrupts the crystallinity and consequently deteriorates its properties. One purpose with the present study is therefore to demonstrate the limits and possibilities with sputter deposition of thin films on graphene and to identify energy levels necessary to obtain defect free graphene during the sputter deposition process. Another purpose is to disclose the fundamental mechanisms responsible for defect formation in graphene for the studied energy range.

  • 2.
    Ahlberg, Patrik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Nyberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Zhibin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Toward synthesis of oxide films on graphene with sputtering based processes2016In: Journal of Vacuum Science and Technology B: Nanotechnology and Microelectronics, ISSN 2166-2746, E-ISSN 2166-2754Article in journal (Refereed)
  • 3.
    Austgen, M
    et al.
    Institute of Physics (IA), RWTH Aachen University, Tyskland.
    Koehl, D
    Institute of Physics (IA), RWTH Aachen University, Tyskland.
    Zalden, P
    Institute of Physics (IA), RWTH Aachen University, Tyskland.
    Kubart, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Nyberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Pflug, A
    Fraunhofer IST, Braunschweig, Tyskland.
    Siemers, M
    Fraunhofer IST, Braunschweig, Tyskland.
    Berg, Sören
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Wuttig, M
    Institute of Physics (IA), and, JARA-FIT, RWTH Aachen University, Tyskland.
    Sputter yield amplification by tungsten doping of Al(2)O(3) employing reactive serial co-sputtering: process characteristics and resulting film properties2011In: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 44, no 34, p. 345501-Article in journal (Refereed)
    Abstract [en]

    The deposition rate of reactively sputtered Al(2)O(3) coatings is demonstrated to increase by 80% upon tungsten doping of the used aluminium target. This effect is based on the recoil of the sputtering species at implanted dopants below the target surface and is termed sputter yield amplification. For the investigation of this effect, a novel type of magnetron sputter deposition system is employed that facilitates serial co-sputtering. In this technique doping of the elementary target is enabled by a dynamic sputtering process from an auxiliary cathode. In our case, the rotating aluminium target is dynamically coated with tungsten from this auxiliary cathode. Since the primary target rotates, the auxiliary cathode is placed in series with the primary erosion zone. The deposition rate of Al(2)O(3) can be considerably increased in this process already for very low concentrations of approximately 1% of tungsten in the resulting film. A characterization of the dynamics of reactive sputtering as a function of target rotation speed is performed.

  • 4.
    Bardos, Ladislav
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Barankova, Hana
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Lebedev, Y A
    Nyberg, Tomas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Berg, Sören
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Diamond deposition in a microwave electrode discharge at reduced pressures1997In: DIAMOND AND RELATED MATERIALS, ISSN 0925-9635, Vol. 6, no 2-4, p. 224-229Article in journal (Refereed)
    Abstract [en]

    Diamond deposition on healed Si-substrates was studied under microwave discharge generated by an electrode-antenna either in a ''point-to-plane'' arrangement or in a ''parallel-plane'' arrangement at gas pressures of 1-15 Torr in a mixture of hydrogen wit

  • 5.
    Berg, Sören
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Jonsson, Lars
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Nyberg, Tomas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Katardjiev, Ilia
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Basic Understanding of the Pulsed DC Reactive Sputter Deposition Process1999In: Invited to Second Asian-European Int Conf on Plasma Surface Engineering (AEPSE´99), Beijing, September 15-19, 1999Conference paper (Refereed)
  • 6.
    Berg, Sören
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Nyberg, Tomas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Basic Understanding of Reactive Sputtering Processes2003In: Invited to the AVS 50th National Symposium in Baltimore, Maryland, USA, November 2-7, 2003, 2003Conference paper (Refereed)
  • 7.
    Berg, Sören
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Nyberg, Tomas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Fundamental understanding and modeling of reactive sputtering process2005In: Thin Solid Films, Vol. 476, no 2, p. 215-230Article in journal (Refereed)
  • 8.
    Berg, Sören
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Nyberg, Tomas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Blom, Hans-Olof
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Nender, Claes
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Computer modeling as a tool to predict deposition rate and film composition in the reactive sputtering process1998In: JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS, ISSN 0734-2101, Vol. 16, no 3, p. 1277-1285Article in journal (Refereed)
    Abstract [en]

    Reactive sputtering is a widely used technique to deposit oxides, nitrides, etc. A serious drawback of this technique, however, is the drastic decrease in deposition rate that almost always occurs when depositing compound films as compared to depositing p

  • 9.
    Berg, Sören
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Nyberg, Tomas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Katardjiev, Ilia
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Basic Understanding of the Pulsed DC Reactive Spitter Deposition Process2003In: The 4th Asian-European Int Conf on Plasma Surface Engineering, AEPSE 2003, Jeju City, South Korea, September 28-October 2, 2003, 2003Conference paper (Refereed)
  • 10.
    Berg, Sören
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Nyberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Kubart, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Sputtering yield amplification in reactive sputtering2010Conference paper (Refereed)
  • 11.
    Berg, Sören
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Särhammar, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Nyberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Upgrading the “Berg-model” for reactive sputtering processes2014In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 565, p. 186-192Article, review/survey (Refereed)
    Abstract [en]

    Several phenomena are neglected in the original “Berg model” in order to provide a simple model of the reactive sputtering process. There exist situations, however, where this simplified treatment limits the usefulness of the model. To partly correct for this, we introduce an upgraded version of the basic model. We abandon the simplifying assumption that compound targets are sputter eroded as molecules. Instead, the molecule is split and individual atoms will be sputter ejected. Also, the effect of ionized reactive gas atoms implanted into the target will be considered. We outline how to modify the original model to include these effects. Still, the mathematical treatment is maintained simple so that the new model may serve as an easy-to-understand tutorial of the complex mechanisms of reactive sputtering.

  • 12. Cacucci, Arnaud
    et al.
    Tsiaoussis, Ioannis
    Potin, Valerie
    Imhoff, Luc
    Martin, Nicolas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Nyberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    The interdependence of structural and electrical properties in TiO2/TiO/Ti periodic multilayers2013In: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 61, no 11, p. 4215-4225Article in journal (Refereed)
    Abstract [en]

    Multilayered structures with 14-50 nm periods composed of titanium and two different titanium oxides, TiO and TiO2, were accurately produced by DC magnetron sputtering using the reactive gas pulsing process. The structure and composition of these periodic TiO2/TiO/Ti stacks were investigated by X-ray diffraction and transmission electronic microscopy techniques. Two crystalline phases, hexagonal close packed Ti and face centred cubic TiO, were identified in the metallic-rich sub-layers, whereas the oxygen-rich ones comprised a mixture of amorphous TiO2 and rutile phase. DC electrical resistivity rho measured for temperatures ranging from 300 to 500 K exhibited a metallic-like behaviour (rho(473K) = 1.05 x 10(-5) to 1.45 x 10(-6) Omega m) with a temperature coefficient of resistance ranging from 1.20 x 10(-3) K-1 for the highest period (Lambda = 50.0 nm) down to negative values close to -4.97 x 10(-4) K-1 for the smallest one (Lambda = 14.0 nm). A relationship between the dimensions of periodic layers and their collective electrical resistivity is proposed where the resistivity does not solely depend on the total thickness of the film, but also depends on the chemical composition and thickness of each sub-layer. Charge carrier mobility and concentration measured by the Hall effect were both influenced by the dimension of TiO2/TiO/Ti periods and the density of ionized scattering centres connected to the titanium concentration in the metallic sub-layers.

  • 13.
    Chen, S.
    et al.
    Fudan Univeristy.
    Cui, X-M
    Fudan University.
    Ding, S-J
    Fudan University.
    Sun, Q-Q
    Fudan University.
    Nyberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, W
    Fudan University.
    Novel Zn-Doped Al2O3 Charge Storage Medium for Light-Erasable In-Ga-Zn-O TFT Memory2013In: IEEE Electron Device Letters, ISSN 0741-3106, E-ISSN 1558-0563, Vol. 34, no 8, p. 1008-1010Article in journal (Refereed)
    Abstract [en]

    A novel Zn-doped Al2O3 (ZAO) layer prepared by atomic layer deposition (ALD) is used as the charge storage medium in an In-Ga-Zn-O thin-film-transistor memory. The gate insulating stack of Al2O3/ZAO/Al2O3 is assembled in a single ALD step, and is found to possess a high electron storage capacity due to very deep defect levels. The memory device shows a threshold voltage shift as large as 6.38 V after a +15V/1 ms programming pulse, and quite good charge retention. Once programmed, the memory can be only light erased. The underlying mechanisms are discussed with the assistance of density functional theory calculations.

  • 14. Cui, Xing-Mei
    et al.
    Chen, Sun
    Ding, Shi-Jin
    Sun, Qing-Qing
    Nyberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Wei
    Unique UV-Erasable In-Ga-Zn-O TFT Memory With Self-Assembled Pt Nanocrystals2013In: IEEE Electron Device Letters, ISSN 0741-3106, E-ISSN 1558-0563, Vol. 34, no 8, p. 1011-1013Article in journal (Refereed)
    Abstract [en]

    Semiconducting amorphous indium-gallium-zinc oxide (a-IGZO) films are integrated with an Al2O3/Pt-nanocrystals/ Al2O3 gate-stack to form UV-erasable thin-film transistor (TFT) memory. The threshold voltage (V-th), sub-threshold swing, I-ON/I-OFF ratio, and effective electron mobility of the fabricated devices are 2.1 V, 0.39 V/decade, similar to 10(6), and 8.4 cm(2)/V.s, respectively. A positive V-th shift of 2.25 V is achieved after 1-ms programming at 10 V-th, whereas a negative V-th shift as large as 3.48 V is attained after 5-s UV erasing. In addition, a 10-year memory window of 2.56 V is extrapolated at room temperature. This high-performance a-IGZO TFT memory is suitable for optical touch-panel applications.

  • 15.
    Edoff, Marika
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Lindahl, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Wätjen, Timo
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Nyberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Gas flow sputtering of Cu(In,Ga)Se-2 for thin film solar cells2015In: 2015 IEEE 42ND PHOTOVOLTAIC SPECIALIST CONFERENCE (PVSC), 2015Conference paper (Refereed)
    Abstract [en]

    Gas flow sputtering of Cu(In,Ga)Se-2 (CIGS) from two opposing Cu(In,Ga)Se-2 targets with slightly Cu-poor stoichiometry was performed, using i) selenium only provided by the target and ii) using additional selenium from an elemental source inside the sputtering system. In both cases the composition of the sputtered CIGS film was similar to the target. A sputter process without additional selenium supply led to poor cell results at about 2 % efficiency. After introducing a posttreatment in selenium atmosphere immediately after the sputter deposition, the cell results were dramatically improved to 12 %. With selenium added during the sputtering process, 13.7 % conversion efficiency was obtained without any post treatment. Gas flow sputtering uses a high gas flow to transport the material from the plasma to the growing film, thereby the atoms will be thermalized, similarly to in an evaporation process. Reactant gases can be supplied close to the substrate, outside the plasma, thereby reducing the risk for sputter damage.

  • 16.
    Engelmark, Fredrik
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Westlinder, Jörgen
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Nyberg, Tomas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Berg, Sören
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Experimental and computer simulation studies of the2003In: J Vac Sci Technol, Vol. A21, no 6, p. 1981-1987Article in journal (Refereed)
  • 17.
    Farkas, Balazs
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Nyberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Nanai, Laszlo
    Flexible Thin-Flm Transistors on Planarized Parylene Substrate with Recessed Individual Backgates2014In: Solid-State Electronics, ISSN 0038-1101, E-ISSN 1879-2405, Vol. 94, p. 11-14Article in journal (Refereed)
    Abstract [en]

    With novel design and fabrication techniques, InGaZnO-based thin-film transistors with individual recessed back-gates were fabricated on flexible and transparent polymer substrates. The key components for the fabrication include using a machine park optimized for Si process technology, low-adhesion, room temperature parylene coating, AlOx–ZnOx(Al)-based inorganic lift-off process, and a recessed individual gate concept. Transistors were built to validate the viability of the design as well as aforementioned techniques. The demonstrated approach could open up new design possibilities for cheap, flexible devices, while the recessed-gate concept shows promise towards the use of more brittle layers in our flexible thin-film electronic devices.

  • 18.
    Frisk, Andreas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
    Ali, Hasan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Svedlindh, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Leifer, Klaus
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Andersson, Gabriella
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
    Nyberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Composition, structure and magnetic properties of ultra-thin Fe/Ni multilayers sputter deposited on epitaxial Cu/Si(001)2018In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 646, p. 117-125Article in journal (Refereed)
    Abstract [en]

    Sputter deposited symmetric multilayers of (n Fe)/(n Ni), with individual thicknesses from n = 4 to n = 48 monolayers (ML), were deposited on epitaxial Cu/Si(001), and their microstructural evolution and magnetic properties versus n have been studied. Elemental layering can be seen with transmission electron microscopy down to n = 4 ML layer thickness, although an intermixed region characterized by a finite interface width is found to be present. This width is composed of the interface roughness as well as the interdiffusion between layers, but the relative contributions from these two sources could not be concluded by the techniques used. The measured elemental layering and X-ray reflectivity (XRR) give an upper limit to the interface width which must be smaller than the thinnest layers, 4 ML. Electron energy loss spectroscopy (EELS), depth profiling X-ray photoelectron spectroscopy (XPS) and also XRR reveal that Fe has a higher tendency to mix with Ni than vice versa. XPS does not have the resolution to measure this thin elemental layering: composition variations for n = 8 ML which are clearly seen by EELS are barely resolved by XPS. The structure was determined by X-ray diffraction, and an epitaxial fcc (001) structure is found to be maintained throughout the multilayers up to n less than or similar to 8 ML. For larger n values, relaxation starts by Fe-fcc(001) layers changing into Fe-bcc(110), which is then followed by Ni-fcc(001) changing from (001) to (111) orientation along the growth direction. A decreased total measured magnetic moment for the fully epitaxial multilayers can be explained by the fcc Fe layers being partly anti-ferromagnetic, whereas the relaxed multilayers exhibit the expected magnetic properties of (bcc Fe) +(fcc Ni).

  • 19.
    Gao, Xindong
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Andersson, Joakim
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Kubart, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Nyberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Smith, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Lu, J.
    Hultman, L.
    Kellock, A.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Lavoie, C.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Epitaxy of Ultrathin NiSi2 Films with Predetermined Thickness2011In: Electrochemical and solid-state letters, ISSN 1099-0062, E-ISSN 1944-8775, Vol. 12, p. H268-H270Article in journal (Refereed)
  • 20.
    Gao, Xindong
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Andersson, Joakim
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Kubart, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Nyberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Smith, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Lu, Jun
    Dept of Physics, Chemistry and Biology (IFM), Linköping University.
    Hultman, Lars
    Dept of Physics, Chemistry and Biology (IFM), Linköping University.
    Kellock, Andrew J
    IBM Almaden Research Center, San Jose, CA, USA.
    Zhang, Zhen
    IBM T J Watson Research Center, Yorktown Heights, NY, USA.
    Lavoie, Christian
    IBM T J Watson Research Center, Yorktown Heights, NY, USA.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Epitaxy of Ultrathin NiSi2 Films with Predetermined Thickness2011In: Electrochemical and solid-state letters, ISSN 1099-0062, E-ISSN 1944-8775, Vol. 14, no 7, p. H268-H270Article in journal (Refereed)
    Abstract [en]

    This letter presents a proof-of-concept process for tunable, self-limiting growth of ultrathin epitaxial NiSi2 films on Si (100). The process starts with metal sputter-deposition, followed by wet etching and then silicidation. By ionizing a fraction of the sputtered Ni atoms and biasing the Si substrate, the amount of Ni atoms incorporated in the substrate after wet etching can be controlled. As a result, the thickness of the NiSi2 films is increased from 4.7 to 7.2 nm by changing the nominal substrate bias from 0 to 600 V. The NiSi2 films are characterized by a specific resistivity around 50 mu Omega cm.

  • 21. Hallman, R.
    et al.
    Andersson, J.
    Särhammar, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Nyberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Kubart, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Berg, Sören
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Studies of TiN films deposited by HIPIMS at different substrate temperatures and substrate bias2010Conference paper (Refereed)
  • 22.
    Johansson, Fredrik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Ahlberg, Patrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Lindblad, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Nyberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Minimizing sputter-induced damage during deposition of WS2 onto graphene2017In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 110, no 9, article id 091601Article in journal (Refereed)
    Abstract [en]

    We demonstrate the sputter-deposition of WS2 onto a single-layer graphene film leaving the latter disorder-free. The sputtering process normally causes defects to the graphene lattice and adversely affects its properties. Sputtering of WS2 yields significant amounts of energetic particles, specifically negative S ions, and reflected neutral Ar, and it is therefore used as a model system in this work. The disorder-free sputtering is achieved by increasing the sputteringpressure of Ar thereby shifting the kinetic energy distribution towards lower energies for the impinging particle flux at the substrate. Raman spectroscopy is used to assess the amount of damage to the graphene film. Monte Carlo simulations of the sputteringprocess show that W is completely thermalized already at relatively low sputtering pressure, whereas Ar and S need a comparably higher pressure to thermalize so as to keep the graphene film intact. Apart from becoming completely amorphous at 2.3 mTorr, the graphene filmremains essentially disorder-free when the pressure is increased to 60 mTorr. The approach used here is generally applicable and readily extendable to sputter-deposition of other material combinations onto sensitive substrates. Moreover, it can be used without changing the geometry of an existing sputtering setup.

  • 23.
    Jonsson, Lars
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Nyberg, Tomas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Berg, Sören
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Dynamic simulations of pulsed reactive sputtering processes2000In: J Vac Sci Technol, Vol. A18, no 2, p. 503-508Article in journal (Refereed)
  • 24.
    Jonsson, Lars
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Nyberg, Tomas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Berg, Sören
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Target compound layer formation during reactive sputtering1999In: JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS, ISSN 0734-2101, Vol. 17, no 4, p. 1827-1831Article in journal (Refereed)
    Abstract [en]

    It is well known that a compound layer may form at the target surface during reactive sputtering. However, the significance of this layer for the response to a change in target conditions has so far not been carefully investigated. The standard model for

  • 25.
    Jonsson, Lars
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Nyberg, Tomas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Berg, Sören
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Target Compound Layer Formation during Reactive Sputtering1998In: Presented at AVS 45th National Symposium in Baltimore, Maryland, USA, November 2-6, 1998Conference paper (Refereed)
  • 26.
    Jonsson, Lars
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Nyberg, Tomas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Katardjiev, Ilia
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Berg, Sören
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Frequency response in pulsed DC reactive sputtering processes2000In: Thin Solid Films, Vol. 365, p. 43-48Article in journal (Refereed)
  • 27.
    Kappertz, Oliver
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Kubart, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Nyberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Berg, Sören
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Advanced Process Modelling of the Rotating Magnetron2006Conference paper (Refereed)
  • 28.
    Kappertz, Oliver
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Kubart, Tomas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Nyberg, Tomas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Berg, Sören
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Severin, Daniel
    Wüttig, Mattias
    Ion Implantation Effects in Reactive Sputter Deposition2005In: Presented at the 14th Int. Conf. on Surface Modification of Materials by Ion Beams (SMMIB’05) in Kusadasi, Turkey, 4-9 September, 2005Conference paper (Other scientific)
  • 29.
    Kappertz, Oliver
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Nyberg, Tomas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Rosén, Daniel
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Berg, Sören
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Influence of rotating magnets on hysteresis in reactive sputtering2004In: Society of Vacuum Coaters, 7th Annual Technical Conference Proceedings, April, 2004Conference paper (Other scientific)
  • 30.
    Kappertz, Oliver
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Nyberg, Tomas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Rosén, Daniel
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Katardjiev, Ilia
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Berg, Sören
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    A Simplified Treatment of Target Implantation Effects in Reactive Sputtering2004In: The International Conference on Metallurgical Coatings and Thin Films in San Diego, USA, 2004Conference paper (Refereed)
  • 31.
    Kubart, Tomas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Aiempanakit, M.
    Andersson, J.
    Nyberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Berg, Sören
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Helmersson, U.
    Studies of hysteresis effect in reactive HiPIMS deposition of oxides2010Conference paper (Refereed)
  • 32.
    Kubart, Tomas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Aiempanakit, M
    Plasma & Coatings Physics Division, IFM, materials Physics, Linköping University, Linköping.
    Andersson, Joakim
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Nyberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Berg, Sören
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Helmersson, U
    Plasma & Coatings Physics Division, IFM, materials Physics, Linköping University, Linköping.
    Studies of hysteresis effect in reactive HiPIMS deposition of oxides2011In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 205, no Suppl. 2, p. S303-S306Article in journal (Refereed)
    Abstract [en]

    High power impulse magnetron sputtering (HiPIMS) has proven to be capable of substantial improvement of the quality of deposited coatings. Lately, there have been a number of reports indicating that the hysteresis effect may be reduced in HiPIMS mode resulting in an increase of the deposition rate of stoichiometric compound as compared to a direct current magnetron sputtering process in oxide mode. In this contribution, we have studied the hysteresis behaviour of Ti metal targets sputtered in Ar + O(2) mixtures. For fixed pulse on time and a constant average power, there is an optimum frequency minimizing the hysteresis. The effect of gas dynamics was analyzed by measurements of the gas refill time and rarefaction. Results indicate that the gas rarefaction may be responsible for the observed hysteresis behaviour. The results are in agreement with a previous study of Al oxide reactive process.

  • 33.
    Kubart, Tomas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Arapan, Sergiu
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Skorodumova, Natalia V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Nyberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Berg, Sören
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Molecular dynamics simulations of low energy Ar sputtering of TiO2 surfaces2010Conference paper (Refereed)
  • 34.
    Kubart, Tomas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Depla, D
    Martin, David
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Nyberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Berg, Sören
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    On the high rate reactive sputtering of substoichiometric titanium oxide targets2007Conference paper (Refereed)
  • 35.
    Kubart, Tomas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Depla, Diederik
    Univ Ghent, Dept Solid State Sci, B-9000 Ghent, Belgium.
    Martin, David
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Nyberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Berg, Sören
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    High rate reactive magnetron sputter deposition of titanium oxide2008In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, ISSN 1, Vol. 92, no 22, p. 221501-Article in journal (Refereed)
    Abstract [en]

    A systematic experimental study of reactive sputtering from substoichiometric targets of TiOx with x ranging from 0 to 1.75 is reported. Experimental results are compared with results from modeling. The developed model describes the observed behavior and explains the origins of the unexpectedly high deposition rate. The behavior is shown to originate from the presence of titanium suboxides at the target surface caused by preferential sputtering of the oxide. The model can be used for optimization of the target composition with respect to the deposition rate and film composition in a stable hysteresis-free reactive sputtering process.

  • 36.
    Kubart, Tomas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Nyberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Liljeholm, Lina
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Depla, D.
    Berg, Sören
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Influence of the target composition on reactively sputtered titanium oxide films2009In: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 83, no 10, p. 1295-1298Article in journal (Refereed)
    Abstract [en]

    Titanium dioxide thin films have many interesting properties and are used in various applications. High refractive index of titania makes it attractive for the glass coating industry, where it is used in low-emissivity and antireflective coatings. Magnetron sputtering is the most common deposition technique for large area coatings and a high deposition rate is therefore of obvious interest. It has been shown previously that high rate can be achieved using substoichiometric targets. This work deals with reactive magnetron sputtering of titanium oxide films from TiOx targets with different oxygen contents. The deposition rate and hysteresis behaviour are disclosed. Films were prepared at various oxygen flows and all films were deposited onto glass and silicon substrates with no external heating. The elemental compositions and structures of deposited films were evaluated by means of X-ray photoelectron spectroscopy, elastic recoil detection analysis and X-ray diffraction. All deposited films were X-ray amorphous. No significant effect of the target composition on the optical properties of coatings was observed. However, the residual atmosphere is shown to contribute to the oxidation of growing films.

  • 37.
    Kubart, Tomas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Kappertz, Oliver
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Nyberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Berg, Sören
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Dynamic behaviour of the reactive sputtering process2006In: Thin Solid Films, Vol. 515, p. 421-424Article in journal (Refereed)
  • 38.
    Kubart, Tomas
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Kappertz, Oliver
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Nyberg, Tomas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Berg, Sören
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Dynamic Behaviour of the Reactive Sputtering Process2005In: Presented at 13th International Congress on Thin Films 8th International Conference on Atomically Controlled Surfaces, Interfaces & Nanostructures (ICTF13/ACSIN8) in Stockholm, Sweden, 19-23 June 2005, 2005Conference paper (Other scientific)
  • 39.
    Kubart, Tomas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Kappertz, Oliver
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Nyberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Berg, Sören
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Dynamic Modelling of Reactive Magnetron Sputtering2006Conference paper (Refereed)
  • 40.
    Kubart, Tomas
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Kappertz, Oliver
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Nyberg, Tomas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Berg, Sören
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Experimental Studies of the Dynamic Behavior of the Reactive Sputtering Process2005In: Presented at the 5th Asian-European Int. Conf. on Plasma Surface Engineering (AEPSE 2005) in Qingdao City, China, 12-16 September, 2005Conference paper (Other scientific)
  • 41.
    Kubart, Tomas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Nyberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Berg, Soren
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Austgen, Michael
    RWTH Aachen.
    Koehl, Dominik
    RWTH Aachen.
    Wuttig, Matthias
    RWTH Aachen.
    Pflug, Andreas
    Fraunhofer IST.
    Siemers, Michael
    Fraunhofer IST.
    Serial magnetron co-sputtering: Sputtering yield amplification and process modelling2011In: E-MRS 2011 Spring Meeting, 2011Conference paper (Refereed)
  • 42.
    Kubart, Tomas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Nyberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Berg, Sören
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    High rate reactive magnetron sputtering of oxides using sputtering yield amplification2012Conference paper (Refereed)
    Abstract [en]

    In this contribution, we summarize our work on increasing the deposition rate in reactive magnetron sputtering by sputtering yield amplification. Modelling of the sputtering process predicts that a very high deposition rate increase by more than 100 % may be achieved for oxides. Comparable values were measured experimentally using a setup suitable for up-scaling.

    In sputtering yield amplification the target is doped with a heavy dopant in order to reflect the recoils created in a collision cascade towards the surface and thus increase the number of atoms sputtered from the surface. In order to realize the process, an experimental system for serial co-sputtering has been built and used for experimental studies. The dopants are introduced from an auxiliary cathode onto the primary rotating target and incorporated into the target surface by recoil implantation during sputtering. A necessary requirement for suitable doping elements is high atomic mass. Another important parameter is the surface binding energy as demonstrated by comparison of W and Bi, two heavy elements with very different surface binding energies. Using a dynamical model of the sputtering process, the performance of various doping elements is evaluated.

    Reactive sputtering of Al and Ti targets with W and Bi doping was performed.  The deposition rate of Al2O3 can be increased by 80 % by W doping of the Al target in very good agreement with predictions. For TiO2, however, an increase by more than 100 % was observed, substantially higher than predicted. Finally, the optical properties of W doped Al2O3 and TiO2 thin films are briefly discussed.

  • 43.
    Kubart, Tomas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Nyberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Berg, Sören
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Modelling of low energy ion sputtering from oxide surfaces2010In: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 43, no 20, p. 205204-Article in journal (Refereed)
    Abstract [en]

    The main aim of this work is to present a way to estimate the values of surface binding energy for oxides. This is done by fitting results from the binary collisions approximation code Tridyn with data from the reactive sputtering processing curves, as well as the elemental composition obtained from x-ray photoelectron spectroscopy (XPS). Oxide targets of Al, Ti, V, Nb and Ta are studied. The obtained surface binding energies are then used to predict the partial sputtering yields. Anomalously high sputtering yield is observed for the TiO 2 target. This is attributed to the high sputtering yield of Ti lower oxides. Such an effect is not observed for the other studied metals. XPS measurement of the oxide targets confirms the formation of suboxides during ion bombardment as well as an oxygen deficient surface in the steady state. These effects are confirmed from the processing curves from the oxide targets showing an elevated sputtering rate in pure argon.

  • 44.
    Kubart, Tomas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Nyberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Berg, Sören
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Preferential Sputtering of Oxides and Target Design for Stable Reactive Magnetron Deposition of Oxides2009Conference paper (Refereed)
  • 45.
    Kubart, Tomas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Nyberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Berg, Sören
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Pflug, A.
    Austgen, M.
    Koehl, D.
    Wuttig, M.
    Sputtering Yield Amplification in Reactive Serial Co-Sputtering2010Conference paper (Refereed)
  • 46.
    Kubart, Tomas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Nyberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Pflug, A.
    Fraunhofer IST.
    Siemers, M.
    Fraunhofer IST.
    Austgen, M.
    RWTH Aachen.
    Koehl, D.
    RWTH Aachen.
    Wuttig, M.
    RWTH Aachen.
    Berg, Sören
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Modelling of sputtering yield amplification effect in reactive deposition of oxides2010In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 204, no 23, p. 3882-3886Article in journal (Refereed)
    Abstract [en]

    Many reactive sputter deposition applications require high deposition rates. The primary limiting parameters in magnetron sputtering are the target power dissipation and sputtering yields of the target elements. In reactive deposition of oxides, the deposition rate is of particular interest due to the low sputtering yield of most commonly used oxides. Traditional high rate techniques rely on a feedback control of the oxygen partial pressure to prevent formation of oxide on the target and hence enable operation in the transition area. An alternative approach, based on target doping, is presented in this paper.By doping the sputtering target with heavy elements, it is possible to substantially enhance the sputtering yield and hence the deposition rate. Simulations of the partial sputtering yield values for aluminium from doped targets sputtered in reactive atmosphere have been carried out. The Monte Carlo based TRIDYN computer code has been used for simulations. The program has been used to find out optimum alloying conditions to obtain maximum partial sputtering yield for deposition of Al2O3. Our simulations indicate that the sputtering yield amplification in reactive sputtering may lead to much higher relative deposition rate increase than in a nonreactive case. The highest relative increase may be achieved in the transition region but substantial increase is predicted also in the oxide mode.

  • 47.
    Kubart, Tomas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Nyberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Polcar, T
    Cavaleiro, A
    Malainho, E
    Vasilevsky, M
    Decorative Oxide Coatings: Colour Control by Compositional Gradient2009In: E-MRS 2009, Spring Meeting in Strasbourgh, France, June 8-12, 2009, 2009Conference paper (Refereed)
  • 48.
    Kubart, Tomas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Polcar, Tomas
    Kappertz, Oliver
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Parreira, Nuno
    Nyberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Berg, Sören
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Cavaleiro, Albano
    Modelling of Magnetron Sputtering of Tungsten Oxide with Reactive Gas Pulsing2007In: Plasma Processes and Polymers, ISSN 1612-8850, Vol. 4, p. S522-S526Article in journal (Refereed)
    Abstract [en]

    Reactive sputtering is one of the most commonly employed processes for the deposition of thin films. However, the range of applications is limited by inherent instabilities, which necessitates the use of a complex feedback control of reactive gas (RG) partial pressure. Recently pulsing of the RG has been suggested as a possible alternative. In this report, the concept of periodically switching the RG flow between two different values is applied to the deposition of tungsten oxide. The trends in the measured time dependent RG pressure and discharge voltage are reproduced by a dynamical model developed for this process. Furthermore, the model predicts the compositional depth profile of the deposited film reasonably well, and in particular helps to understand the formation of the interfaces in the resulting multi-layer film.

  • 49.
    Kubart, Tomas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Schmidt, R. M.
    Austgen, M.
    Nyberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Pflug, A.
    Siemers, M.
    Wuttig, M.
    Berg, Sören
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Modelling of sputtering yield amplification in serial reactive magnetron co-sputtering2012In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 206, no 24, p. 5055-5059Article in journal (Refereed)
    Abstract [en]

    Serial magnetron co-sputtering can be used to increase the deposition rate in reactive deposition of thin films. The increase in deposition rate is achieved by sputtering yield amplification through doping the sputtering target by a heavy element. The dopant is introduced by means of sputtering from an auxiliary target onto a rotating primary magnetron. During sputtering of the primary target, the dopant is implanted into the target surface. Here we present a model describing the serial co-sputtering technique. The model is based on the binary collision approximation and takes into account the dynamical sputtering and mixing at the target surface. As an example, W and Bi doping in reactive sputter deposition of Al2O3 is analyzed. W is shown to be very efficient dopant which can increase the deposition rate for oxide up to 100% with 1.6 at.% of W in the resulting coating. Doping by Bi is not very effective due to the low surface binding energy of Bi. The simulations show that sputtering yield amplification can be realized in the serial co-sputtering setup with rotating magnetrons.

  • 50.
    Kubart, Tomas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Trinh, D. H.
    Liljeholm, L.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Hultman, L.
    Hogberg, H.
    Nyberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Berg, Sören
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Experiments and modeling of dual reactive magnetron sputtering using two reactive gases2008In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 26, no 4, p. 565-570Article in journal (Refereed)
    Abstract [en]

    Reactive sputtering from two elemental targets, aluminum and zirconium, with the addition of two reactive gases, oxygen and nitrogen, is studied experimentally as well as theoretically. The complex behavior of this process is observed and explained. It is shown that the addition of oxygen to a constant supply of nitrogen significantly changes the relative content of aluminum with respect to zirconium in the film. Moreover, it is concluded that there is substantially more oxygen than nitrogen in the films even when the oxygen supply is significantly lower than the nitrogen supply. It is further shown that the addition of a certain minimum constant flow of nitrogen reduces, and eventually eliminates, the hysteresis with respect to the oxygen supply. It is concluded that the presented theoretical model for the involved reactions and mass balance during reactive sputtering of two targets in two reactive gases is in qualitative agreement with the experimental results and can be used to find optimum processing conditions for deposition of films of a desired composition.

123 1 - 50 of 112
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