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  • 1.
    Alami, Jones
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics. Linköping University, The Institute of Technology.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Emmerlich, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Wilhelmsson, O.
    Department of Materials Chemistry, The Ångström Laboratory, Uppsala University, Uppsala, Sweden.
    Jansson, U.
    Department of Materials Chemistry, The Ångström Laboratory, Uppsala University, Uppsala, Sweden.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Helmersson, Ulf
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics. Linköping University, The Institute of Technology.
    High-power impulse magnetron sputtering of Ti-Si-C thin films from a Ti3SiC2 compound target2006In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 515, no 4, 1731-1736 p.Article in journal (Refereed)
    Abstract [en]

    We have deposited Ti-Si-C thin films using high-power impulse magnetron sputtering (HIPIMS) from a Ti3SiC2 compound target. The as-deposited films were composite materials with TiC as the main crystalline constituent. X-ray diffraction and photoelectron spectroscopy indicated that they also contained amorphous SiC, and for films deposited on inclined substrates, crystalline Ti5Si3Cx. The film morphology was dense and flat, while films deposited with dc magnetron sputtering under comparable conditions were rough and porous. Due to the high degree of ionization of the sputtered species obtained in HIPIMS, it is possible to control the film composition, in particular the C content, by tuning the substrate inclination angle, the Ar process pressure, and the bias voltage.

  • 2.
    Alling, Björn
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Armiento, Rickard
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Rosén, Johanna
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    A theoretical investigation of mixing thermodynamics, age-hardening potential, and electronic structure of ternary (M1-xMxB2)-M-1-B-2 alloys with AlB2 type structure2015In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 5Article in journal (Refereed)
    Abstract [en]

    Transition metal diborides are ceramic materials with potential applications as hard protective thin films and electrical contact materials. We investigate the possibility to obtain age hardening through isostructural clustering, including spinodal decomposition, or ordering-induced precipitation in ternary diboride alloys. By means of first-principles mixing thermodynamics calculations, 45 ternary (M1-xMxB2)-M-1-B-2 alloys comprising (MB2)-B-i (M-i = Mg, Al, Sc, Y, Ti, Zr, Hf, V, Nb, Ta) with AlB2 type structure are studied. In particular Al1-xTixB2 is found to be of interest for coherent isostructural decomposition with a strong driving force for phase separation, while having almost concentration independent a and c lattice parameters. The results are explained by revealing the nature of the electronic structure in these alloys, and in particular, the origin of the pseudogap at E-F in TiB2, ZrB2, and HfB2.

  • 3.
    Broitman, Esteban
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Furlan, Andrej
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Geuorguiev, G. K.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Czigany, Zsolt
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Structural and Mechanical Properties of CNx and CPx Thin Solid Films2012In: Key Engineering Materials, ISSN 1013-9826, E-ISSN 1662-9795, Vol. 488-489, 581-584 p.Article in journal (Refereed)
    Abstract [en]

    The inherent resiliency, hardness and relatively low friction coefficient of the fullerene-like (FL) allotrope of carbon nitride (CNx) thin solid films give them potential in numerous tribological applications. In this work, we study the substitution of N with P to grow FL-CPx to achieve better cross- and inter-linking of the graphene planes, improving thus the materials mechanical and tribological properties. The CNx and CPx films have been synthesized by DC magnetron sputtering. HRTEM have shown the CPx films exhibit a short range ordered structure with FL characteristics for substrate temperature of 300 degrees C and for a phosphorus content of 10-15 at.%. These films show better mechanical properties in terms of hardness and resiliency compared to those of the FL-CNx films. The low water adsorption of the films is correlated to the theoretical prediction for low density of dangling bonds in both, CNx and CPx. First-principles calculations based on Density Functional Theory (DFT) were performed to provide additional insight on the structure and bonding in CNx, CPx and a-C compounds.

  • 4.
    Broitman, Esteban
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Tengdelius, Lina
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Hangen, Ude D.
    Hysitron Inc., Minneapolis, Minnesota, USA.
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    High-temperature nanoindentation of epitaxial ZrB2 thin films2016In: Scripta Materialia, ISSN 1359-6462, E-ISSN 1872-8456, Vol. 124, 117-120 p.Article in journal (Refereed)
    Abstract [en]

    We use in-situ heated nanoindentation to investigate the high-temperature nanomechanical properties of epitaxial and textured ZrB2 films deposited by magnetron sputtering. Epitaxial films deposited on 4H-SiC(0001) show a hardness decrease from 47 GPa at room temperature to 33 GPa at 600 °C, while the reduced elastic modulus does not change significantly. High resolution electron microscopy (HRTEM) with selected area electron diffraction of the indented area in a 0001-textured film reveals a retained continuous ZrB2 film and no sign of crystalline phase transformation, despite massive deformation of the Si substrate. HRTEM analysis supports the high elastic recovery of 96% in the films.

    The full text will be freely available from 2018-07-13 14:36
  • 5.
    Chubarov, M.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology. Not Found: Linkoping Univ, Dept Phys Chem and Biol, SE-58183 Linkoping, Sweden .
    Pedersen, Henrik
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Czigany, Zs.
    Hungarian Academic Science, Hungary .
    Henry, Anne
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Chemical vapour deposition of epitaxial rhombohedral BN thin films on SiC substrates2014In: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 16, no 24, 5430-5436 p.Article in journal (Refereed)
    Abstract [en]

    Epitaxial growth of rhombohedral boron nitride (r-BN) on different polytypes of silicon carbide (SiC) is demonstrated using thermally activated hot-wall chemical vapour deposition and triethyl boron and ammonia as precursors. With respect to the crystalline quality of the r-BN films, we investigate the influence of the deposition temperature, the precursor ratio (N/B) and the addition of a minute amount of silicon to the gas mixture. From X-ray diffraction and transmission electron microscopy, we find that the optimal growth temperature for epitaxial r-BN on the Si-face of the SiC substrates is 1500 degrees C at a N/B ratio of 642 and silicon needs to be present not only in the gas mixture during deposition but also on the substrate surface. Such conditions result in the growth of films with a c-axis identical to that of the bulk material and a thickness of 200 nm, which is promising for the development of BN films for electronic applications.

  • 6.
    Chubarov, M.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Pedersen, Henrik
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Filippov, Stanislav
    Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials. Linköping University, The Institute of Technology.
    Engelbrecht, J.A. A.
    Nelson Mandela Metropolitan University, South Africa .
    O'Connel, J.
    Nelson Mandela Metropolitan University, South Africa .
    Henry, Anne
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Boron nitride: A new photonic material2014In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 439, 29-34 p.Article in journal (Refereed)
    Abstract [en]

    Rhombohedral boron nitride (r-BN) layers were grown on sapphire substrate in a hot-wall chemical vapor deposition reactor. Characterization of these layers is reported in details. X-ray diffraction (XRD) is used as a routine characterization tool to investigate the crystalline quality of the films and the identification of the phases is revealed using detailed pole figure measurements. Transmission electron microscopy reveals stacking of more than 40 atomic layers. Results from Fourier Transform InfraRed (FTIR) spectroscopy measurements are compared with XRD data showing that FTIR is not phase sensitive when various phases of sp(2)-BN are investigated. XRD measurements show a significant improvement of the crystalline quality when adding silicon to the gas mixture during the growth; this is further confirmed by cathodoluminescence which shows a decrease of the defects related luminescence intensity.

  • 7.
    Chubarov, M.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Pedersen, Henrik
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Filippov, Stanislav
    Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials. Linköping University, The Institute of Technology.
    Engelbrecht, J.A. A.
    Nelson Mandela Metropolitan University, Port Elizabeth, South Africa.
    O'Connel, J.
    Nelson Mandela Metropolitan University, Port Elizabeth, South Africa.
    Henry, Anne
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Characterization of Boron Nitride Thin Films2013Conference paper (Refereed)
    Abstract [en]

    Rhombohedral Boron Nitride layers were grown on sapphire substrate in a hot-wall CVD reactor. The characterization of those layers is reported and the results are discussed in correlation with the various growth parameters used.

  • 8.
    Chubarov, Mikhail
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Pedersen, Henrik
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Czigany, Zsolt
    Hungarian Academic Science, Hungary .
    Andersson, Sven G.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Henry, Anne
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Nucleation and initial growth of sp2-BNon α-Al2O3 and SiC by chemical vapour deposition2014Manuscript (preprint) (Other academic)
    Abstract [en]

    Knowledge on thin films evolution from the early stages of growth is important for the control of quality and properties of the film. Here we present study of the early growth stages and evolution of the crystalline structure of sp2 hybridised Boron Nitride (BN) thin films deposited by chemical vapour deposition from triethyl boron and ammonia. Nucleation of hexagonal BN (h-BN) is observed already at 1200 °C on α-Al2O3 substrate with an AlN buffer layer (AlN/α-Al2O3) while no formation of h-BN is detected when the growth is done on 6H-SiC in a growth temperature range between 1200 °C and 1700 °C. We demonstrate that h-BN grows on AlN/α-Al2O3 exhibiting a layer-by-layer growth mode up to ca. 4 nm followed by a transition to r-BN growth when grown at 1500 °C. The following r-BN growth is suggested to proceed with mixed layer-by-layer and island growth mode; after a thin continuous layer of r-BN, islands formation is favoured leading to a twinned r-BN structure of the film. We find that h-BN does not grow on 6H-SiC substrates instead r-BN nucleates and grows directly as a twinned crystal. The twinning is found to be suppressed by a surface preparation of the SiC substrate with SiH4 prior to BN growth. These results open up for a more controlled epitaxial growth of sp2-BN for future electronic applications.

  • 9.
    Chubarov, Mikhail
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Pedersen, Henrik
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Czigany, Zsolt
    Hungarian Academic Science, Hungary .
    Garbrecht, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Henry, Anne
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Polytype pure sp2-BN thin films as dictated by the substrate crystal structure2015In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 27, no 5, 1640-1645 p.Article in journal (Refereed)
    Abstract [en]

    Boron nitride (BN) is a promising semiconductor material, but its current exploration is hampered by difficulties in growth of single crystalline phase-pure thin films. We compare the growth of sp2-BN by chemical vapor deposition on (0001) 6H-SiC and on (0001) α-Al2O3 substrates with an AlN buffer layer. Polytype-pure rhombohedral BN (r-BN) with a thickness of 200 nm is observed on SiC whereas hexagonal BN (h-BN) nucleates and grows on the AlN buffer layer. For the latter case after a thickness of 4 nm, the h-BN growth is followed by r-BN growth to a total thickness of 200 nm. We find that the polytype of the sp2-BN films is determined by the ordering of Si-C or Al-N atomic pairs in the underlying crystalline structure (SiC or AlN). In the latter case the change from h-BN to r-BN is triggered by stress relaxation. This is important for the development of BN semiconductor device technology.

  • 10.
    Chubarov, Mikhail
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Pedersen, Henrik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Henry, Anne
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    On the effect of silicon in CVD of sp2 hybridized boron nitride thin films2013In: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 15, no 3, 455-458 p.Article in journal (Refereed)
    Abstract [en]

    The influence of silicon on the growth of epitaxial rhombohedral boron nitride (r-BN) films deposited on sapphire (0001) by chemical vapor deposition is investigated. X-ray diffraction measurements and secondary ion mass spectrometry show that silicon favors the formation of r-BN and is incorporated into the film.

  • 11.
    Chubarov, Mikhail
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering.
    Pedersen, Henrik
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Henry, Anne
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Czigany, Zsolt
    Hungarian Academic Science, Hungary.
    Initial stages of growth and the influence of temperature during chemical vapor deposition of sp(2)-BN films2015In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 33, no 6, 061520- p.Article in journal (Refereed)
    Abstract [en]

    Knowledge of the structural evolution of thin films, starting by the initial stages of growth, is important to control the quality and properties of the film. The authors present a study on the initial stages of growth and the temperature influence on the structural evolution of sp(2) hybridized boron nitride (BN) thin films during chemical vapor deposition (CVD) with triethyl boron and ammonia as precursors. Nucleation of hexagonal BN (h-BN) occurs at 1200 degrees C on alpha-Al2O3 with an AlN buffer layer (AlN/alpha-Al2O3). At 1500 degrees C, h-BN grows with a layer-by-layer growth mode on AlN/alpha-Al2O3 up to similar to 4 nm after which the film structure changes to rhombohedral BN (r-BN). Then, r-BN growth proceeds with a mixed layer-by-layer and island growth mode. h-BN does not grow on 6H-SiC substrates; instead, r-BN nucleates and grows directly with a mixed layer-by-layer and island growth mode. These differences may be caused by differences in substrate surface temperature due to different thermal conductivities of the substrate materials. These results add to the understanding of the growth process of sp(2)-BN employing CVD. (C) 2015 American Vacuum Society.

  • 12.
    Chubarov, Mikhail
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Pedersen, Henrik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Jensen, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Henry, Anne
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Growth of High Quality Epitaxial Rhombohedral Boron Nitride2012In: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 12, no 6, 3215-3220 p.Article in journal (Refereed)
    Abstract [en]

    Epitaxial growth of sp(2)-hybridized boron nitride (sp(2) BN) films on sapphire substrates is demonstrated in a hot wall chemical vapor deposition reactor at the temperature of 1500 degrees C, using triethyl boron and ammonia as precursors. The influence of the main important process parameters, temperature, N/B ratio, B/H-2 ratio, and carrier gas composition on the quality of the grown layers is investigated in detail. X-ray diffraction shows that epitaxial rhombohedral BN (r-BN) film can be deposited only in a narrow process parameter window; outside this window either turbostratic-BN or amorphous BN is favored if BN is formed. In addition, a thin strained AlN buffer layer is needed to support epitaxial growth of r-BN film on sapphire since only turbostratic BN is formed on sapphire substrate. The quality of the grown film is also affected by the B/H-2 ratio as seen from a change of the spacing between the basal planes as revealed by X-ray diffraction. Time-of-flight elastic recoil detection analysis shows an enhancement of the C and O impurities incorporation at lower growth temperatures. The gas phase chemistry for the deposition is discussed as well as the impact of the growth rate on the quality of the BN film.

  • 13.
    Cubarovs, Mihails
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Pedersen, Henrik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Darakchieva, Vanya
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Jens, Jensen
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Persson, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Henry, Anne
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Epitaxial CVD growthof sp2-hybridized boron nitrideusing aluminum nitride as buffer layer2011In: Physica Status Solidi. Rapid Research Letters, ISSN 1862-6254, E-ISSN 1862-6270, Vol. 5, no 10-11, 397-399 p.Article in journal (Refereed)
    Abstract [en]

    Epitaxial growth of sp2-hybridized boron nitride (BN) using chemical vapour deposition, with ammonia and triethyl boron as precursors, is enabled on sapphire by introducing an aluminium nitride (AlN) buffer layer. This buffer layer is formed by initial nitridation of the substrate. Epitaxial growth is verified by X-ray diffraction measurements in Bragg–Brentano configuration, pole figure measurements and transmission electron microscopy. The in-plane stretching vibration of sp2-hybridized BN is observed at 1366 cm–1 from Raman spectroscopy. Time-of-flight elastic recoil detection analysis confirms almost perfect stoichiometric BN with low concentration of carbon, oxygen and hydrogen contaminations.

  • 14.
    Eklund, Per
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Beckers, Manfred
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Frodelius, Jenny
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Magnetron sputtering of Ti3SiC2 thin films from a Ti3SiC2 compound target2007In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 25, no 5, 1381-1388 p.Article in journal (Refereed)
    Abstract [en]

    Ti3 Si C2 thin films were synthesized by magnetron sputtering from Ti3 Si C2 and Ti targets. Sputtering from a Ti3 Si C2 target alone resulted in films with a C content of ∼50 at. % or more, due to gas-phase scattering processes and differences in angular and energy distributions between species ejected from the target. Addition of Ti to the deposition flux from a Ti3 Si C2 target is shown to bind the excess C in Ti Cx intergrown with Ti3 Si C2 and Ti4 Si C3. Additionally, a substoichiometric Ti Cx buffer layer is shown to serve as a C sink and enable the growth of Ti3 Si C2.

  • 15.
    Eklund, Per
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Beckers, Manfred
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Jansson, Ulf
    Uppsala University.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    The M(n+1)AX(n) phases: Materials science and thin-film processing2010In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 518, no 8, 1851-1878 p.Article, review/survey (Refereed)
    Abstract [en]

    This article is a Critical review of the M(n + 1)AX(n) phases ("MAX phases", where n = 1, 2, or 3) from a materials science perspective. MAX phases are a class of hexagonal-structure ternary carbides and nitrides ("X") of a transition metal ("M") and an A-group element. The most well known are Ti2AlC, Ti3SiC2, and Ti4AlN3. There are similar to 60 MAX phases with at least 9 discovered in the last five years alone. What makes the MAX phases fascinating and potentially useful is their remarkable combination of chemical, physical, electrical, and mechanical properties, which in many ways combine the characteristics of metals and ceramics. For example, MAX phases are typically resistant to oxidation and corrosion, elastically stiff, but at the same time they exhibit high thermal and electrical conductivities and are machinable. These properties stem from an inherently nanolaminated crystal structure, with M1 + nXn slabs intercalated with pure A-element layers. The research on MAX phases has been accelerated by the introduction of thin-film processing methods. Magnetron sputtering and arc deposition have been employed to synthesize single-crystal material by epitaxial growth, which enables studies of fundamental material properties. However, the surface-initiated decomposition of M(n + 1)AX(n) thin films into MX compounds at temperatures of 1000-1100 degrees C is much lower than the decomposition temperatures typically reported for the corresponding bulk material. We also review the prospects for low-temperature synthesis, which is essential for deposition of MAX phases onto technologically important substrates. While deposition of MAX phases from the archetypical Ti-Si-C and Ti-Al-N systems typically requires synthesis temperatures of similar to 800 degrees C, recent results have demonstrated that V2GeC and Cr2AlC can be deposited at similar to 450 degrees C. Also, thermal spray of Ti2AlC powder has been used to produce thick coatings. We further treat progress in the use of first-principle calculations for predicting hypothetical MAX phases and their properties. Together with advances in processing and materials analysis, this progress has led to recent discoveries of numerous new MAX phases such as Ti4SiC3, Ta4AlC3. and Ti3SnC2. Finally, important future research directions are discussed. These include charting the unknown regions in phase diagrams to discover new equilibrium and metastable phases, as well as research challenges in understanding their physical properties, such as the effects of anisotropy, impurities, and vacancies on the electrical properties, and unexplored properties such as Superconductivity, magnetism, and optics.

  • 16.
    Eklund, Per
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Emmerlich, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Wilhelmsson, Ola
    Uppsala universitet.
    Jansson, Ulf
    Uppsala universitet.
    Isberg, Peter
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Synthesis and characterization of Ti-Si-C compounds for electrical contact applications2005In: IEEE Holm Conference on Electrical Contacts,2005, Piscataway: IEEE , 2005, 277-283 p.Conference paper (Refereed)
  • 17.
    Eklund, Per
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Emmerlich, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Wilhelmsson, Ola
    Department of Materials Chemistry, The Ångström Laboratory, Uppsala University, Sweden.
    Isberg, Peter
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Birch, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Persson, Per O. Å.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Jansson, Ulf
    Department of Materials Chemistry, The Ångström Laboratory, Uppsala University, Sweden.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Structural, electrical, and mechanical properties of nc-TiC/a-SiC nanocomposite thin films2005In: Journal of Vacuum Science & Technology B, ISSN 1071-1023, E-ISSN 1520-8567, Vol. 23, no 6, 2486-2495 p.Article in journal (Refereed)
    Abstract [en]

    We have synthesized Ti–Si–C nanocomposite thin films by dc magnetron sputtering from a Ti3SiC2 compound target in an Ar discharge on Si(100), Al2O3(0001), and Al substrates at temperatures from room temperature to 300  °C. Electron microscopy, x-ray diffraction, and x-ray photoelectron spectroscopy showed that the films consisted of nanocrystalline (nc-) TiC and amorphous (a-) SiC, with the possible presence of a small amount of noncarbidic C. The growth mode was columnar, yielding a nodular film-surface morphology. Mechanically, the films exhibited a remarkable ductile behavior. Their nanoindentation hardness and E-modulus values were 20 and 290  GPa, respectively. The electrical resistivity was 330  µ  cm for optimal Ar pressure (4  mTorr) and substrate temperature (300  °C). The resulting nc-TiC/a-SiC films performed well as electrical contact material. These films' electrical-contact resistance against Ag was remarkably low, 6  µ at a contact force of 800  N compared to 3.2  µ for Ag against Ag. The chemical stability of the nc-TiC/a-SiC films was excellent, as shown by a Battelle flowing mixed corrosive-gas test, with no N, Cl, or S contaminants entering the bulk of the films.

  • 18.
    Eklund, Per
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Epitaxial TiC/SiC multilayers2007In: Physica status solidi (RRL): rapid research letters, ISSN 1862-6254, Vol. 1, no 3, 113-115 p.Article in journal (Refereed)
    Abstract [en]

    Epitaxial TiC/SiC multilayers were grown by magnetron sputtering at a substrate temperature of 550 °C, where SiC is normally amorphous. The epitaxial TiC template induced growth of cubic SiC up to a thickness of ~2 nm. Thicker SiC layers result in a direct transition to growth of the metastable amorphous SiC followed by renucleation of nanocrystalline TiC layers

  • 19.
    Eklund, Per
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Joelsson, Torbjörn
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Ljungcrantz, Henrik
    Impact Coatings AB, Linköping, Sweden.
    Wilhelmsson, Ola
    Department of Materials Chemistry, The Ångström Laboratory, Uppsala University, Uppsala, Sweden.
    Czigany, Zsolt
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Microstructure and electrical properties of Ti-Si-C-Ag nanocomposite thin films2007In: Surface and Coatings Technology, ISSN 0257-8972, Vol. 201, no 14, 6465-6469 p.Article in journal (Refereed)
    Abstract [en]

    Ti–Si–C–Ag nanocomposite coatings consisting of nanocrystalline TiC in an amorphous Si matrix with segregated Ag were deposited by dual magnetron sputtering from Ti3SiC2 and Ag targets. As evidenced by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy, for Ag contents below 10 at.%, the Ag forms 10 nm large crystallites that are homogeneously distributed in the films. For higher Ag contents, coalescence during growth results in the formation of >  100 nm Ag islands on the film surface. The electrical resistivity of the coatings was measured in a four-point-probe setup, and ranged from 340 μΩcm (for Ti–Si–C coatings without Ag) to 40 μΩcm (for high Ag content).

  • 20.
    Eklund, Per
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Murugaiah, Anand
    Department of Materials Science and Engineering, Drexel University, Philadelphia, USA.
    Emmerlich, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Czigany, Zsolt
    Research Institute for Technical Physics and Materials Science, Hungarian Academy of Sciences, Budapest, Hungary.
    Frodelius, Jenny
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Barsoum, Michel W.
    Department of Materials Science and Engineering, Drexel University, Philadelphia, USA.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Homoepitaxial growth of Ti-Si-C MAX-phase thin films on bulk Ti3SiC2 substrates2007In: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 304, no 1, 264-269 p.Article in journal (Refereed)
    Abstract [en]

    Ti3SiC2 films were grown on polycrystalline Ti3SiC2 bulk substrates using DC magnetron sputtering. The crystallographic orientation of the film grains is shown to be determined by the respective substrate-grain orientation through homoepitaxial MAX-phase growth. For a film composition close to Ti:Si:C=3:1:2, the films predominantly consist of MAX phases, both Ti3SiC2 and the metastable Ti4SiC3. Lower Si content resulted in growth of TiC with Ti3SiC2 as a minority phase. Thus, MAX-phase heterostructures with preferred crystallographic relationships can also be realized.

  • 21.
    Eklund, Per
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Palmquist, Jens-Petter
    Kanthal AB.
    Höwing, Jonas
    Institute of Energy Technology, Kjeller, Norway.
    Trinh, David
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    El-Raghy, Tamer
    3-ONE-2, USA.
    Högberg, Hans
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Hultman, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Ta4AlC3: Phase determination, polymorphism and deformation2007In: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 55, no 14, 4723-4729 p.Article in journal (Refereed)
    Abstract [en]

    Ta4AlC3, a new member of the Mn+1AXn-phase family, has been synthesized and characterized (n = 1-3, M = early transition metal, A = A-group element, and X = C and/or N). Phase determination by Rietveld refinement of synchrotron X-ray diffraction data shows that Ta4AlC3 belongs to the P63/mmc space group with a and c lattice parameters of 3.10884 ± 0.00004 Å and 24.0776 ± 0.0004 Å, respectively. This is shown to be the α-polymorph of Ta4AlC3, with the same structure as Ti4AlN3. Lattice imaging by high-resolution transmission electron microscopy demonstrates the characteristic MAX-phase stacking of α-Ta4AlC3. Three modes of mechanical deformation of α-Ta4AlC3 are observed: lattice bending, kinking and delamination. © 2007.

  • 22.
    Eklund, Per
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Palmquist, Jens-Petter
    Uppsala universitet.
    Wilhelmsson, Ola
    Uppsala universitet.
    Jansson, Ulf
    Uppsala universitet.
    Emmerlich, Jens
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Högberg, Hans
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Hultman, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Comment on "Pulsed laser deposition and properties of Mn+1AXx phase formulated Ti3SiC2 thin films"2004In: Tribology letters, ISSN 1023-8883, E-ISSN 1573-2711, Vol. 17, no 4, 977-978 p.Article in journal (Other academic)
    Abstract [en]

    A recent paper by Hu et al. claimed synthesis of the MAX-phase Ti3SiC2at 100-300 °C using pulsed laser deposition. In this comment, we find that the evidence presented by Hu et al. is insufficient to show Ti3SiC2 formation. In fact, there is a simpler interpretation of their results from X-ray diffraction and transmission electron microscopy, namely that the material produced is a cubic TiC-based compound.

  • 23.
    Eklund, Per
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Palmquist, JP
    Department of Materials Chemistry, The Angström Laboratory, Uppsala University, Uppsala, Swede.
    Wilhelmsson, O
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Jansson, U
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Emmerlich, Jens
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Högberg, Hans
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Hultman, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Comment on "Pulsed laser deposition and properties of M(n+1)AX(x) phase formulated Ti3SiC2 thin films''2004In: Tribology letters, ISSN 1023-8883, E-ISSN 1573-2711, Vol. 17, no 4, 977-978 p.977-978 p.Article in journal (Other academic)
    Abstract [en]

    A recent paper by Hu et al. claimed synthesis of the MAX-phase Ti3SiC2 at 100 - 300 degreesC using pulsed laser deposition. In this comment, we find that the evidence presented by Hu et al. is insufficient to show Ti3SiC2 formation. In fact, there is a simpler interpretation of their results from X-ray diffraction and transmission electron microscopy, namely that the material produced is a cubic TiC-based compound.

  • 24.
    Eklund, Per
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Virojanadara, Chariya
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Emmerlich, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Johansson, Leif
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Photoemission studies of Ti3SiC2 and nanocrystalline-TiC/amorphous-SiC nanocomposite thin films2006In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 74, no 4, 045417- p.Article in journal (Refereed)
    Abstract [en]

    Photoemissionstudies using synchrotron radiation have been performed on epitaxial Ti3SiC2(0001)and compound nanocrystalline (nc-)TiC/amorphous (a-)SiC thin films deposited by magnetronsputtering. As-introduced samples were found to be covered by surfaceoxides, SiOx and TiOx. These oxides could be removed byin-situ annealing to ~1000  °C. For as-annealed Ti3SiC2(0001), surface Si wasobserved and interpreted as originating from decomposition of Ti3SiC2 throughSi out-diffusion. For nc-TiC/a-SiC annealed in situ to ~1000  °C, thesurface instead exhibited a dominant contribution from graphitic carbon, alsowith the presence of Si, due to C and Siout-diffusion from the a-SiC compound or from grain boundaries.

  • 25.
    Emmerlich, Jens
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Rittrich, Dirk
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Electrical resistivity of Tin+1ACn (A = Si, Ge, Sn, n = 1–3) thin films2007In: Journal of Materials Research, ISSN 0884-2914, E-ISSN 2044-5326, Vol. 22, no 8, 2279-2287 p.Article in journal (Refereed)
    Abstract [en]

    We have investigated the electrical resistivity of (0001)-oriented Tin+1ACn (A = Si, Ge, Sn, n = 1–3) thin films deposited by magnetron sputtering onto Al2O3(0001) substrates at temperatures ranging from 500 to 950 °C. Four-point-probe measurements show that all films are good conductors with resistivity values of ∼21–51 μΩ cm for Ti–Si–C films, ∼15–50 μΩ cm for Ti–Ge–C films, and ∼46 μΩ cm for Ti2SnC. We find a general trend of decreasing resistivity with decreasing n for the Ti–Si–C and Ti–Ge–C systems due to the increased metallicity obtained with increasing density of A-element layers. We also show that crystalline quality and competitive growth of impurity phases affect the measured resistivity values. The effect of a given impurity phase largely depends on its location in the sample. Specifically, a TiCx layer in the center of the film constricts the current flow and results in an increased measured resistivity value. However, TiCx transition or seed layers at the substrate–film interface as well as surface segregation of Ge and Ti5Ge3Cx (for Ti–Ge–C) have only little effect on the measured resistivity values. For the Ti–Sn–C system, the resistivity is mainly influenced by the segregation of metallic Sn, yielding a wide spread in the measured values ranging from 20–46 μΩ cm, in the order of increased film purity.

  • 26.
    Emmerlich, Jens
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Gassner, Gert
    Department of Physical Metallurgy and Materials Testing, University of Leoben, Austria.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Micro and macroscale tribological behavior of epitaxial Ti3SiC2 thin films2008In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 264, no 11-12, 914-919 p.Article in journal (Refereed)
    Abstract [en]

    Ti3SiC2(0 0 0 1) thin films prepared by magnetron sputtering were investigated for their response to tribomechanical strain induced during ball-on-disk experiments with 6 mm alumina balls and scratch tests with a 1 μm cono-spherical diamond tip. Normal loads of 100 μN to 0.24 N were applied resulting in a friction coefficient of 0.1 for the low loads. With higher applied normal loads, the friction coefficient increased up to 0.8. Analysis of the wear tracks using atomic force microscopy, scanning electron microscopy, and Raman spectroscopy revealed excessive debris resulting in third-body abrasion and fast wear. The formation of the debris can be explained by the generation of subsurface delamination cracks on basal planes. Subsequent kink formation obstructs the ball movement which results in the removal of the kinked film parts.

  • 27.
    Emmerlich, Jens
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Sasvári, Szilvia
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Persson, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Palmquist, Jens-Petter
    Department of Material Chemistry, Uppsala University, The Ångström Laboratory, Uppsala, Sweden .
    Jansson, Ulf
    Department of Material Chemistry, Uppsala University, The Ångström Laboratory, Uppsala, Sweden .
    Molina-Aldareguia, Jon M.
    CEIT (Centro de Estudios e Investigaciones Técnicas e Gipuzkoa), Spain .
    Czigány, Zsolt
    Research Institute for Technical Physics and Materials Science, Hungary .
    Growth of Ti3SiC2 thin films by elemental target magnetron sputtering2004In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 96, no 9, 4817-4826 p.Article in journal (Refereed)
    Abstract [en]

    Epitaxial Ti3SiC2(0001) thin films have been deposited by dc magnetron sputtering from three elemental targets of Ti, C, and Si onto MgO(111) and Al2O3(0001) substrates at temperatures of 800–900 °C. This process allows composition control to synthesize Mn+1AXn (MAX) phases (M: early transition metal; A: A-group element; X: C and∕or N; n=1–3) including Ti4SiC3. Depositions on MgO(100) substrates yielding the Ti–Si–C MAX phases with (105), as the preferred orientation. Samples grown at different substrate temperatures, studied by means of transmission electron microscopy and x-ray diffraction investigations, revealed the constraints of Ti3SiC2 nucleation due to kinetic limitations at substrate temperatures below 700 °C. Instead, there is a competitive TiCx growth with Si segregation to form twin boundaries or Si substitutional incorporation in TiCx. Physical properties of the as-deposited single-crystal Ti3SiC2 films were determined. A low resistivity of 25 μΩ cm was measured. The Young’s modulus, ascertained by nanoindentation, yielded a value of 343–370 GPa. For the mechanical deformation response of the material, probing with cube corner and Berkovich indenters showed an initial high hardness of almost 30 GPa. With increased maximum indentation loads, the hardness was observed to decrease toward bulk values as the characteristic kink formation sets in with dislocation ordering and delamination at basal planes.

  • 28.
    Emmerlich, Jens
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Music, Denis
    Materials Chemistry, RWTH Aachen University, Germany.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Wilhelmsson, Ola
    Department of Materials Chemistry, Uppsala University, Uppsala, Sweden.
    Jansson, Ulf
    Department of Materials Chemistry, Uppsala University, Uppsala, Sweden.
    Schneider, Jochen M.
    Materials Chemistry, RWTH Aachen University, Germany.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Thermal stability of Ti3SiC2 thin films2007In: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 55, no 4, 1479-1488 p.Article in journal (Refereed)
    Abstract [en]

    The thermal stability of Ti3SiC2(0 0 0 1) thin films is studied by in situ X-ray diffraction analysis during vacuum furnace annealing in combination with X-ray photoelectron spectroscopy, transmission electron microscopy and scanning transmission electron microscopy with energy dispersive X-ray analysis. The films are found to be stable during annealing at temperatures up to ∼1000 °C for 25 h. Annealing at 1100–1200 °C results in the rapid decomposition of Ti3SiC2 by Si out-diffusion along the basal planes via domain boundaries to the free surface with subsequent evaporation. As a consequence, the material shrinks by the relaxation of the Ti3C2 slabs and, it is proposed, by an in-diffusion of O into the empty Si-mirror planes. The phase transformation process is followed by the detwinning of the as-relaxed Ti3C2 slabs into (1 1 1)-oriented TiC0.67 layers, which begin recrystallizing at 1300 °C. Ab initio calculations are provided supporting the presented decomposition mechanisms.

  • 29.
    Frodelius, Jenny
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Beckers, Manfred
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Persson, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Sputter deposition from a Ti2AlC target: Process characterization and conditions for growth of Ti2AlC2010In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 518, no 6, 1621-1626 p.Article in journal (Refereed)
    Abstract [en]

    Sputter deposition from a Ti2AlC target was found to yield Ti-Al-C films with a composition that deviates from the target composition of 2:1:1. For increasing substrate temperature from ambient to 1000 degrees C, the Al content decreased from 22 at.% to 5 at.%, due to re-evaporation. The C content in as-deposited films was equal to or higher than the Ti content. Mass spectrometry of the plasma revealed that the Ti and Al species were essentially thermalized, while a large fraction of C with energies andgt;4 eV was detected. Co-sputtering with Ti yielded a film stoichiometry of 2:0.8:0.9 for Ti:Al:C, which enabled growth of Ti2AlC. These results indicate that an additional Ti flux balances the excess C and therefore provides for more stoichiometric Ti2AlC synthesis conditions.

  • 30.
    Frodelius, Jenny
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Sonestedt, Marie
    Chalmers University of Technology, Microscopy and Microanalysis, Department of Applied Physics, Göteborg, Sweden.
    Björklund, Stefan
    University West, Department of Technology, Mathematics and Computer Science, Trollhättan, Sweden.
    Palmquist, Jens-Petter
    Kanthal AB, Hallstahammar, Sweden.
    Stiller, Krystyna
    Chalmers University of Technology, Microscopy and Microanalysis, Department of Applied Physics, Göteborg, Sweden.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Ti2AlC coatings deposited by High Velocity Oxy-Fuel spraying2008In: Surface and Coatings Technology, ISSN 0257-8972, Vol. 202, no 24, 5976-5981 p.Article in journal (Refereed)
    Abstract [en]

    High Velocity Oxy-Fuel has been utilized to spray coatings from Ti2AlC (MAXTHAL 211®) powders. X-ray diffraction showed that the coatings consist predominantly of Ti2AlC with inclusions of the phases Ti3AlC2, TiC, and Al–Ti alloys. The fraction of Ti2AlC in coatings sprayed with a powder size of 38 μm was found to increase with decreasing power of the spraying flame as controlled by the total gas flow of H2 and O2. A more coarse powder (56 μm) is less sensitive to the total gas flow and retains higher volume fraction of MAX-phase in the coatings, however, at the expense of increasing porosity. X-ray pole figure measurements showed a preferred crystal orientation in the coatings with the Ti2AlC (000l) planes aligned to the substrate surface. Bending tests show a good adhesion to stainless steel substrates and indentation yields a hardness of 3–5 GPa for the coatings sprayed with a powder size of 38 μm.

  • 31.
    Furlan, Andrej
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Gueorguiev, Gueorgui Kostov
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Czigány, Zsolt
    Research Institute for Technical Physics and Materials Science, P.O. Box 49, Budapest, H-1525, Hungary.
    Darakchieva, Vanya
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Braun, Slawomir
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Correia, Rosario
    I3N and Physics Department, University of Aveiro, 3810-193 Aveiro, Portugal.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Structure and properties of phosphorus-carbide thin solid films2013In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 548, no 2, 247-254 p.Article in journal (Refereed)
    Abstract [en]

    Phosphorus-carbide (CPx) thin films have been deposited by unbalanced reactive magnetron sputtering and investigated by TEM, XPS, SEM, ERDA, Raman scattering spectroscopy, nanoindentation testing, and four-point electrical probe techniques. As-deposited films with x=0.1 are electron amorphous with elements of FL structure and high mechanical resiliency with hardness of 34.4 GPa and elastic recovery of 72%. The electrical resistivity of the films are in the range 0.4-1.7 Ωcm for CP0.027, 1.4-22.9 Ωcm for CP0.1, and lower than the minimal value the four-point probe is able to detect for CPx with x≥0.2.

  • 32.
    Furlan, Andrej
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Gueorguiev, Gueorgui Kostov
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Czigány, Zsolt
    Research Institute for Technical Physics and Materials Science, P.O. Box 49, Budapest, Hungary.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Braun, Slawomir
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry . Linköping University, The Institute of Technology.
    Stafström, Sven
    Linköping University, Department of Physics, Chemistry and Biology, Computational Physics . Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Synthesis of phosphorus-carbide thin films by magnetron sputtering2008In: physica status solidi (RRL) - Rapid Research Letters, ISSN 1862-6254, Vol. 2, no 4, 191-193 p.Article in journal (Refereed)
    Abstract [en]

    Phosphorus-carbide, CPx (0.025≤x≤0.1) thin films have beensynthesized by magnetron sputtering from pressed graphite-phosphorustargets. The films were characterized by X-ray photoelectron spectroscopy,transmission electron microscopy and diffraction, andnanoindentation. CP0.02 exhibits C-P bonding in an amorphous structure with elements of curved grapheneplanes, yielding a material with unique short range order. These features are consistent with what has been predicted by our results of theoreticallymodeled synthetic growth of CPx. The films are mechanicallyresilient with hardness up to 24 GPa and elastic recovery upto 72%.

  • 33.
    Furlan, Andrej
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Gueorguiev, Gueorgui Kostov
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Stafström, Sven
    Linköping University, Department of Physics, Chemistry and Biology, Computational Physics . Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Fullerene–like CPx: A first–principles study of the relative stability of precursors and defect energetics during synthetic growth2006In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 515, no 3, 1028-1032 p.Article in journal (Refereed)
    Abstract [en]

    Inherently nanostructured CPx compounds were studied by first-principles calculations. Geometry optimizations and cohesive energy comparisons show stability for C3P, C2P, C3P2, CP, and P4 (P2) species in isolated form as well as incorporated in graphene layers. The energy cost for structural defects, arising from the substitution of C for P and intercalation of P atoms in graphene, was also evaluated. We find a larger curvature of the graphene sheets and a higher density of cross-linkage sites in comparison to fullerene-like (FL) CNx, which is explained by differences in the bonding between P and N. Thus, the computational results extend the scope of fullerene-like thin film materials with FL-CPx and provide insights for its structural properties.

  • 34.
    Goyenola, Cecilia
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Lai, Chung-Chuan
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Näslund, Lars-Åke
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Rosén, Johanna
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Gueorguiev, Gueorgui Kostov
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Theoretical prediction and synthesis of CSxFy thin films2016In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 120, no 17, 9527-9534 p.Article in journal (Refereed)
    Abstract [en]

    A new carbon-based compound: CSxFy was addressed by density functional theory calculations and synthesized by reactive magnetron sputtering. Geometry optimizations and energy calculations were performed on graphene-like model systems containing sulfur and fluorine atoms. It is shown that [S+F] concentrations in the range of 0−10 at.%, structural ordered characteristics similar to graphene pieces containing ring defects are energetically feasible. The modeling predicts that CSxFy thin films with graphite and fullerene-like characteristics may be obtained for the mentioned concentration range. Accordingly, thin films were synthesized from a graphite solid target and sulfur hexafluoride as reactive gas. In agreement with the theoretical prediction, transmission electron microscopy characterization and selected area electron diffraction confirmed the presence of small ordered clusters with graphitic features in a sample containing 0.4 at.% of S and 3.4 at.% of F.

  • 35.
    Gueorguiev, Gueorgui Kostov
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Furlan, Andrej
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Stafström, Sven
    Linköping University, Department of Physics, Chemistry and Biology, Computational Physics . Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    First–principles calculations on the structural evolution of solid fullerene–like CPx2006In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 426, no 4-6, 374-379 p.Article in journal (Refereed)
    Abstract [en]

    The formation and structural evolution of fullerene-like (FL) carbon phosphide (CPx) during synthetic growth were studied by first-principles calculations. Geometry optimizations and comparison between the cohesive energies suggest stability for solid FL-CPx compounds. In comparison with fullerene-like carbon nitride, higher curvature of the graphene sheets and higher density of cross-linkages between them is predicted and explained by the different electronic properties of P and N. Cage-like and onion-like structures, both containing tetragons, are found to be typical for fullerene-like CPx. Segregation of P is predicted at fractions exceeding ~20 at.%.

  • 36.
    Gunnarsson Sarius, Niklas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Lauridsen, Jonas
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Lewin, E.
    Department of Materials Chemistry, The Ångström Laboratory, Uppsala University, Sweden.
    Jansson, U.
    Department of Materials Chemistry, The Ångström Laboratory, Uppsala University, Sweden.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Öberg, Å.
    ABB Corporate Research, Forskargränd 7, SE-721 78 Västerås, Sweden.
    Leisner, P.
    SP Technical Research Institute of Sweden, Box 857, 501 15 Borås, Sweden/School of Engineering Jönköping University, Sweden.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Contact resistance of Ti-Si-C-Ag and Ti-Si-C-Ag-Pd nanocomposite coatings2012In: Journal of Electronic Materials, ISSN 0361-5235, E-ISSN 1543-186X, Vol. 41, no 3, 560-567 p.Article in journal (Refereed)
    Abstract [en]

    Ti-Si-C-Ag-Pd and Ti-Si-C-Ag nanocomposite coatings were deposited by magnetronsputtering on Cu substrates with an electroplated Ni layer. Analytical electronmicroscopy and x-ray diffraction show that the nanocomposites consist of TiC,Ag:Pd, and amorphous SiC. The contact resistance of these coatings against aspherical Au-Co surface was measured for applied contact force up 0 to 5 N. Ti-Si-CAg-Pd coatings with a Ag:Pd strike coating has ~10 times lower contact resistance atcontact forces below 1 N (~10 mΩ at ~0.1N), and ~2 times lower for contact forcesaround 5 N (<1 mΩ at 5 N), compared to the Ti-Si-C-Ag coating.

  • 37.
    Gunnarsson Sarius, Niklas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Lauridsen, Jonas
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Lewin, E.
    Department of Materials Chemistry, The Ångström Laboratory, Uppsala University, Sweden.
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Öberg, Å.
    ABB Corporate Research, Forskargränd 7, SE-721 78 Västerås, Sweden.
    Ljungcrantz, H.
    Impact Coatings AB, Westmansgatan 29, SE-582 16 Linköping, Sweden.
    Leisner, P.
    SP Technical Research Institute of Sweden, Box 857, SE-501 15 Borås, Sweden/School of Engineering Jönköping University, Box 1026, SE- 551 11 Jönköping, Sweden.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Ni and Ti diffusion barrier layers between Ti-Si-C-Ag nanocomposite coatings and Cu-based substrates2012In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 206, no 8-9, 2558-2565 p.Article in journal (Refereed)
    Abstract [en]

    Sputtered Ni and Ti layers were investigated as substitutes for electroplated Ni as adiffusion barrier between Ti-Si-C and Ti-Si-C-Ag nanocomposite coatings and Cu orCuSn substrates. Samples were subjected to thermal annealing studies by exposure to400 ºC during 11 h. Dense diffusion barrier and coating hindered Cu from diffusing tothe surface. This condition was achieved for electroplated Ni in combination withmagnetron-sputtered Ti-Si-C and Ti-Si-C-Ag layers deposited at 230 ºC and 300 ºC,and sputtered Ti or Ni layers in combination with Ti-Si-C-Ag deposited at 300 ºC.

  • 38.
    Henry, Anne
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Chubarov, Mikhail
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering. Grenoble INP, France.
    Czigany, Zsolt
    Hungarian Academic Science, Hungary.
    Garbrecht, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Early stages of growth and crystal structure evolution of boron nitride thin films2016In: Japanese Journal of Applied Physics, ISSN 0021-4922, E-ISSN 1347-4065, Vol. 55, no 5, 05FD06- p.Article in journal (Refereed)
    Abstract [en]

    A study of the nucleation and crystal structure evolution at the early stages of the growth of sp(2)-BN thin films on 6H-SiC and alpha-Al2O3 substrates is presented. The growth is performed at low pressure and high temperature in a hot wall CVD reactor, using ammonia and triethylboron as precursors, and H-2 as carrier gas. From high-resolution transmission electron microscopy and X-ray thin film diffraction measurements we observe that polytype pure rhombohedral BN (r-BN) is obtained on 6H-SiC substrates. On alpha-Al2O3 an AlN buffer obtained by nitridation is needed to promote the growth of hexagonal BN (h-BN) to a thickness of around 4 nm followed by a transition to r-BN growth. In addition, when r-BN is obtained, triangular features show up in plan-view scanning electron microscopy which are not seen on thin h-BN layers. The formation of BN after already one minute of growth is confirmed by X-ray photoelectron spectroscopy. (C) 2016 The Japan Society of Applied Physics

  • 39.
    Hugosson, H.W.
    et al.
    Applied Materials Physics, Department of Materials Science, Royal Institute of Technology, S-100 44 Stockholm, Sweden, Condensed Matter Theory Group, Department of Physics, Uppsala University, S-751 21 Uppsala, Sweden.
    Högberg, Hans
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Algren, M.
    Sandvik Coromant AB, Stockholm, Sweden.
    Rodmar, M.
    Sandvik Coromant AB, Stockholm, Sweden.
    Selinder, T.I.
    Sandvik Coromant AB, Stockholm, Sweden.
    Theory of the effects of substitutions on the phase stabilities of Ti1-xAlxN2003In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 93, no 8, 4505-4511 p.Article in journal (Refereed)
    Abstract [en]

    The theory of the effects of substitutions on the phase stabilities of Ti1-xAlxN was discussed. The substitution that increased the thermal stability of the NaCl structure of Ti1-xAlxN at high Al content was elaborated. Some possible avenues for such stabilization were presented and the substitution with nonmetal C and Si, and metal V, Cr and Mn was found to be most promising.

  • 40.
    Hänninen, Tuomas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Schmidt, Susann
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Jensen, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Silicon oxynitride films deposited by reactive high power impulse magnetron sputtering using nitrous oxide as a single-source precursor2015In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 33, no 5, 05E121- p.Article in journal (Refereed)
    Abstract [en]

    Silicon oxynitride thin films were synthesized by reactive high power impulse magnetron sputtering of silicon in argon/nitrous oxide plasmas. Nitrous oxide was employed as a single-source precursor supplying oxygen and nitrogen for the film growth. The films were characterized by elastic recoil detection analysis, x-ray photoelectron spectroscopy, x-ray diffraction, x-ray reflectivity, scanning electron microscopy, and spectroscopic ellipsometry. Results show that the films are silicon rich, amorphous, and exhibit a random chemical bonding structure. The optical properties with the refractive index and the extinction coefficient correlate with the film elemental composition, showing decreasing values with increasing film oxygen and nitrogen content. The total percentage of oxygen and nitrogen in the films is controlled by adjusting the gas flow ratio in the deposition processes. Furthermore, it is shown that the film oxygen-to-nitrogen ratio can be tailored by the high power impulse magnetron sputtering-specific parameters pulse frequency and energy per pulse. (C) 2015 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.

  • 41.
    Hänninen, Tuomas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Schmidt, Susann
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Wissting, Jonas
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Jensen, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Stoichiometric silicon oxynitride thin films reactively sputtered in Ar/N2O plasmas by HiPIMS2016In: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 49, no 13, 135309Article in journal (Refereed)
    Abstract [en]

    Silicon oxynitride (SiOxNy, x = 0.2 − 1.3, y = 0.2 − 0.7) thin films were synthesized by reactive high power impulse magnetron sputtering from a pure silicon target in Ar/N2O atmospheres. It is found that the composition of the material can be controlled by the reactive gas flow and the average target power. X-ray photoelectron spectroscopy (XPS) shows that high average powers result in more silicon-rich films, while lower target powers yield silicon-oxide-like material due to more pronounced target poisoning. The amount of nitrogen in the films can be controlled by the percentage of nitrous oxide in the working gas. The nitrogen content remains at a constant level while the target is operated in the transition region between metallic and poisoned target surface conditions. The extent of target poisoning is gauged by the changes in peak target current under the different deposition conditions. XPS also shows that varying concentrations and ratios of oxygen and nitrogen in the films result in film chemical bonding structures ranging from silicon-rich to stoichiometric silicon oxynitrides having no observable Si−Si bond contributions. Spectroscopic ellipsometry shows that the film optical properties depend on the amount and ratio of oxygen and nitrogen in the compound, with film refractive indices measured at 633 nm ranging between those of SiO2 and Si3N4.

  • 42.
    Högberg, Hans
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Birch, Jens
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Johansson, MP
    Hultman, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Jansson, U
    Uppsala Univ, Dept Inorgan Chem, Angstrom Lab, SE-75121 Uppsala, Sweden Linkoping Univ, Dept Phys, Thin Film Phys Div, SE-58183 Linkoping, Sweden.
    Deposition of epitaxial transition metal carbide films and superlattices by simultaneous direct current metal magnetron sputtering and C-60 evaporation2001In: Journal of Materials Research, ISSN 0884-2914, E-ISSN 2044-5326, Vol. 16, no 3, 633-643 p.Article in journal (Refereed)
    Abstract [en]

    Thin epitaxial TiC and VC films and superlattices have been deposited on MgO(001) by simultaneous sputtering of the metals and evaporation of C-60. It was found that epitaxial growth conditions for TiC could be maintained down to a temperature of 100 degreesC, while the epitaxial growth of VC required 200 degreesC, Epitaxial VC films were completely relaxed at all growth temperatures, while a change from a relaxed to a strained growth behavior was observed for TiC films. The structural quality of the TiC films was better than for the VC films. A general observation was that a plasma-assisted deposition process yields films with a higher quality and allows epitaxial growth at lower temperatures than for a pure coevaporation process.

  • 43.
    Högberg, Hans
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Eklund, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Emmerlich, Jens
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Birch, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Epitaxial Ti2GeC, Ti3GeC2, and Ti4GeC3 MAX-phase thin films grown by magnetron sputtering2005In: Journal of Materials Research, ISSN 0884-2914, E-ISSN 2044-5326, Vol. 20, no 4, 779-782 p.Article in journal (Refereed)
    Abstract [en]

    We have grown single-crystal thin films of Ti2GeC and Ti3GeC2 and a new phase Ti4GeC3, as well as two new intergrown MAX-structures, Ti5Ge2C3 and Ti7Ge2C5. Epitaxial films were grown on Al2O3(0001) substrates at 1000 °C using direct current magnetron sputtering. X-ray diffraction shows that Ti–Ge–C MAX-phases require higher deposition temperatures in a narrower window than their Ti–Si–C correspondences do, while there are similarities in phase distribution. Nanoindentation reveals a Young’s modulus of 300 GPa, lower than that of Ti3SiC2. Four-point probe measurements yield resistivity values of 50–200 μΩcm. The lowest value is obtained for phase-pure Ti3GeC2(0001) films.

  • 44.
    Högberg, Hans
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Emmerlich, Jens
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Eklund, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Wilhelmsson, Ola
    Palmquist, Jens-Petter
    Jansson, Ulf
    Hultman, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Growth and characterization of epitaxial MAX-phase thin films from the Tin+1(Si,Ge,Sn)Cn systems2006In: 11th International Ceramics Congress, CIMTEC,2006, Zürich: TransTech Publications , 2006, 2648- p.Conference paper (Refereed)
    Abstract [en]

      

  • 45.
    Högberg, Hans
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Emmerlich, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Joelsson, Torbjörn
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Molina-Aldareguia, Jon M.
    Department of Materials, CEIT, Spain.
    Palmquist, Jens-Petter
    Department of Materials Chemistry, The Ångström Laboratory, Uppsala University, Uppsala, Sweden.
    Wilhelmsson, Ola
    Department of Materials Chemistry, The Ångström Laboratory, Uppsala University, Uppsala, Sweden.
    Jansson, Ulf
    Department of Materials Chemistry, The Ångström Laboratory, Uppsala University, Uppsala, Sweden.
    Growth and characterization of MAX-phase thin films2005In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 193, no 1-3, 6-10 p.Article in journal (Refereed)
    Abstract [en]

    We report that magnetron sputtering can be applied to synthesize MAX-phase films of several systems including Ti–Si–C, Ti–Ge–C, Ti–Al–C, and Ti–Al–N. In particular, epitaxial films of the known phases Ti3SiC2, Ti3GeC2, Ti2GeC, Ti3AlC2, Ti2AlC, and Ti2AlN as well as the newly discovered thin film phases Ti4SiC3, Ti4GeC3 and intergrown structures can be deposited at 900–1000 °C on Al2O3(0001) and MgO(111) pre-seeded with TiC or Ti(Al)N. From XTEM and AFM we suggest a growth and nucleation model where MAX-phase nucleation is initiated at surface steps or facets on the seed layer and followed by lateral growth. Differences between the growth behavior of the systems with respect to phase distribution and phase stabilities are discussed. Characterization of mechanical properties for Tin+1Si–Cn films with nanoindentation show decreased hardness from about 25 to 15 GPa upon penetration of the basal planes with characteristic large plastic deformation with pile up dependent on the choice of MAX material. This is explained by cohesive delamination of the basal planes and kink band formation, in agreement with the observations made for bulk material. Measurements of the electrical resistivity for Ti–Si–C and Ti–Al–N films with four-point probe technique show values of 30 and 39 μΩ cm, respectively, comparable to bulk materials.

  • 46.
    Högberg, Hans
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Tengdelius, Lina
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Samuelsson, Mattias
    Impact Coatings AB, Linköping, Sweden .
    Eriksson, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Broitman, Esteban
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Arts and Sciences.
    Jensen, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Reactive sputtering of delta-ZrH2 thin films by high power impulse magnetron sputtering and direct current magnetron sputtering2014In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 32, no 4, 041510- p.Article in journal (Refereed)
    Abstract [en]

    Reactive sputtering by high power impulse magnetron sputtering (HiPIMS) and direct current magnetron sputtering (DCMS) of a Zr target in Ar/H-2 plasmas was employed to deposit Zr-H films on Si(100) substrates, and with H content up to 61 at.% and O contents typically below 0.2 at.% as determined by elastic recoil detection analysis. X-ray photoelectron spectroscopy reveals a chemical shift of similar to 0.7 eV to higher binding energies for the Zr-H films compared to pure Zr films, consistent with a charge transfer from Zr to H in a zirconium hydride. X-ray diffraction shows that the films are single-phase delta-ZrH2 (CaF2 type structure) at H content greater thansimilar to 55 at.% and pole figure measurements give a 111 preferred orientation for these films. Scanning electron microscopy cross-section images show a glasslike microstructure for the HiPIMS films, while the DCMS films are columnar. Nanoindentation yield hardness values of 5.5-7 GPa for the delta-ZrH2 films that is slightly harder than the similar to 5 GPa determined for Zr films and with coefficients of friction in the range of 0.12-0.18 to compare with the range of 0.4-0.6 obtained for Zr films. Wear resistance testing show that phase-pure delta-ZrH2 films deposited by HiPIMS exhibit up to 50 times lower wear rate compared to those containing a secondary Zr phase. Four-point probe measurements give resistivity values in the range of similar to 100-120 mu Omega cm for the delta-ZrH2 films, which is slightly higher compared to Zr films with values in the range 70-80 mu Omega cm.

  • 47.
    Högberg, Hans
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Tengdelius, Lina
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Samuelsson, Mattias
    Impact Coatings AB, Linkoping, Sweden .
    Jensen, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    beta-Ta and alpha-Cr thin films deposited by high power impulse magnetron sputtering and direct current magnetron sputtering in hydrogen containing plasmas2014In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 439, 3-8 p.Article in journal (Refereed)
    Abstract [en]

    Thin films of beta-Ta and alpha-Cr were deposited on Si(1 0 0) and 1000 angstrom SiO2/Si(1 0 0), by high power impulse magnetron sputtering (HiPIMS) and direct current magnetron sputtering (dcMS) in hydrogen-containing plasmas. The films were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction, scanning electron microscopy, elastic recoil detection analysis, and four-point probe measurements. The results showed that 001-oriented beta-Ta films containing up to similar to 8 at% hydrogen were obtained with HiPIMS, albeit with no chemical shift evident in XPS. The 110 oriented alpha-Cr films display a hydrogen content less than the detection limit of 1 at%, but H-2 favors the growth of high-purity films for both metals. The beta-Ta films deposited with dcMS are columnar, which seems independent of H-2 presence in the plasma, while the films grown by HIPIMS are more fine-grained. The latter type of microstructure was present for the alpha-Cr films and found to be independent on choice of technique or hydrogen in the plasma. The beta-Ta films show a resistivity of similar to 140-180 mu Omega cm, while alpha-Cr films exhibit values around 30 mu Omega cm; the lowest values obtained for films deposited by HiPIMS and with hydrogen in the plasma for both metals.

  • 48.
    Isberg, Peter
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Eklund, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Emmerlich, Jens
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Hultman, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Högberg, Hans
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Ljungcrantz, Henrik
    Impact Coatings AB.
    Amorphous and nanocomposite MAX compounds for wear protective coatings on components and tools as well as electrical contacts2005Patent (Other (popular science, discussion, etc.))
  • 49.
    Kubart, T.
    et al.
    Department of Solid State Electronics, Uppsala Universitet, Box 534, SE-751 21 Uppsala, Sweden.
    Trinh, David Huy
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Liljeholm, L.
    Department of Solid State Electronics, Uppsala Universitet, Box 534, SE-751 21 Uppsala, Sweden.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Nyberg, T.
    Department of Solid State Electronics, Uppsala Universitet, Box 534, SE-751 21 Uppsala, Sweden.
    Berg, S.
    Department of Solid State Electronics, Uppsala Universitet, Box 534, SE-751 21 Uppsala, Sweden.
    Experiments and Modelling 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, 565-570 p.Article in journal (Refereed)
    Abstract [en]

    Reactive sputtering from two elemental targets, aluminium and zirconium, with the addition of two reactive gases, oxygen and nitrogen, is studied experimentally as well as theoretically. The complex behaviour 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 aluminium 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.

  • 50.
    Landstrlom, L.
    et al.
    Landstrlöm, L., Ångström Laboratory, Department of Materials Chemistry, Uppsala University, SE-751 21 Uppsala, Sweden.
    Marton, Zs.
    Márton, Zs., Department of General Physics, University of Pécs, Ifjúság útja 6, H-7624 Pécs, Hungary.
    Arnold, N.
    Department of Applied Physics, Johannes Kepler University, A-4040 Linz, Austria.
    Högberg, Hans
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Boman, M.
    Ångström Laboratory, Department of Materials Chemistry, Uppsala University, SE-751 21 Uppsala, Sweden.
    Heszler, P.
    Ångstrom Laboratory, Department of Solid State Physics, Uppsala University, SE-751 21 Uppsala, Sweden, Research Group on Laser Physics, Hungarian Academy of Sciences, Box 406, Szeged H-6721, Hungary.
    In situ monitoring of size distributions and characterization of nanoparticles during W ablation in N2 atmosphere2003In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 94, no 3, 2011-2017 p.Article in journal (Refereed)
    Abstract [en]

    Amporphous WN0.3 nanoparticles were generated by pulsed excimer ablation of tungsten in a N2 ambient at atmospheric pressure. Size distributions and concentrations were monitored by dynamic mechanical analysis (DMA) and condensation particle counter (CPC) with different laser parameters and sport sizes. It was found that the fast desorptive part for which a thermal process for material removal was ruled out and the 'real' ablation gave rise to different types of size distributions.

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