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Högberg, Hans
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Publications (10 of 83) Show all publications
Hänninen, T., Schmidt, S., Ivanov, I. G., Jensen, J., Hultman, L. & Högberg, H. (2018). Silicon carbonitride thin films deposited by reactive high power impulse magnetron sputtering. Surface & Coatings Technology, 335, 248-256
Open this publication in new window or tab >>Silicon carbonitride thin films deposited by reactive high power impulse magnetron sputtering
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2018 (English)In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 335, p. 248-256Article in journal (Refereed) Published
Abstract [en]

Amorphous silicon carbonitride thin films for biomedical applications were deposited in an industrial coating unit from a silicon target in different argon/nitrogen/acetylene mixtures by reactive high power impulse magnetron sputtering (rHiPIMS). The effects of acetylene (C2H2) flow rate, substrate temperature, substrate bias voltage, and HiPIMS pulse frequency on the film properties were investigated. Low C2H2 flow rates (<10 sccm) resulted in silicon nitride-like film properties, seen from a dense morphology when viewed in cross-sectional scanning electron microscopy, a hardness up to ∼22 GPa as measured by nanoindentation, and Si-N bonds dominating over Si-C bonds in X-ray photoelectron spectroscopy core-level spectra. Higher C2H2 flows resulted in increasingly amorphous carbon-like film properties, with a granular appearance of the film morphology, mass densities below 2 g/cm3 as measured by X-ray reflectivity, and a hardness down to 4.5 GPa. Increasing substrate temperatures and bias voltages resulted in slightly higher film hardnesses and higher compressive residual stresses. The film H/E ratio showed a maximum at film carbon contents ranging between 15 and 30 at.% and at elevated substrate temperatures from 340 °C to 520 °C.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Magnetron sputtering, Silicon carbonitride, Acetylene, Hardness, H/E
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-145178 (URN)10.1016/j.surfcoat.2017.12.037 (DOI)000424720800028 ()
Funder
EU, FP7, Seventh Framework Programme, GA-310477Carl Tryggers foundation , 15:219; 14:431
Available from: 2018-02-13 Created: 2018-02-13 Last updated: 2018-04-03
Magnuson, M., Eriksson, F., Hultman, L. & Högberg, H. (2017). Bonding Structures of ZrHx Thin Films by X-ray Spectroscopy. The Journal of Physical Chemistry C, 121, 25750-25758
Open this publication in new window or tab >>Bonding Structures of ZrHx Thin Films by X-ray Spectroscopy
2017 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 121, p. 25750-25758Article in journal (Refereed) Published
Abstract [en]

The variation in local atomic structure and chemical bonding of ZrHx (x=0.15, 0.30, 1.16) magnetron sputtered thin films are investigated by Zr K-edge (1s) X-ray absorption near-edge structure and extended X-ray absorption fine structure spectroscopies. A chemical shift of the Zr K-edge towards higher energy with increasing hydrogen content is observed due to charge-transfer and an ionic or polar covalent bonding component between the Zr 4d and the H 1s states with increasing valency for Zr. We find an increase in the Zr-Zr bond distance with increasing hydrogen content from 3.160 Å in the hexagonal closest-packed metal (a-phase) to 3.395 Å in the understoichiometric d-ZrHx film (CaF2-type structure) with x=1.16 that largely resembles that of bulk d-ZrH2. For yet lower hydrogen contents, the structures are mixed a- and d-phases, while sufficient hydrogen loading (x>1) yields a pure δ-phase that is understoichiometric, but thermodynamically stable. The change in the hydrogen content and strain is discussed in relation to the corresponding change of bond lengths, hybridizations, and trends in electrical resistivity.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2017
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-143207 (URN)10.1021/acs.jpcc.7b03223 (DOI)000416496200016 ()
Funder
Swedish Energy Agency, 43606-1Swedish Foundation for Strategic Research , FUNCASE [RMA11-0029]Carl Tryggers foundation , CTS16:303, CTS14:310
Note

Funding agencies: Swedish Government Strategic Research Area in Materials Science on Functiona

Available from: 2017-11-23 Created: 2017-11-23 Last updated: 2018-06-04
Serban, A., Palisaitis, J., Junaid, M., Tengdelius, L., Högberg, H., Hultman, L., . . . Hsiao, C.-L. (2017). Magnetron Sputter Epitaxy of High-Quality GaN Nanorods on Functional and Cost-Effective Templates/Substrates. Energies, 10(9), Article ID 1322.
Open this publication in new window or tab >>Magnetron Sputter Epitaxy of High-Quality GaN Nanorods on Functional and Cost-Effective Templates/Substrates
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2017 (English)In: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 10, no 9, article id 1322Article in journal (Refereed) Published
Abstract [en]

We demonstrate the versatility of magnetron sputter epitaxy by achieving high-quality GaN nanorods on different substrate/template combinations, specifically Si, SiC, TiN/Si, ZrB2/Si, ZrB2/SiC, Mo, and Ti. Growth temperature was optimized on Si, TiN/Si, and ZrB2/Si, resulting in increased nanorod aspect ratio with temperature. All nanorods exhibit high purity and quality, proved by the strong bandedge emission recorded with cathodoluminescence spectroscopy at room temperature as well as transmission electron microscopy. These substrates/templates are affordable compared to many conventional substrates, and the direct deposition onto them eliminates cumbersome post-processing steps in device fabrication. Thus, magnetron sputter epitaxy offers an attractive alternative for simple and affordable fabrication in optoelectronic device technology.

Place, publisher, year, edition, pages
Basel, Switzerland: MDPI AG, 2017
Keywords
GaN, nanorods, Si, SiC, Ti, Mo, TiN and ZrB2 templates, magnetron sputtering, epitaxy
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-141597 (URN)10.3390/en10091322 (DOI)000411225200078 ()2-s2.0-85029362447 (Scopus ID)
Note

Funding agencies: Swedish Research Council (VR) [621-2012-4420, 621-2013-5360, 2016-04412]; Swedish Governmental Agency for Innovation Systems (VINNOVA) under the VINNMER international qualification program; Swedish Foundation for Strategic Research (SSF) through the Resea

Available from: 2017-10-02 Created: 2017-10-02 Last updated: 2018-05-03Bibliographically approved
Henry, A., Chubarov, M., Czigany, Z., Garbrecht, M. & Högberg, H. (2016). Early stages of growth and crystal structure evolution of boron nitride thin films. Paper presented at 6th International Symposium on Growth of III-Nitrides (ISGN). Japanese Journal of Applied Physics, 55(5), 05FD06
Open this publication in new window or tab >>Early stages of growth and crystal structure evolution of boron nitride thin films
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2016 (English)In: Japanese Journal of Applied Physics, ISSN 0021-4922, E-ISSN 1347-4065, Vol. 55, no 5, p. 05FD06-Article in journal (Refereed) Published
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

Place, publisher, year, edition, pages
IOP PUBLISHING LTD, 2016
National Category
Physical Sciences
Identifiers
urn:nbn:se:liu:diva-128949 (URN)10.7567/JJAP.55.05FD06 (DOI)000374697600030 ()
Conference
6th International Symposium on Growth of III-Nitrides (ISGN)
Available from: 2016-06-09 Created: 2016-06-07 Last updated: 2018-03-23
Tengdelius, L., Broitman, E., Lu, J., Eriksson, F., Birch, J., Nyberg, T., . . . Högberg, H. (2016). Hard and elastic epitaxial ZrB2 thin films on Al2O3(0001) substrates deposited by magnetron sputtering from a ZrB2 compound target. Acta Materialia, 111, 166-172
Open this publication in new window or tab >>Hard and elastic epitaxial ZrB2 thin films on Al2O3(0001) substrates deposited by magnetron sputtering from a ZrB2 compound target
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2016 (English)In: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 111, p. 166-172Article in journal (Refereed) Published
Abstract [en]

Zirconium diboride (ZrB2) exhibits high hardness and high melting point, which is beneficial for applications in for e.g. metal cutting. However, there is limited data on the mechanical properties of ZrB2 films and no data on epitaxial films. In this study, ZrB2(0001) thin films, with thicknesses up to 1.2 μm, have been deposited on Al2O3(0001) substrates by direct current magnetron sputtering from a compound target. X-ray diffraction and transmission electron microscopy show that the films grow epitaxially with two domain types exhibiting different in-plane epitaxial relationships to the substrate. The out-of-plane epitaxial relationship was determined to ZrB2(0001)|Al2O3(0001) and the in-plane relationships of the two domains to ZrB2[100]‖Al2O3[100] and ZrB2[110]‖Al2O3[100]. Mechanical properties of the films, evaluated by nanoindentation, showed that all films exhibit hardness values above 45 GPa, a reduced Young's modulus in the range 350–400 GPa, and a high elastic recovery of 70% at an applied load of 9000 μN.

Place, publisher, year, edition, pages
Elsevier, 2016
Keywords
Borides, Epitaxial growth, Mechanical properties, Nanoindentation, Sputter deposition
National Category
Physical Sciences
Identifiers
urn:nbn:se:liu:diva-128612 (URN)10.1016/j.actamat.2016.03.064 (DOI)000375812100018 ()
Note

Funding agencies: Swedish Research Council (VR) [621-2010-3921]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009-00971]; Knut and Alice Wallenberg Foundation

Available from: 2016-05-25 Created: 2016-05-25 Last updated: 2017-11-30Bibliographically approved
Broitman, E., Tengdelius, L., Hangen, U. D., Lu, J., Hultman, L. & Högberg, H. (2016). High-temperature nanoindentation of epitaxial ZrB2 thin films. Scripta Materialia, 124, 117-120
Open this publication in new window or tab >>High-temperature nanoindentation of epitaxial ZrB2 thin films
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2016 (English)In: Scripta Materialia, ISSN 1359-6462, E-ISSN 1872-8456, Vol. 124, p. 117-120Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Elsevier, 2016
Keywords
Sputtering; Borides; Ceramic thin film; Nanoindentation; Transmission electron microscopy
National Category
Physical Sciences
Identifiers
urn:nbn:se:liu:diva-130917 (URN)10.1016/j.scriptamat.2016.06.033 (DOI)000383294200027 ()
Note

Funding agencies: Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]; Swedish Research Council (VR) [621-2010-3921]

Available from: 2016-08-31 Created: 2016-08-31 Last updated: 2017-11-21Bibliographically approved
Hänninen, T., Schmidt, S., Wissting, J., Jensen, J., Hultman, L. & Högberg, H. (2016). Stoichiometric silicon oxynitride thin films reactively sputtered in Ar/N2O plasmas by HiPIMS. Journal of Physics D: Applied Physics, 49(13), Article ID 135309.
Open this publication in new window or tab >>Stoichiometric silicon oxynitride thin films reactively sputtered in Ar/N2O plasmas by HiPIMS
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2016 (English)In: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 49, no 13, article id 135309Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Institute of Physics (IOP), 2016
National Category
Physical Sciences
Identifiers
urn:nbn:se:liu:diva-123382 (URN)10.1088/0022-3727/49/13/135309 (DOI)000371908800023 ()
Note

Funding agencies:  Carl Tryggers Foundation for Scientific Research; European Union under the LifeLongJoints Project [GA-310477]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009-00971]

Available from: 2015-12-15 Created: 2015-12-15 Last updated: 2018-02-13Bibliographically approved
Sarakinos, K., Greczynski, G., Elofsson, V., Magnfält, D., Högberg, H. & Alling, B. (2016). Theoretical and experimental study of metastable solid solutions and phase stability within the immiscible Ag-Mo binary system. Journal of Applied Physics, 119(9), 095303
Open this publication in new window or tab >>Theoretical and experimental study of metastable solid solutions and phase stability within the immiscible Ag-Mo binary system
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2016 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 119, no 9, p. 095303-Article in journal (Refereed) Published
Abstract [en]

Metastable solid solutions are phases that are synthesized far from thermodynamic equilibrium and offer a versatile route to design materials with tailor-made functionalities. One of the most investigated classes of metastable solid solutions with widespread technological implications is vapor deposited ternary transition metal ceramic thin films (i.e., nitrides, carbides, and borides). The vapor-based synthesis of these ceramic phases involves complex and difficult to control chemical interactions of the vapor species with the growing film surface, which often makes the fundamental understanding of the composition-properties relations a challenging task. Hence, in the present study, we investigate the phase stability within an immiscible binary thin film system that offers a simpler synthesis chemistry, i.e., the Ag-Mo system. We employ magnetron co-sputtering to grow Ag1-xMox thin films over the entire composition range along with x-ray probes to investigate the films structure and bonding properties. Concurrently, we use density functional theory calculations to predict phase stability and determine the effect of chemical composition on the lattice volume and the electronic properties of Ag-Mo solid solutions. Our combined theoretical and experimental data show that Mo-rich films (x &gt;= similar to 0.54) form bcc Mo-Ag metastable solid solutions. Furthermore, for Ag-rich compositions (x &lt;= similar to 0.21), our data can be interpreted as Mo not being dissolved in the Ag fcc lattice. All in all, our data show an asymmetry with regards to the mutual solubility of Ag and Mo in the two crystal structures, i.e., Ag has a larger propensity for dissolving in the bcc-Mo lattice as compared to Mo in the fcc-Ag lattice. We explain these findings in light of isostructural short-range clustering that induces energy difference between the two (fcc and bcc) metastable phases. We also suggest that the phase stability can be explained by the larger atomic mobility of Ag atoms as compared to that of Mo. The mechanisms suggested herein may be of relevance for explaining phase stability data in a number of metastable alloys, such as ternary transition metal-aluminum-nitride systems. (C) 2016 AIP Publishing LLC.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2016
National Category
Physical Sciences
Identifiers
urn:nbn:se:liu:diva-127275 (URN)10.1063/1.4942840 (DOI)000372351900057 ()
Note

Funding Agencies|Linkoping University [Dnr-LiU-2015-01510]; Swedish Research Council (VR) [621-2011-4417, 330-2014-6336]; VINN Excellence Center Functional Nanoscale Materials (FunMat); Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009-00971]

Available from: 2016-04-20 Created: 2016-04-19 Last updated: 2017-11-30Bibliographically approved
Goyenola, C., Lai, C.-C., Näslund, L.-Å., Lu, J., Högberg, H., Hultman, L., . . . Gueorguiev, G. K. (2016). Theoretical prediction and synthesis of CSxFy thin films. The Journal of Physical Chemistry C, 120(17), 9527-9534
Open this publication in new window or tab >>Theoretical prediction and synthesis of CSxFy thin films
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2016 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 120, no 17, p. 9527-9534Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2016
National Category
Physical Sciences
Identifiers
urn:nbn:se:liu:diva-121470 (URN)10.1021/acs.jpcc.6b02718 (DOI)000375631100060 ()
Note

funding agencies: Swedish Foundation for Strategic Research (SSF) [RMA11-0029]; Carl Trygger Foundation for Scientific Research; Swedish Research Council [642-2013-8020]; ERC [258509]; Knut and Alice Wallenberg Foundation; Swedish Government Strategic Research Area in Materials at Linkoping University 

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Available from: 2015-09-21 Created: 2015-09-21 Last updated: 2017-12-04Bibliographically approved
Tengdelius, L., Lu, J., Forsberg, U., Li, X., Hultman, L., Janzén, E. & Högberg, H. (2016). ZrB2 thin films deposited on GaN(0001) by magnetron sputtering from a ZrB2 target. Journal of Crystal Growth, 453, 71-76
Open this publication in new window or tab >>ZrB2 thin films deposited on GaN(0001) by magnetron sputtering from a ZrB2 target
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2016 (English)In: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 453, p. 71-76Article in journal (Refereed) Published
Abstract [en]

ZrB2 films were deposited on 900 °C-preheated or non-preheated GaN(0001) surfaces by direct current magnetron sputtering from a compound target. Analytical transmission electron microscopy and scanning transmission electron microscopy with energy dispersive X-ray spectroscopy and electron energy loss spectroscopy revealed a 0001 fiber textured ZrB2 film growth following the formation of a ~2 nm thick amorphous BN layer onto the GaN(0001) at a substrate temperature of 900 °C. The amorphous BN layer remains when the substrate temperature is lowered to 500 °C or when the preheating step is removed from the process and results in the growth of polycrystalline ZrB2 films. The ZrB2 growth phenomena on GaN(0001) is compared to on 4H-SiC(0001), Si(111), and Al2O3(0001) substrates, which yield epitaxial film growth. The decomposition of the GaN surface during vacuum processing during BN interfacial layer formation is found to impede epitaxial growth of ZrB2.

Place, publisher, year, edition, pages
Elsevier, 2016
Keywords
A1. X-ray diffraction; A1. Interfaces; A1. Energy-dispersive X-ray spectroscopy; A1. Electron energy loss spectroscopy; A3. Physical vapor deposition processes; B1. Borides
National Category
Physical Sciences
Identifiers
urn:nbn:se:liu:diva-130920 (URN)10.1016/j.jcrysgro.2016.08.011 (DOI)000386984000012 ()
Available from: 2016-08-31 Created: 2016-08-31 Last updated: 2017-11-21Bibliographically approved
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