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BETA
Hultman, Lars, ProfessorORCID iD iconorcid.org/0000-0002-2837-3656
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Publications (10 of 627) Show all publications
Engberg, D. L. J., Tengdelius, L., Högberg, H., Thuvander, M. & Hultman, L. (2019). Atom probe tomography field evaporation characteristics and compositional corrections of ZrB2. Materials Characterization, 156, Article ID 109871.
Open this publication in new window or tab >>Atom probe tomography field evaporation characteristics and compositional corrections of ZrB2
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2019 (English)In: Materials Characterization, ISSN 1044-5803, E-ISSN 1873-4189, Vol. 156, article id 109871Article in journal (Refereed) Published
Abstract [en]

The microstructure of stoichiometric ZrB2.0 and B over-stoichiometric ZrB2.5 thin films has been studied using atom probe tomography (APT), X-ray diffraction, and transmission electron microscopy. Both films consist of columnar ZrB2 grains with AlB2-type crystal structure. The narrow stoichiometry range of ZrB2 results in the presence of separate disordered B-rich boundaries even in ZrB2.0. At higher average B content, specifically ZrB2.5, the formation of a continuous network around the sides of the ZrB2 columns is promoted. In addition, the APT field evaporation characteristics of ZrB2 and its influence on the measured local composition has been studied and compared to the average composition from elastic recoil detection analysis (ERDA). Differences in the measured average compositions of the two techniques are explained by the APT detector dead-time/space. A new pile-up pairs correction procedure based on co-evaporation correlation data was thus employed here for the APT data and compared with the 10B-method (the B equivalence of the 13C-method), as well as the combination of both methods. In ZrB2.0, all of the applied compositional correction methods were found to reduce the compositional difference when appropriate isotopic abundances were used. In ZrB2.5, the inhomogeneity of the film likely increased the local APT composition to such an extent that even conservative correction procedures overestimated the B content compared to the ERDA reference. The strengths of the pile-up pairs correction compared the 10B and the combined methods are higher precision, due to it being less dependent on the accuracy of estimated isotopic abundances, and that the correction itself is not dependent on careful background correction of the mass spectrum.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Atom probe tomography (APT), Zirconium diboride (ZrB), Field evaporation characteristics of borides, Elastic recoil detection analysis (ERDA), Compositional correction procedures, Transition metal diborides
National Category
Physical Sciences
Identifiers
urn:nbn:se:liu:diva-160356 (URN)10.1016/j.matchar.2019.109871 (DOI)
Available from: 2019-09-19 Created: 2019-09-19 Last updated: 2019-09-20Bibliographically approved
Magnuson, M., Tengdelius, L., Greczynski, G., Eriksson, F., Jensen, J., Lu, J., . . . Högberg, H. (2019). Compositional dependence of epitaxial Tin+1SiCn MAX-phase thin films grown from a Ti3SiC2 compound target. Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, 37(2), Article ID 021506.
Open this publication in new window or tab >>Compositional dependence of epitaxial Tin+1SiCn MAX-phase thin films grown from a Ti3SiC2 compound target
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2019 (English)In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 37, no 2, article id 021506Article in journal (Refereed) Published
Abstract [en]

The authors investigate sputtering of a Ti3SiC2 compound target at temperatures ranging from RT (no applied external heating) to 970 °C as well as the influence of the sputtering power at 850 °C for the deposition of Ti3SiC2 films on Al2O3(0001) substrates. Elemental composition obtained from time-of-flight energy elastic recoil detection analysis shows an excess of carbon in all films, which is explained by differences in the angular distribution between C, Si, and Ti, where C scatters the least during sputtering. The oxygen content is 2.6 at. % in the film deposited at RT and decreases with increasing deposition temperature, showing that higher temperatures favor high purity films. Chemical bonding analysis by x-ray photoelectron spectroscopy shows C–Ti and Si–C bonding in the Ti3SiC2 films and Si–Si bonding in the Ti3SiC2 compound target. X-ray diffraction reveals that the phases Ti3SiC2, Ti4SiC3, and Ti7Si2C5 can be deposited from a Ti3SiC2 compound target at substrate temperatures above 850 °C and with the growth of TiC and the Nowotny phase Ti5Si3Cx at lower temperatures. High-resolution scanning transmission electron microscopy shows epitaxial growth of Ti3SiC2, Ti4SiC3, and Ti7Si2C5 on TiC at 970 °C. Four-point probe resistivity measurements give values in the range ∼120 to ∼450 μΩ cm and with the lowest values obtained for films containing Ti3SiC2, Ti4SiC3, and Ti7Si2C5.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2019
National Category
Physical Sciences
Identifiers
urn:nbn:se:liu:diva-154004 (URN)10.1116/1.5065468 (DOI)000460437200051 ()
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 Energy Research [43606-1]; Carl Tryggers Foundation [CTS16:303, CTS14:310, CTS 17:166]; Knut 

Available from: 2019-01-22 Created: 2019-01-22 Last updated: 2019-03-20Bibliographically approved
Magnuson, M., Greczynski, G., Eriksson, F., Hultman, L. & Högberg, H. (2019). Electronic Structure of ß-Ta Films from X-ray Photoelectron Spectroscopy and First-principles Calculations. Applied Surface Science, 470, 607-612
Open this publication in new window or tab >>Electronic Structure of ß-Ta Films from X-ray Photoelectron Spectroscopy and First-principles Calculations
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2019 (English)In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 470, p. 607-612Article in journal (Refereed) Published
Abstract [en]

The electronic structure and chemical bonding of ß-Ta synthesized as a thin 001-oriented film (space group P 21m) is investigated by 4f core level and valence band X-ray photoelectron spectroscopy and compared to α-Ta bulk. For the b-phase, the 4f7/2 peak is located at 21.91 eV and with the 4f5/2 at 23.81 eV which is 0.16 eV higher compared to the corresponding 4f peaks of the a-Ta reference. We suggest that this chemical shift originates from higher resistivity and tensile strain in the ß-Ta film. Furthermore, the 5d-5s states at the bottom of the valence band are shifted by 0.75 eV towards higher binding energy in ß-Ta compared to α-Ta. This is a consequence of the lower number of nearest neighbors with four in ß-Ta compared to eight in the α-Ta phase. The difference in the electronic structures, spectral line shapes of the valence band and the energy positions of the Ta 4f, 5p core-levels of b-Ta versus a-Ta are discussed in relation to calculated states of ß-Ta and α-Ta. In particular, the lower number of states at the Fermi level of ß-Ta (0.557 states/eV/atom) versus α-Ta (1.032 states/eV/atom) that according to Mott’s law should decrease the conductivity in metals and affect the stability by charge redistribution in the valence band. This is experimentally supported from resistivity measurements of the film yielding a value of ~170 µW cm in comparison to α-Ta bulk with a reported value of ~13.1 µW cm.

Keywords
β-Ta films, Valence band measurements, First-principles calculations, X-ray photoelectron spectroscopy, High power impulse magnetron sputtering
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-152876 (URN)10.1016/j.apsusc.2018.11.096 (DOI)000454997100069 ()
Note

Funding agencies: Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linkoping University [2009-00971]; Swedish Energy Research [43606-1]; Carl Tryggers Foundation [CTS16:303, CTS14:310, CTS 17:166]; Knut and Alice Wallenber

Available from: 2018-11-26 Created: 2018-11-26 Last updated: 2019-01-21
Landälv, L., Carlström, C.-F., Lu, J., Primetzhofer, D., Jöesaar, M. J., Ahlgren, M., . . . Eklund, P. (2019). Phase composition and transformations in magnetron-sputtered (Al,V)2O3 coatings. Thin Solid Films
Open this publication in new window or tab >>Phase composition and transformations in magnetron-sputtered (Al,V)2O3 coatings
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2019 (English)In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731Article in journal (Refereed) In press
Abstract [en]

Coatings of (Al1-xVx)2O3, with x ranging from 0 to 1, were deposited by pulsed DC reactive sputter deposition on Si(100) at a temperature of 550 °C. XRD showed three different crystal structures depending on V-metal fraction in the coating: α-V2O3 rhombohedral structure for 100 at.% V, a defect spinel structure for the intermediate region, 63–42 at.% V. At lower V-content, 18 and 7 at.%, a gamma-alumina-like solid solution was observed, shifted to larger d-spacing compared to pure γ-Al2O3. The microstructure changes from large columnar faceted grains for α-V2O3 to smaller equiaxed grains when lowering the vanadium content towards pure γ-Al2O3. Annealing in air resulted in formation of V2O5 crystals on the surface of the coating after annealing to 500 °C for 42 at.% V and 700 °C for 18 at.% V metal fraction respectively. The highest thermal stability was shown for pure γ-Al2O3-coating, which transformed to α-Al2O3 after annealing to 1100 °C. Highest hardness was observed for the Al-rich oxides, ~24 GPa. The latter decreased with increasing V-content, larger than 7 at.% V metal fraction. The measured hardness after annealing in air decreased in conjunction with the onset of further oxidation of the coatings.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Aluminum vanadium oxide Pulsed DC magnetron sputtering Annealing V2O5 AlVO4 AlVO3
National Category
Physical Sciences
Identifiers
urn:nbn:se:liu:diva-159749 (URN)10.1016/j.tsf.2019.06.019 (DOI)
Available from: 2019-08-20 Created: 2019-08-20 Last updated: 2019-09-06Bibliographically approved
Magnuson, M., Tengdelius, L., Eriksson, F., Samuelsson, M., Broitman, E., Greczynski, G., . . . Högberg, H. (2019). Reactive magnetron sputtering of tungsten target in krypton/trimethylboron atmosphere. Thin Solid Films, 688, Article ID 137384.
Open this publication in new window or tab >>Reactive magnetron sputtering of tungsten target in krypton/trimethylboron atmosphere
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2019 (English)In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 688, article id 137384Article in journal (Refereed) Published
Abstract [en]

W-B-C films were deposited on Si(100) substrates held at elevated temperature by reactive sputtering from a W target in Kr/trimethylboron (TMB) plasmas. Quantitative analysis by Xray photoelectron spectroscopy (XPS) shows that the films are W-rich between ~ 73 and ~ 93 at.% W. The highest metal content is detected in the film deposited with 1 sccm TMB. The C and B concentrations increase with increasing TMB flow to a maximum of ~18 and ~7 at.%, respectively, while the O content remains nearly constant at 2-3 at.%. Chemical bonding structure analysis performed after samples sputter-cleaning reveals C-W and B-W bonding and no detectable W-O bonds. During film growth with 5 sccm TMB and 500 o C or with 10 sccm TMB and 300-600 o C thin film X-ray diffraction shows the formation of cubic 100-oriented WC1-x with a possible solid solution of B. Lower flows and lower growth temperatures favor growth of W and W2C, respectively. Depositions at 700 and 800 o C result in the formation of WSi2 due to a reaction with the substrate. At 900 o C, XPS analysis shows ~96 at.% Si in the film due to Si interdiffusion. Scanning electron microscopy images reveal a fine-grained microstructure for the deposited WC1-x films. Nanoindentation gives hardness values in the range from ~23 to ~31 GPa and reduced elastic moduli between ~220 and 280 GPa in the films deposited at temperatures lower than 600 o C. At higher growth temperatures the hardness decreases by a factor of 3 to 4 following the formation of WSi2 at 700-800 o C and Si-rich surface at 900 o C.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
W-B-C films, reactive magnetron sputtering, trimethylboron, nanoindentation, Xray photoelectron spectroscopy, thin film X-ray diffraction, Scanning Electron Microscope
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:liu:diva-160243 (URN)10.1016/j.tsf.2019.06.034 (DOI)2-s2.0-85067891667 (Scopus ID)
Available from: 2019-09-13 Created: 2019-09-13 Last updated: 2019-09-18Bibliographically approved
Magnuson, M., Tengdelius, L., Greczynski, G., Hultman, L. & Högberg, H. (2018). ­Chemical Bonding in Epitaxial ZrB2 Studied by X-ray Spectroscopy. Thin Solid Films, 649, 89-96
Open this publication in new window or tab >>­Chemical Bonding in Epitaxial ZrB2 Studied by X-ray Spectroscopy
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2018 (English)In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 649, p. 89-96Article in journal (Refereed) Published
Abstract [en]

The chemical bonding in an epitaxial ZrB2 film is investigated by Zr K-edge (1s) X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectroscopies and compared to the ZrB2 compound target from which the film was synthesized as well as a bulk α-Zr reference. Quantitative analysis of X-ray Photoelectron Spectroscopy spectra reveals at the surface: ~5% O in the epitaxial ZrB2 film, ~19% O in the ZrB2 compound target and ~22% O in the bulk α-Zr reference after completed sputter cleaning. For the ZrB2 compound target, X-ray diffraction (XRD) shows weak but visible   11, 111, and 220 peaks from monoclinic ZrO2 together with peaks from ZrB2 and where the intensity distribution for the ZrB2 peaks show a randomly oriented target material.  For the bulk α-Zr reference no peaks from any crystalline oxide were visible in the diffractogram recorded from the 0001-oriented metal. The Zr K-edge absorption from the two ZrB2 samples demonstrate more pronounced oscillations for the epitaxial ZrB2 film than in the bulk ZrB2 attributed to the high atomic ordering within the columns of the film. The XANES exhibits no pre-peak due to lack of p-d hybridization in ZrB2, but with a chemical shift towards higher energy of 4 eV in the film and 6 eV for the bulk compared to α-Zr (17.993 keV) from the charge-transfer from Zr to B. The 2 eV larger shift in bulk ZrB2 material suggests higher oxygen content than in the epitaxial film, which is supported by XPS. In EXAFS, the modelled cell-edge in ZrB2 is slightly smaller in the thin film (a=3.165 Å, c=3.520 Å) in comparison to the bulk target material (a=3.175 Å, c=3.540 Å) while in hexagonal closest-packed metal (α-phase, a=3.254 Å, c=5.147 Å). The modelled coordination numbers show that the EXAFS spectra of the epitaxial ZrB2 film is highly anisotropic with strong in-plane contribution, while the bulk target material is more isotropic. The Zr-B distance in the film of 2.539 Å is in agreement with the calculated value from XRD data of 2.542 Å. This is slightly shorter compared to that in the ZrB2 compound target 2.599 Å, supporting the XANES results of a higher atomic order within the columns of the film compared to bulk ZrB2.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Zirconium boride, thin films, bond distances, chemical bonding, X-ray spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction
National Category
Physical Sciences
Identifiers
urn:nbn:se:liu:diva-144578 (URN)10.1016/j.tsf.2018.01.021 (DOI)000427524100015 ()
Note

Funding agencies: Swedish Energy Research [43606-1]; Swedish Foundation for Strategic Research (SSF) through the synergy grant FUNCASE [RMA11-0029]; Carl Trygger Foundation [CTS16:303, CTS14:310]; Swedish Research Council (VR) [621-2010 3921]; Knut and Alice Wallenberg Fou

Available from: 2018-01-29 Created: 2018-01-29 Last updated: 2018-11-29Bibliographically approved
Junaid, M., Hsiao, C.-L., Chen, Y.-T., Lu, J., Palisaitis, J., Persson, P. O., . . . Birch, J. (2018). Effects of N2 Partial Pressure on Growth, Structure, and Optical Properties of GaN Nanorods Deposited by Liquid-Target Reactive Magnetron Sputter Epitaxy. Nanomaterials, 8(4), Article ID 223.
Open this publication in new window or tab >>Effects of N2 Partial Pressure on Growth, Structure, and Optical Properties of GaN Nanorods Deposited by Liquid-Target Reactive Magnetron Sputter Epitaxy
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2018 (English)In: Nanomaterials, ISSN 2079-4991, Vol. 8, no 4, article id 223Article in journal (Other academic) Published
Abstract [en]

GaN nanorods, essentially free from crystal defects and exhibiting very sharp band-edge luminescence, have been grown by reactive direct-current magnetron sputter epitaxy onto Si (111) substrates at a low working pressure of 5 mTorr. Upon diluting the reactive N2 working gas with a small amount of Ar (0.5 mTorr), we observed an increase in the nanorod aspect ratio from 8 to ~35, a decrease in the average diameter from 74 to 35 nm, and a two-fold increase in nanorod density. With further dilution (Ar = 2.5 mTorr), the aspect ratio decreased to 14, while the diameter increased to 60 nm and the nanorod density increased to a maximum of 2.4 × 109 cm−2. Yet, lower N2 partial pressures eventually led to the growth of continuous GaN films. The observed morphological dependence on N2 partial pressure is explained by a change from N-rich to Ga-rich growth conditions, combined with reduced GaN-poisoning of the Ga-target as the N2 gas pressure is reduced. Nanorods grown at 2.5 mTorr N2 partial pressure exhibited a high intensity 4 K photoluminescence neutral donor bound exciton transitions (D0XA) peak at ~3.479 eV with a full-width-at-half-maximum of 1.7 meV. High-resolution transmission electron microscopy corroborated the excellent crystalline quality of the nanorods.

Place, publisher, year, edition, pages
Basel, Switzerland: MDPI, 2018
Keywords
GaN, nanorods, X-ray diffraction, TEM, photoluminescence, magnetron sputter epitaxy, sputtering
National Category
Condensed Matter Physics Nano Technology
Identifiers
urn:nbn:se:liu:diva-84654 (URN)10.3390/nano8040223 (DOI)000434889100044 ()
Note

Funding agencies: Swedish Research Council (VR) [621-2013-5360, 621-2012-4420, 2016-04412]; Swedish Government Strategic Research Area Grant in Materials Science AFM-SFO MatLiU [2009-00971]; Knut and Alice Wallenberg Foundation

Available from: 2018-04-09 Created: 2012-10-16 Last updated: 2018-06-28Bibliographically approved
Greczynski, G., Primetzhofer, D. & Hultman, L. (2018). Reference binding energies of transition metal carbides by core-level x-ray photoelectron spectroscopy free from Ar+ etching artefacts. Applied Surface Science, 436, 102-110
Open this publication in new window or tab >>Reference binding energies of transition metal carbides by core-level x-ray photoelectron spectroscopy free from Ar+ etching artefacts
2018 (English)In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 436, p. 102-110Article in journal (Refereed) Published
Abstract [en]

We report x-ray photoelectron spectroscopy (XPS) core level binding energies (BEs) for the widely-applicable groups IVb-VIb transition metal carbides (TMCs) TiC, VC, CrC, ZrC, NbC, MoC, HfC, TaC, and WC. Thin film samples are grown in the same deposition system, by dc magnetron co-sputtering from graphite and respective elemental metal targets in Ar atmosphere. To remove surface contaminations resulting from exposure to air during sample transfer from the growth chamber into the XPS system, layers are either (i) Ar+ ion-etched or (ii) UHV-annealed in situ prior to XPS analyses. High resolution XPS spectra reveal that even gentle etching affects the shape of core level signals, as well as BE values, which are systematically offset by 0.2-0.5 eV towards lower BE. These destructive effects of Ar+ ion etch become more pronounced with increasing the metal atom mass due to an increasing carbon-to-metal sputter yield ratio. Systematic analysis reveals that for each row in the periodic table (3d, 4d, and 5d) C 1s BE increases from left to right indicative of a decreased charge transfer from TM to C atoms, hence bond weakening. Moreover, C 1s BE decreases linearly with increasing carbide/metal melting point ratio. Spectra reported here, acquired from a consistent set of samples in the same instrument, should serve as a reference for true deconvolution of complex XPS cases, including multinary carbides, nitrides, and carbonitrides. (C) 2017 Elsevier B.V. All rights reserved.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE BV, 2018
Keywords
TiC; XPS; Magnetron sputtering; Binding energy; VC; CrC; NbC; ZrC; MoC; HfC; TaC; WC
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:liu:diva-145736 (URN)10.1016/j.apsusc.2017.11.264 (DOI)000425723100011 ()
Note

Funding Agencies|Aforsk foundation [16-359]; Carl Tryggers Stiftelse [CTS 15:219, CTS 14:431]; Knut and Alice Wallenberg Foundation Scholar [KAW2016.0358]; Swedish Foundation for Strategic Research (SSF) [RIF14-0053]

Available from: 2018-03-22 Created: 2018-03-22 Last updated: 2018-04-20
Engberg, D., Johnson, L. J. S., Jensen, J., Thuvander, M. & Hultman, L. (2018). Resolving Mass Spectral Overlaps in Atom Probe Tomography by Isotopic Substitutions: Case of TiSi15N. Ultramicroscopy, 184, 51-60
Open this publication in new window or tab >>Resolving Mass Spectral Overlaps in Atom Probe Tomography by Isotopic Substitutions: Case of TiSi15N
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2018 (English)In: Ultramicroscopy, ISSN 0304-3991, E-ISSN 1879-2723, Vol. 184, p. 51-60Article in journal (Refereed) Published
Abstract [en]

Mass spectral overlaps in atom probe tomography (APT) analyses of complex compounds typically limit the identification of elements and microstructural analysis of a material. This study concerns the TiSiN system, chosen because of severe mass-to-charge-state ratio overlaps of the 14N+ and 28Si2+ peaks as well as the 14N and 28Si2+ peaks. By substituting 14N with 15N, mass spectrum peaks generated by ions composed of one or more N atoms will be shifted toward higher mass-to-charge-state ratios, thereby enabling the separation of N from the predominant Si isotope. We thus resolve thermodynamically driven Si segregation on the nanometer scale in cubic phase Ti1-xSix15N thin films for Si contents 0.08 ≤ x ≤ 0.19 by APT, as corroborated by transmission electron microscopy. The APT analysis yields a composition determination that is in good agreement with energy dispersive X-ray spectroscopy and elastic recoil detection analyses. Additionally, a method for determining good voxel sizes for visualizing small-scale fluctuations is presented and demonstrated for the TiSiN system.

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Physical Sciences
Identifiers
urn:nbn:se:liu:diva-122721 (URN)10.1016/j.ultramic.2017.08.004 (DOI)000415650200007 ()28850866 (PubMedID)
Note

Funding Agencies:VINN Excellence Center on Functional Nanoscale Materials (FunMat) [2007-00863]; Swedish Research Council (VR) project [2013-4018]; Swedish Government Strategic Research Area Grant in Materials Science (Grant SFO Mat-LiU) on Advanced Functional Materials [2009-00971]; Knut and Alice Wallenberg Project Isotope

Available from: 2015-11-18 Created: 2015-11-18 Last updated: 2019-08-01Bibliographically approved
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
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-2837-3656

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