| 1. |
- Andersson, Jon Martin, et al.
(författare)
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Phase control of Al2O3 thin films grown at low temperatures
- 2006
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Ingår i: Thin Solid Films. - : Elsevier. - 0040-6090 .- 1879-2731. ; 513:1-2, s. 57-59
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Tidskriftsartikel (refereegranskat)abstract
- Low-temperature growth (500 °C) of α-Al2O3 thin films by reactive magnetron sputtering was achieved for the first time. The films were grown onto Cr2O3 nucleation layers and the effects of the total and O2 partial pressures were investigated. At 0.33 Pa total pressure and ≥ 16 mPa O2 partial pressure α-Al2O3 films formed, while at lower O2 pressure or higher total pressure (0.67 Pa), only γ phase was detected in the films (which were all stoichiometric). Based on these results we suggest that α phase formation was promoted by a high energetic bombardment of the growth surface. This implies that the phase content of Al2O3 films can be controlled by controlling the energy of the depositing species. The effect of residual H2O (10− 4 Pa) on the films was also studied, showing no change in phase content and no incorporated H (< 0.1%). Overall, these results are of fundamental importance in the further development of low-temperature Al2O3 growth processes.
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| 2. |
- Blomqvist, M., et al.
(författare)
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Structural and tribological properties of cluster-assembled CNx films
- 2007
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Ingår i: Applied Physics A. - : Springer Science and Business Media LLC. - 0947-8396 .- 1432-0630. ; 87:4, s. 767-772
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Tidskriftsartikel (refereegranskat)abstract
- We report the structural and tribological characterization of nanostructured CNx thin films produced by the deposition of a supersonic carbon cluster beam assisted by nitrogen ion bombardment. The influence of the deposition parameters on the chemical composition and structure of the films has been systematically studied by X-ray photoelectron spectroscopy, elastic recoil detection analysis, transmission electron microscopy and atomic force microscopy. Depending on the deposition parameters, the films show a structure ranging from amorphous to disordered graphitic with interlinked planes. Nitrogen content depends on the nitrogen ion kinetic energy. The films have a very low density with a high surface roughness. Friction measurements at the nanoscale show a correlation between nitrogen content and mechanical properties of the system.
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| 3. |
- Eriksson, Fredrik, et al.
(författare)
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14.5% near-normal incidence reflectance of Cr/Sc x-ray multilayer mirrors for the water window
- 2003
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Ingår i: Optics Letters. - 0146-9592 .- 1539-4794. ; 28:24, s. 2494-2496
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Tidskriftsartikel (refereegranskat)abstract
- Cr/Sc multilayer mirrors, synthesized by ion-assisted magnetron sputter deposition, are proved to have a high near-normal reflectivity of R = 14.5% at a grazing angle of 87.5degrees measured at the wavelength A = 3.11 nm, which is an improvement of more than 31% compared with previously published results. Elastic recoil detection analyses show that the mirrors contained as much as 15 at. % of N and traces of C and O. Soft x-ray reflectivity simulations reveal interface widths of sigma = 0.34 nm and an exceptionally small layer thickness drift of similar to1.6 X 10(-5) nm/multilayer period throughout the stack. Simulations show that a reflectivity of R = 25.6% is attainable if impurities and layer thickness drift can be eliminated. The abrupt interfaces are achieved with ion assistance with a low ion energy of 24 eV and high ion-to-metal flux ratios of 7.1 and 23.1 during Cr and Se sputter deposition, respectively. In addition, a near-normal incidence reflectivity of 5.5% for the C VI emission line (lambda = 3.374 nm) from a laser plasma source was verified.
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| 4. |
- Gago, R., et al.
(författare)
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Synthesis of carbon nitride thin films by low-energy ion beam assisted evaporation : On the mechanisms for fullerene-like microstructure formation
- 2005
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Ingår i: Thin Solid Films. - : Elsevier BV. - 0040-6090 .- 1879-2731. ; 483:1-2, s. 89-94
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Tidskriftsartikel (refereegranskat)abstract
- Carbon nitride (CNx) thin films were grown at different substrate temperatures by low-energy (<100 eV) ion beam assistance deposition (LE-IBAD) in order to discern possible formation mechanisms of a fullerene-like (FL) microstructure. The samples are compared to those of well-structured FL-CNx films synthesized by reactive magnetron sputtering (MS). The comparison yields similar trends for both techniques, such as limitation of the nitrogen content at 20–25 at.%, dominance of sp2 hybrids, as well as thermally activated chemical desorption of CxNy species from the substrate during growth. However, CNx films produced by LE-IBAD are amorphous. The lack of FL structural features correlates with a lower degree of sp2 clustering, attributed to the promotion of nitrile groups. Therefore, low-energy ion bombardment is shown not to be a sufficient condition for the growth of FL-CNx. This result reinforces the eventual relevance of pre-formed CxNy species at the sputtering target in MS for the introduction and/or evolution of FL arrangements.
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| 5. |
- Music, Denis, et al.
(författare)
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Elastic modulus-density relationship for amorphous boron suboxide thin films
- 2003
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Ingår i: Applied Physics A. - : Springer Science and Business Media LLC. - 0947-8396 .- 1432-0630. ; 76:2, s. 269-271
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Tidskriftsartikel (refereegranskat)abstract
- Boron suboxide thin films nave been deposited on Si(100) substrates by reactive RF magnetron sputtering of a sintered B target in an Ar/O2 atmosphere. Elastic recoil detection analysis was applied to determine the film composition and density. Film structure was studied by X-ray diffraction and transmission electron microscopy. The elastic modulus, measured by nanoindentation, was found to decrease as the film density decreased. The relationship was affected by tuning the negative substrate bias potential and the substrate temperature during film growth. A decrease in film density, by a factor of 1.55, caused an elastic modulus reduction by a factor of 4.5, most likely due to formation of nano-pores containing Ar. It appears evident that the large scattering in the published data on elastic properties of films with identical chemical composition can readily be understood by density variations. These results are important for understanding the elastic properties of boron suboxide, but may also be qualitatively relevant for other B-based material systems.
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| 6. |
- Music, Denis, et al.
(författare)
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Elastic modulus of amorphous boron suboxide thin films studied by theoretical and experimental methods
- 2003
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 93:2, s. 940-944
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Tidskriftsartikel (refereegranskat)abstract
- Elastic modulus of amorphous boron suboxide thin films was studied by theoretical and experimental methods. It was shown that the increase of x in the a-BOx films from 0.08 to 0.18 decreased the magnitude of the elastic modulus from 273 to 231 GPa. The decrease of the elastic modulus with an increasing amount of O was correlated to the presence of the long B-O bonds with ionic contribution and the reduction of the film density.
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| 7. |
- Music, Denis, et al.
(författare)
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Quantum design and synthesis of a boron-oxygen-yttrium phase
- 2003
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 82:24, s. 4286-4288
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Tidskriftsartikel (refereegranskat)abstract
- A study was performed on quantum design and synthesis of a boron-oxygen-yttrium (BOY) phase. The calculations predicted that the BOY phase was 0.36 eV/atom more stable than crystalline BO0.17. The results showed that films with Y/B ratios ranging from 0.10 to 0.32, as determined via elastic recoil detection analysis, were grown over wide range of temperatures (300-600°C) and found to withstand 1000°C.
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| 8. |
- Rosen, Johanna, et al.
(författare)
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Effect of ion energy on structure and composition of cathodic arc deposited alumina thin films
- 2005
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Ingår i: Plasma chemistry and plasma processing. - : Springer Science Business Media. - 0272-4324 .- 1572-8986. ; 25:4, s. 303-317
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Tidskriftsartikel (refereegranskat)abstract
- The effect of energy supplied to the growing alumina film on the composition and structure has been investigated by varying substrate temperature and substrate bias potential. The constitution and composition were studied by X-ray diffraction and elastic recoil detection analysis, respectively. Increasing the substrate bias potential from -50 to -100 V caused the amorphous or weakly crystalline films to evolve into stoichiometric, crystalline films with a mixture of the alpha- and gamma-phase above 700 degrees C, and. gamma-phase dominated films at temperatures as low as 200 degrees C. All films had a grain size of less than 10 nm. The combined constitution and grain size data is consistent with previous work stating that. - alumina is thermodynamically stable at grain sizes less than 12 nm [McHale et al., Science 277, 788 ( 1997)]. In order to correlate phase formation with synthesis conditions, the plasma chemistry and ion energy distributions were measured at synthesis conditions. These results indicate that for a substrate bias potential of - 50V, ion energies in excess of 100 eV are attained, both from a high energy tail and the accelerated ions with charge greater than 1. These results are of importance for an increased understanding of the evolution of film composition and microstructure, also providing a pathway to. - alumina growth at temperatures as low as 200 degrees C.
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| 9. |
- Seppanen, T., et al.
(författare)
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Deviations from Vegard's rule in Al1-xInxN (0001) alloy thin films grown by magnetron sputter epitaxy
- 2007
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 101:4
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Tidskriftsartikel (refereegranskat)abstract
- Al1-xInxN (0001) thin films of the pseudobinary AlN-InN system were grown epitaxially onto (111)-oriented MgO wafers with seed layers of Ti1-y Zry N by dual direct current magnetron sputtering under ultrahigh vacuum conditions. The relaxed film c -axis lattice parameters determined by x-ray diffraction were studied as a function of composition in the range of 0.07
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