| 1. |
- Chirita, V, et al.
(författare)
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Strain relaxation and thermal stability of the 3C-SiC(001)/Si(001) interface : A molecular dynamics study
- 1997
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Ingår i: Thin Solid Films. - 0040-6090. ; 294:1-2, s. 47-49
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Tidskriftsartikel (refereegranskat)abstract
- Molecular dynamics (MD) and high-resolution electron microscopy (HREM) imaging are used to investigate the mechanism of strain relaxation of a model 3C-SiC(001)/Si(001) interface. It is found that the essential atomic mechanism governing this process is the formation of undulations in planes parallel and perpendicular to the interface. The net effect is the generation of misfit-accommodating dislocations, of the [removed] type, which allow for structure relaxation at 2, 700 and 1000 K. MD configurations are then used for HREM image simulations. Comparisons with actual HREM images of the interface support the model interface and relaxation mechanisms proposed herein.
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| 2. |
- Krupin, OW, et al.
(författare)
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Ferrimagnetic 4f spin order in O/Gd surface monoxide
- 2003
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Ingår i: Thin Solid Films. - 0040-6090. ; 428:1-2, s. 98-101
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Tidskriftsartikel (refereegranskat)abstract
- The remanent 4f spin structure of the epitaxial surface monoxide O(1 X 1)/Gd(0001) has been investigated using magnetic dichroism in core-level photoemission (MDPE). Here we report the observation of a substantial dichroic signal of the chemically shifted Gd-4f PE line. It demonstrates the presence of a non-vanishing net magnetization of the surface monoxide layer at cryogenic temperatures. (C) 2002 Elsevier Science B.V. All rights reserved.
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| 3. |
- Oberg, K., et al.
(författare)
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Comparison of monolayer films of stearic acid and methyl stearate on an Al2O3 surface
- 2001
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Ingår i: Thin Solid Films. - : Elsevier. - 0040-6090. ; 397:1-2, s. 102-8
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Tidskriftsartikel (refereegranskat)abstract
- Both stearic acid and methyl stearate chemisorbs onto an oxide surface of aluminum with an asymmetric coordination of the carboxylate group as concluded from infrared (IR) spectroscopy data. Similarities in the IR spectra of the films from the two compounds suggest that the ester is bonded in the same way as the acid, and that the ester therefore undergoes hydrolysis during the surface reaction. X-Ray photoelectron spectroscopy (XPS) and IR data are interpreted in terms of self-assembled monolayer formation and a more dense film from the carboxylic acid in comparison with that from the ester. (C) 2001 Elsevier Science B.V. All rights reserved.
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| 4. |
- Selinder, T.I., et al.
(författare)
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Structural characterization of yttria (Y2O3) inclusions in YBa2Cu3O7−x films : Growth model and effect on critical current density
- 1993
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Ingår i: Thin Solid Films. - 0040-6090. ; 229:2, s. 237-248
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Tidskriftsartikel (refereegranskat)abstract
- A higher critical current and enhanced pinning was obtained in c-axis-oriented YBa2Cu3O7−x (YBCO)films having a higher density of semicoherent yttria (Y2O3) inclusions. The films were grown by sputtering and the inclusion density depends on the fraction of N2O in the sputtering gas. The inclusions were studied by transmission electron microscopy, both in planar sections and in cross-sections. They are embedded in the YBCO matrix without disturbing its structure appreciably, and the inclusion density is up to about 1017 cm−3, comprising about 4% of the film volume. From the appearance of moiré fringes and from high resolution transmission electron micrographs, it is concluded that the inclusions are highly oriented and have coherent or semicoherent interfaces towards matrix. A model for formation of the yttria inclusions during film growth is presented, which includes nucleation of epitaxial coherent yttria islands, layer-by-layer growth and finally overgrowth by advancing steps of the YBCO film. The enhanced pinning and transport critical current densities, relation to film microstructure and the possible flux-pinning mechanisms by these yttria inclusions are discussed.
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| 5. |
- Sjöström, H., et al.
(författare)
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Microstructure of amorphous C:H and metal-containing C:H films deposited on steel substrates
- 1993
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Ingår i: Thin Solid Films. - 0040-6090. ; 232:2, s. 169-179
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Tidskriftsartikel (refereegranskat)abstract
- Cross-sectional transmission electron microscopy (XTEM), including high-resolution microscopy (HREM), was employed to characterize the interface between different amorphous hydrogenated carbon (a-C:H) films and steel substrates. Additional analyses using Auger electron spectroscopy (AES) and X-ray diffraction (XRD) were also performed. Films were deposited both by high-energy (50 keV) nitrogen ion-beam decomposition of large hydrocarbon molecules and by magnetron plasma decomposition of C2H2 in mixed Ar-C2H2 discharges. The latter method was also used to deposit Mo- or W-containing a-C:H films (Me-C:H films) onto steel substrates with interlayers of the pure metals between the substrate and Me-C:H film. The films were found to be truly amorphous except for the cases of the metal-containing films, where 1–2 nm crystalline clusters were present in an a-C:H matrix. In the case of Mo the clusters were identified from HREM micrographs to have a bcc-like structure, characteristic of metallic Mo. The metal interlayers had a columnar microstructure with column widths of ∼ 30 nm. The interfaces between the Mo and W interlayers and the a-C:H films were found to extend over 20–40 nm with a gradual crystalline-to-amorphous transition. In most of the a-C:H film-substrate interface regions a thin layer ( < 10 nm) was observed which was predominantly amorphous but contained a small fraction of crystalline grains. AES showed an increase of both O and N close to the interface. However, for the cases with Mo and W interlayers, the substrate surface contaminants were less localized, and on some parts of the substrate surface the lattice fringes of the substrate and metal interlayer phase were continuous across a sharp interface.
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| 6. |
- Sjöström, H, et al.
(författare)
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Reactive magnetron sputter deposition of CNx films on Si(001) substrates : film growth, microstructure and mechanical properties
- 1994
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Ingår i: Thin Solid Films. - : Elsevier BV. - 0040-6090. ; 246:1-2, s. 103-109
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Tidskriftsartikel (refereegranskat)abstract
- There is currently considerable interest in producing new materials with extreme combinations of mechanical properties such as high hardnesses and moduli. One example of such a material is crystalline C3N4, which has been predicted to have a bulk modulus higher than that of diamond. In this paper we report on experiments carried out to synthesize CNx thin films. The films were grown in an unbalanced magnetron-sputtering system by reactive sputtering of C in N2 discharges. Si(001) substrates with the native oxide removed by thermal desorption and then kept at temperatures ranging from 150 to 600°C and substrate bias voltages Vs between 7.5 and -200 V were used. The films were analysed using X-ray diffraction, transmission electron microscopy (TEM). Auger electron spectroscopy, Rutherford backscattering and nano-indentation tests. Typically the films were grown at rates of 5 nm s-1 to total thicknesses of 300 nm. Owing to an extensive re-sputtering, only low negative bias voltages (-80
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| 7. |
- Rönnow, Daniel, et al.
(författare)
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Surface roughness of oxidised copper films studied by atomic force microscopy and spectroscopic light scattering
- 1998
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Ingår i: Thin Solid Films. - 0040-6090 .- 1879-2731. ; 325:1-2, s. 92-98
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Tidskriftsartikel (refereegranskat)abstract
- The interface roughness of Cu2O films produced by thermal oxidation of Cu was studied by spectroscopic elastic light scattering and atomic force microscopy. No correlation could be found between the roughness of the two interfaces, although the amplitude and the length scale of the roughness changed in the same way with film thickness for both interfaces. Both interfaces were found to have a fractal dimension of two. A first order perturbation theory was used to analyse the light scattering data; theory and experiment are in good agreement within the limits of the theory.
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| 8. |
- Abom, A.E., et al.
(författare)
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Influence of gate metal film growth parameters on the properties of gas sensitive field-effect devices
- 2002
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Ingår i: Thin Solid Films. - 0040-6090 .- 1879-2731. ; 409:2, s. 233-242
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Tidskriftsartikel (refereegranskat)abstract
- Thin films of Pt have been grown as gate metals on the oxide surface of gas sensitive field-effect devices. Both electron beam evaporation and dc magnetron sputtering has been used. The energy of the impinging Pt atoms, the substrate temperature and the thickness of the Pt film were used as parameters in this study. The influence of the growth parameters on the gas response has been investigated and compared with the properties of the films, studied by transmission electron microscopy, Auger electron spectroscopy, X-ray photoelectron spectroscopy and X-ray diffraction. The conditions during growth of the Pt film are found to have a large impact on the properties of the device. As expected, crystallinity, morphology and the metal/substrate interfacial structure are also affected by processing parameters. Three different growth processes stand out as the most promising from gas sensor considerations, namely room temperature evaporation, sputtering at high pressures and sputtering at high temperatures. The correlation between gas responses and properties of the gas sensitive layer is discussed. © 2002 Elsevier Science B.V. All rights reserved.
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| 9. |
- Almer, J, et al.
(författare)
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Microstructure, stress and mechanical properties of arc-evaporated Cr-C-N coatings
- 2001
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Ingår i: Thin Solid Films. - 0040-6090 .- 1879-2731. ; 385:1-2, s. 190-197
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Tidskriftsartikel (refereegranskat)abstract
- The relationships between coating microstructure and properties in the Cr-C-N system have been investigated as a function of composition and post-deposition annealing. Coatings of varying compositions were grown using arc-evaporation, by varying the reactive gas flow ratio fR = f(C2H4)/f(N2) from 0 to 0.2, and were found to consist primarily of the cubic d-Cr(C,N) phase. Changes in both the unstressed lattice parameter, ao, and X-ray diffraction background intensity indicate that both the carbon concentration within the d-phase and amorphous/crystalline content increases with fR. Increasing fR also decreases the magnitude of the compressive biaxial residual stress, from approximately 6 to 1 GPa, while increasing both the inhomogeneous stress and thermal stability. The elastic modulus and hardness of as-deposited coatings were determined from nanoindentation to be 320 and 23 GPa, respectively, for moderate carbon concentrations (fR=0.05). Concurrent variations in microstructure and hardness with post-deposition annealing indicate that the as-deposited hardness is significantly enhanced by the microstructure, primarily by lattice defects and related stresses (microstresses) rather than average stresses (macrostresses).
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| 10. |
- Almqvist, Nils, et al.
(författare)
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Roughness determination of plasma-modified surface layers with atomic force microscopy
- 1995
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Ingår i: Thin Solid Films. - 0040-6090 .- 1879-2731. ; 270:1-2, s. 426-430
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Tidskriftsartikel (refereegranskat)abstract
- Graphite surfaces exposed to the deuterium plasma in the TEXTOR tokamak were characterized in detail by means of scanning probe microscopy, ion beam analysis and colorimetry methods. The aim is to study the composition and structure of thin layer deposits formed on surfaces subjected to the tokamak plasma. The surface roughness was measured and parametrized in terms of fractal dimension and scaling constant. Several different methods for the fractal analysis of plasma-exposed surfaces have been critically evaluated. The main emphasis of this paper is on the correlation between surface roughness (fractal parameters), the amount of deposited atoms and the layer thickness.
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