| 1. |
- Baudin, M., et al.
(författare)
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Molecular dynamics simulations of an Al2O3(0001 +/-, 0-10(II))/CeO2 (011 +/-,01-1(II)) interface system
- 2001
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Ingår i: Thin Solid Films. - 0040-6090 .- 1879-2731. ; 401:02-jan, s. 159-164
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Tidskriftsartikel (refereegranskat)abstract
- Constant stress, constant temperature (10 K, 300 K) molecular dynamics simulations were carried out with shell-model potentials for an infinite composite ceria-alumina slab with two free surfaces [alpha -Al2O3 (0001) and CeO2(011) and their opposite counterparts]. The interface introduces considerable structural and dynamical changes, both at the slab surfaces and in the center of the slab. Structurally, both oxide surfaces become effectively oxygen-terminated and the surface structures become disordered close to the interface. Dynamically, in the region near the 'alumina surface/ceria surface/alumina-ceria interface' 3-phase junction the ionic motion is considerably enhanced. Thus, in the interface region, the ionic mean-square displacements increase 2-3 times compared to the pure slabs. Moreover, the ions at the interface participate in a new kind of motion, not present in the pure oxide slabs: large occasional, but frequently reoccurring, back-and-forth ionic motions take place with square-amplitudes as large as similar to0.70 Angstrom (2).
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| 2. |
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| 3. |
- Grivickas, V., et al.
(författare)
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Spatially and time-resolved infrared absorption for optical and electrical characterization of indirect band gap semiconductors
- 2000
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Ingår i: Thin Solid Films. - 0040-6090 .- 1879-2731. ; 364:02-jan, s. 181-185
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Tidskriftsartikel (refereegranskat)abstract
- The current status of the spatially and time-resolved free-carrier absorption (FCA) method is provided. The FCA technique allows monitoring carrier dynamics in a time scale from nanoseconds to miliseconds by employing either collinear or orthogonal geometry between pump and probe beams. A high spatial resolution is achieved allowing in-depth carrier profiles to be extracted. The method is particularly suited for investigation of injection-dependent optical and recombination phenomena: band gap optical absorption, Shockley-Read-Hall (SRH) lifetime, Auger recombination coefficient, and the injection-dependent surface (interface) recombination velocity. We summarize important aspects of the technique demonstrating numerous measurements that have been implemented in studies of bulk Si, epilaxial 4H-SiC and porous silicon.
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| 4. |
- Hammar, M., et al.
(författare)
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Investigation of chemically vapour deposited tungsten and tungsten silicide as contacts to n+ and p+ silicon areas
- 1990
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Ingår i: Thin Solid Films. - 0040-6090 .- 1879-2731. ; 185:1, s. 9-19
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Tidskriftsartikel (refereegranskat)abstract
- Tungsten and WSi2 have been examined as contact barriers between aluminium and n+ - or p+ -Si. The specific contact resistivity and diode leakage current were evaluated after heat treatment at different temperatures. Rutherford backscattering spectrometry measurements, X-ray diffraction analysis, scanning electron microscopy and sheet resistance measurements were performed to study the thermal stabilities of the Al/W/Si and Al/WSi2/Si systems. The contact resistivities of chemically vapour deposited tungsten and WSi2 to n+ -Si with a surface concentration of 7.5 × 1019 cm-3 were 8 × 10-7 Ωcm2 and 9 × 10-7 Ωcm2 respectively. To p+ -Si with a surface concentration of 2.6 × 1019 cm-3, they were 5 × 10-6 and 1 × 10-6 Ωcm2. Diffusion of aluminium was revealed to occur above 475°C in the case of tungsten and at 475°C in the case of WSi2. The void formation in silicon substrates was observed after heat treatment at 500°C for the Al/WSi2/Si system. The increase in leakage current for the Al/W/Si and Al/WSi2/Si structures is related to the onset of Si-Al interpenetration. Alloy formation was observed at 500°C for tungsten contacts whereas W-Al or other alloys were not detected up to 600°C for the WSi2 contact.
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| 5. |
- Hirschauer, B, et al.
(författare)
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Highly oriented alpha-alumina films grown by pulsed laser deposition
- 1997
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Ingår i: Thin Solid Films. - 0040-6090 .- 1879-2731. ; 305:1-2, s. 243-247
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Tidskriftsartikel (refereegranskat)abstract
- Highly oriented thin films of alpha-alumina have been grown by pulsed laser deposition on Si(lll). The influence of the substrate temperature on the film growth was studied by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (MID). Ablation at temperatures between room temperature and 850 degrees C gave rise to incorporated crystalline aluminium (Al), while the stoichiometric and highly oriented alpha-Al2O3 films were obtained only at 850 degrees C. The XRD rocking curve measurements of the ablated films showed the full-width-at-half-maximum (FWHM) Of 0.2 degrees. Further annealing at 1000 degrees C in air for 26 h slightly improved out-of-plane orientation. (C) 1997 Elsevier Science S.A.
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| 6. |
- Hirschauer, B, et al.
(författare)
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Studies of highly oriented CeO2 films grown on Si(111) by pulsed laser deposition
- 1999
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Ingår i: Thin Solid Films. - 0040-6090 .- 1879-2731. ; 348:1-2, s. 3-7
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Tidskriftsartikel (refereegranskat)abstract
- CeO2 is an interesting buffer layer material for the growth of YBa(2)Cu(3)O(7-)delta overlayers on Si in devices, with the aim of preventing heat-diffusion due to its excellent lattice matching with Si and YBa(2)Cu(3)O(7-)delta. Epitaxial CeO2-films have been synthesised on Si(lll) by pulsed laser deposition. Stoichiometric changes of the CexOy-film depending on the ambient oxygen pressure during the deposition were studied by X-ray photoelectron spectroscopy. A method is presented for growing a sharp interface between CeO2 and Si(111). The dependence of the inplane orientation of the CeO2 film on the substrate temperature was investigated by X-ray diffraction. The best films, grown at 700 degrees C, showed full width at half maximum of the rocking curve close to 0.1 degrees, but already at room temperature very highly oriented films with less than 0.2 degrees were synthesised. (C) 1999 Elsevier Science S,A. All rights reserved.
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| 7. |
- Lu, J., et al.
(författare)
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Chemical vapour deposition of molybdenum carbides : aspects of phase stability
- 2000
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Ingår i: Thin Solid Films. - 0040-6090 .- 1879-2731. ; 370:02-jan, s. 203-212
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Tidskriftsartikel (refereegranskat)abstract
- Thin films of different molybdenum carbides (delta-MoC1-x, gamma'-MoC1-x and Mo2C) have been deposited from a gas mixture of MoCl5/H-2/C2H4 at 800 degrees C by CVD. The H-2 content in the vapour has a strong influence on the phase composition and microstructure. Typically, high H-2 contents lead to the formation of nanocrystalline delta-MoC1-x films while coarse-grained gamma'-MoC1-x, is formed with an H-2-free gas mixture. This phase has previously only been synthesized by carburization of Mo in a CO atmosphere and it has therefore been considered as an oxycarbide phase stabilized by the presence of oxygen in the lattice. Our results, however, show that gamma'-MoC1-x films containing only trace amounts of oxygen can be deposited by CVD. Stability calculations using a FP-LMTO method confirmed that the gamma'-MoC1-x phase is stabilized by oxygen but that the difference in energy between e.g. delta-MoC0.75 and oxygen-free gamma'-MoC0.75 is Small enough to allow the synthesis of the latter phase in the absence of kinetic constraints. Annealing experiments of metastable delta-MoC1-x and gamma'-MoC1-x films showed two different reaction products suggesting that kinetic effects play an important role in the decomposition of these phases.
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| 9. |
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| 10. |
- Seger, Johan, et al.
(författare)
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Enhanced phase stability and morphological stability of Ni(Si,Ge) on strained Si0.8Ge0.2
- 2003
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Ingår i: Thin Solid Films. - 0040-6090 .- 1879-2731. ; 429:02-jan, s. 216-219
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Tidskriftsartikel (refereegranskat)abstract
- NiSi0.8Ge0.2 film formed on a strained Si0.8Ge0.2 layer epitaxially grown on a Si(100) substrate wafer is morphologically stable up to 750 degreesC. The NiSi0.8Ge0.2 film is found to be strongly oriented along its <010> direction. This remarkable stability is thus possibly caused by the tendency of an epitaxial alignment between the NiSi0.8Ge0.2 film and the Si0.8Ge0.2 layer. The presence of Ge in NiSi forming the ternary solution NiSi0.8Ge0.2 hinders the formation of NiSi2 even at 850 degreesC.
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