Silicon strained layers grown on GaP(001) by molecular beam epitaxy

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Structural Study of CoSi2/Si (001) and (111)

Nucleation and growth of CoSi2 films by thermal reaction of vapour deposited Co on (001) and (111) Si have been studied by transmission electron microscopy (TEM). On (001) Si, CoSi2 occurs in a number of orientations including the aligned (001) orientation. On (111) Si single crystalline layers are obtained, which are twin-oriented. In addition Si/CoSi2/Si structures have been formed by high-dose implantation of Co into (001) and (111) Si and subsequent annealing. In this way single crystalline ‘mesotaxial’ CoSi2 layers are obtained which are fully aligned with the Si-matrix. Epitaxial growth of CoSi2 on Si by conventional techniques (evaporation) and by high energy Co implantation is discussed

Microstructure of heteroepitaxial silicon/cobalt disilicide/silicon formed by cobalt implantation into (100) and (111) silicon

Heteroepitaxial Si/CoSi2/Si structures have been synthesized by high-dose implantation of Co into (100) and (111) Si at an energy of 170 keV and subsequent annealing. In the as-implanted state the implanted Co is found to be present as CoSi2. For a dose of 2×1017 Co/cm2, the Co is present in the form of epitaxial precipitates, which exhibit both the aligned (A-type) CoSi2 and twinned (B-type) orientation. For a higher dose of 3×1017 Co/cm2, a monocrystalline epitaxial CoSi2 layer near the top of the implanted Co distribution is formed during the implantation. The heteroepitaxial structures that are formed in this way are fully aligned. In contrast, when these structures are formed by sequential surface deposition techniques, twinning occurs at every Si/CoSi2 interface. The formation of the aligned orientation of the buried CoSi2 layer can be attributed to the larger stability of aligned precipitates as compared to twin-oriented precipitates

Copper Photodeposition on Titanium Dioxide Studied with HREM and EXAFS.

The possibility of direct selective surface activation by photodeposition of autocatalytic Cu particles on photosensitiveTiO2 substrates in an alkaline electroless copper solution has been investigated. The nucleation and growth of particleswere characterized by transmission electron microscopy (TEM). Ex situ high resolution TEM and in situ extendedx-ray absorption fine structure (EXAFS) spectroscopy were used to determine the oxidation state of photodeposited particleson thin polycrystalline TiO2 films and suspended TiO2 powders, respectively. It is shown that in the initial stages ofphotodeposition small

Surface analysis of reactive ion-etched indium phosphide

A dry-etch process for InP is developed using a mixture of Cl2, Ar, CH4, and H2. This process results in a high etch rate and good anisotropy. The induced damage is investigated by surface characterization after etching, using x-ray photoelectron spectroscopy, Rutherford backscattering spectrometry, photoluminescence measurements, and transmission electron microscopy. The etch mechanism is briefly discussed

Surface analysis of reactive ion-etched indium phosphide

A dry-etch process for InP is developed using a mixture of Cl2, Ar, CH4, and H2. This process results in a high etch rate and good anisotropy. The induced damage is investigated by surface characterization after etching, using x-ray photoelectron spectroscopy, Rutherford backscattering spectrometry, photoluminescence measurements, and transmission electron microscopy. The etch mechanism is briefly discussed

The adhesion of SiNx thin layers on silica-acrylate coated polymer substrates

Plasma Enhanced Chemical Vapor Deposition (PECVD) was used to grow 200, 300 and 400 nm thick silicon nitride layers (SiN x ) on a high temperature aromatic polyester substrate spin coated with a silica-acrylate hybrid coating (hard coat). Layers deposited without oxygen plasma treatment remained attached to the substrate, while spontaneous buckle delamination of the layer deposited with oxygen plasma treatment was observed directly after layer deposition. This effect was investigated using Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS), Atomic Force Microscopy (AFM) and Transmission Electron Microscopy (TEM). SIMS analyses showed a considerable increase of silicon oxide by exposing the substrate to oxygen plasma treatment, while AFM showed an increased roughness. Bright-field transmission electron micrographs show the presence of a particulate SiO2 layer. The oxygen plasma treatment thus removes the acrylate from the hard coat layer leaving behind the SiO2 particles leading to lower adhesion and thus to spontaneous buckle delamination. © 2009 Elsevier B.V. All rights reserved

Quantification of Liquid Crystal Concentrations in Periodically Stratified Polymer-Dispersed Liquid Crystal Films by Dynamic Secondary Ion Mass Spectrometry and Multivariate Statistical Analysis

Liquid crystal (LC) concentrations in stratified holographic polymer-dispersed liquid crystal (PDLC) films have been quantified from depth profiles obtained by time-of-flight secondary ion mass spectrometry (SIMS). The volatile nature of the LCs was hindered during SIMS analysis by capping the PDLC samples with poly(vinyl alcohol) and cooling to cryogenic temperatures. It remains difficult to gain quantitative results from SIMS analysis due to matrix effects yielding complex SIMS fingerprint spectra. With the multivariate statistical method discriminant function analysis the LC contents in the stratified holographic PDLC films were quantified. The concentration of the LC-rich layers was determined to be 32.9 ± 3.4 wt % LC, and for the polymer-rich layers it was 28.8 ± 2.7 wt % LC. The low concentration difference was supported by imaging analysis and modeling results

Characterization of polymer solar cells by TOF-SIMS depth profiling

Solar cells consisting of polymer layers sandwiched between a transparent electrode on glass and a metal top electrode are studied using dynamic time-of-flight secondary ion mass spectrometry (TOF-SIMS) in dual-beam mode. Because depth profiling of polymers and polymer-metal stacks is a relatively new field the craters were thoroughly studied by environmental SEM (ESEM), interferometry, surface profilometry and tapping mode AFM. A huge increase in crater bottom roughness was obsd. when starting from the aluminum top layer going in depth, resulting in a loss of depth resoln. layer-to-layer diffusion and contaminants at buried interfaces can be extd. from the depth profiles when taking into account the loss of depth resoln. [on SciFinder (R)

Precipitation of antimony delta-doping layers in Si studied with channeling Rutherford backscattering spectrometry

Antimony 5-doping layers in Si have been prepared using molecular beam epitaxy. First of all, a crystalline buffer layer was deposited at 700°C, followed by Sb deposition from a Knudsen cell. After cooling down to room temperature, amorphous Si was deposited on top and subsequently crystallized using solid phase epitaxy (SPE). The thermal stability of the 8-doping layers was studied in the temperature range of 625-725°C which is only slightly above the SPE temperature. Lateral Sb redistribution was followed by measurement of the Sb minimum yield in channeling Rutherford backscattering spectrometry. An increase in minimum yield was found and was correlated with the formation of precipitates as measured with transmission electron microscopy. The high diffusion coefficients required to explain the observed precipitation are qualitatively in agreement with a diffusion model, based on percolation theory, proposed before for Sb diffusion in heavily doped Si