MICROSTRUCTURES DIAGRAM OF MAGNETRON SPUTTERED ALN DEPOSITS : AMORPHOUS AND NANOSTRUCTURED FILMS

International audienceIn order to get homogeneous nanostructured Aluminum Nitride deposits, thin films were grown at room temperature on [001] Si substrates by radio frequency magnetron reactive sputtering. The deposits were analysed by Transmission Electron Microscopy, energy dispersive X-ray spectroscopy and Auger electron spectroscopy. Their microstructure and chemical composition were studied versus the plasma working pressure and the radio frequency power. Systematic analysis of cross views of the films allowed the authors to draw a microstructure/process parameters map. Four microstructural types were distinguished according to the decrease of the deposition rate. One is the well-known columnar microstructure. The second one is made of interrupted columns or fibrous grains. The third one is made of nano-sized particles (size of the particles ranges from 1.7 to 8 nm). The fourth and last microstructure is amorphous. The "deposit morphology-process parameters" correlation is commented on

Photoluminescence properties of Er-doped AlN films prepared by magnetron sputtering

International audienceEr-doped aluminum nitride films, containing different Er concentrations, were obtained at room temperature by reactive radio frequency magnetron sputtering. The prepared samples show a nano-columnar microstructure and the size of the columns is dependent on the magnetron power. The Er-related photoluminescence (PL) was studied in relation with the temperature, the Er content and the microstructure. Steady-state PL, PL excitation spectroscopy and time-resolved PL were performed. Both visible and near infrared PL were obtained at room temperature for the as-deposited samples. It is demonstrated that the PL intensity reaches a maximum for an Er concentration equal to 1 at. % and that the PL efficiency is an increasing function of the magnetron power. Decay time measurements show the important role of defect related non radiative recombination, assumed to be correlated to the presence of grain boundaries. Moreover PL excitation results demonstrate that an indirect excitation of Er 3+ ions occurs for excitation wavelengths lower than 600 nm. It is also suggested that Er ions occupy at least two different sites in the AlN host matrix

Kinetics of the crystallization of icosahedral phase in ultra thin deposits of Al 62 Cu 25.5 Fe 12.5 alloy

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Auger electron microprobe analysis of the first steps of a Ni-20 Cr alloy oxidation

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Columnar growth of AlN by r.f.magnetron sputtering:Role of the {1 0 -1 3}planes

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Three-dimensional simulation of CVD diamond film growth

International audienceAs often reported in the case of CVD diamond synthesis, the elaboration conditions strongly affect the quality of the deposit interms of roughness, grain boundary quantity, structural defect density or non diamond phase insertion. It is recognised that this quality mainly depends of the texture evolution. To our knowledge, numerical simulations of this growth model that allow the diamond film quality to be predicted do not exist. In this way, we have developed a three-dimensional computer simulation of diamond growth. This numerical model is based on the homothetic growth of single diamond crystals in an Euclidean space and the selection of the enveloping surface obtained after the crystal interpenetration. By this way and in the limit of the exposed hypotheses, it is possible to build the topographies and to simulate its theoretical evolutions in the case of textured films synthesised on scratched silicon wafers according to the growth conditions such as the nucleation density, the growth rate ratio α = √3(V100/V111) or the synthesis time. We have particularly studied the ratio R{hkl} = (S{100}/S{100} + S{111}) of the topography according to the synthesis time, in order to follow the evolution of surface morphology

Calculation of thermal emissivity for thin films by a direct method

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