Papers by Author: Didier Chaussende

Abstract: High temperature solution growth of Al₄SiC₄ single crystals was carried out from the melt of silicon and aluminium pieces in a graphite crucible used as carbon source (typically 1800°C under 1 bar of argon). The obtained crystals, in the mm scale, were then characterized by a variety of techniques including: Raman spectroscopy, transmission electron microscopy techniques, X-ray diffraction and UV-Vis-NIR spectroscopy. A good structural quality was revealed by TEM, ensuring a well resolved Raman spectrum. The UV-Vis transmission spectrum shows an optical gap located around 2-2.5 eV.

Abstract: The growth process of silicon carbide crystals by physical vapor transport (PVT) on Si-face (0001) on-axis 6H-SiC substrates was analyzed. The growth rate was observed to be almost inversely proportional to the deposition pressure (R ∝ p-1) meaning that the growth rate is not limited by the number of growth spirals but by the vapor phase transport of the depositing species from the source to the sample surface. Analysis of the spiral step width shows an inverse square root dependence on the growth rate (y0 ∝ R-½). This experimental result is in accordance with the Burton, Cabrera and Frank theory and hence it can be concluded that there is no back-stress effect present.

Abstract: A top-down fabrication technique for nanometer scale silicon carbide (SiC) pillars has been demonstrated by using inductively coupled SF₆/O₂ plasma etching. At optimal etching conditions, the obtained SiC nanopillars exhibit high anisotropy features (aspect ratio ~ 6.5) with high etch depth (>7 μm). The etch characteristics of SiC nanopillars under these conditions show a high etch rate (550 nm/min) and a high selectivity (over 60 for Ni).