Papers by Author: Jacques Rabier

Abstract: The 3C-6H polytypic transition in 3C-SiC single crystals is studied by means of diffuse X-ray scattering (DXS) coupled with transmission electron microscopy (TEM). TEM reveals that the partially transformed SiC crystals contain regions of significantly transformed SiC (characterized by a high density of stacking faults) co-existing with regions of pure 3C-SiC. The simulation of the diffuse intensity allows to determine both the volume fraction of transformed material and the transformation level within these regions. It is further shown that the evolution with time and temperature of the transition implies the multiplication and glide of partial dislocations, the kinetics of which are quantified by means of DXS.

Abstract: 4H-SiC intrinsic homoepitaxied single crystals have been nano indented at room temperature using a spherical indentor and the related deformation microstructures have been analyzed by Transmission Electron Microscopy. Dislocations are lying in the basal plane but have been found to be perfect, in contrast with observations made at higher temperature. Although such a change in deformation mechanism has been observed in other semiconductors such as Silicon and Indium Antimonide, it was unexpected in a very low stacking fault material such as SiC.

Abstract: Results of deformation experiments on 4H-SiC single crystals below the usual brittle to ductile transition temperature are reported and discussed in comparison of previous literature data. Si-core and C-core partials are evidenced in the basal plane, and perfect dislocations are also observed on other crystallographic planes. These results could indicate that dislocation activity under high stress is more complex than expected.