Papers by Author: Jessica Eid

Abstract: We present a structural and optical investigation of nitrogen-doped single crystals of cubic silicon carbide prepared by the continuous feed - physical vapour transport method. Self-nucleated crystals were produced which exhibited well faceted square and triangular shapes. KOH etching was used to characterize the structural defects, like stacking faults and dislocations. The effect of changing the nitrogen flow rate on the different crystalline orientations was investigated by Raman spectroscopy and low temperature photoluminescence techniques.

Abstract: The conditions to succeed in growing 3C-SiC single crystals are first, make available large 3C-SiC seeds and second, develop a suitable growth process. In this paper, we will address those two issues by reviewing the most recent results in the field. Nucleation, growth, structural quality and doping results will be presented. New insights on 3C bulk growth will be discussed with respect to a future development of real bulk 3C-SiC ingots.

Abstract: We report the effect of changing the growth conditions in the case of bulk 3C-SiC crystals grown by the Travelling Zone Method when the seed is placed on the top graphite rod. First, we investigated the effect of changing the temperature gradient and the cooling ramp. Next we studied the effect of changing the seed polytype and misorientation. Every time, working in the 1700 °C temperature range, the grown polytype was 3C. From X-ray analysis we evidenced a better hetero-epitaxial relationship between the seed and layer when a low misorientation angle was used. Better quality and homogeneity were obtained on the first 500 .m of the layer and, beyond this thickness, micro-Raman measurements show that the effect of solvent (Si) incorporation is not yet fully under control.

Abstract: Cubic-silicon carbide crystals have been grown from solution by using the traveling-zone method. In this technique a molten silicon zone heated by induction coils is held between two rods of polycrystalline silicon carbide. Due to the growth set-up and boundary conditions, different mass transfer mechanisms are operative : diffusion, buoyancy, Marangoni convection and forced convection. The growth experiments have been performed on various seed crystals. Cubic SiC crystals were grown with a [111] habit on the [0001] silicon faces of 4H SiC seeds. The polytype 3C-SiC was identified by Transmission Electron Microscopy. Micro Raman spectroscopy and photoluminescence analyses showed good crystalline quality with few 6H inclusions.