Papers by Author: L. Rapenne

Abstract: The development of 3C-SiC crystals from <0001> oriented hexagonal seed has always suffered from the systematic twinning which appears during the nucleation step of the layer. Using the continuous feed – Physical Vapour Transport (CF-PVT) growth process, we succeeded in growing single domain 3C-SiC crystals. To explain that, we propose in this work, a model based on the interaction between the lateral expansion anisotropy of 3C-SiC nuclei and the step flow growth front. Depending on the step edges direction, we can obtain one 3C orientation developing simultaneously with the vanishing of the other one. This model is confirmed by cross sectional HRTEM observation of the α-β interface.

Abstract: Because of the formation of DPB (Double Positioning Boundary) when starting from a hexagonal <0001> seed, DPB-free 3C-SiC single crystals have never been reported up to now. In a recent work we showed that, using adapted nucleation conditions, one could grow thick 3C-SiC single crystal almost free of DPB [1]. In this work we present the results of a multi-scale investigation of such crystals. Using birefringence microscopy, EBSD and HR-TEM, we find evidence of a continuous improvement of the crystal quality with increasing thickness in the most defected area, at the sample periphery. On the contrary, in the large DPB-free area, the SF density remains rather constant from the interface to the surface. The LTPL spectra collected at 5K on the upper part of samples present a nice resolution of multiple bound exciton features (up to m=5) which clearly shows the high (electronic) quality of our 3C-SiC material.