Papers by Keyword: Hexagonal Voids

Abstract: A possible mechanism of hexagonal void movement during Physical vapor transport (PVT)-growth is proposed in terms of quasi-equilibrium phase transition process based upon the Si-C binary phase diagram. The hexagonal void movement can be realized when two different reactions occurs simultaneously: (1) SiC(s) solidification and (2) decomposition without graphitization. Further, the kinetic instability of the void movement observed is also discussed, and found to be explainable if the effect of the temperature gradient existing in the crystal grown in conventional PVT-process is included.

Abstract: 4H-SiC single crystals grown by the seeded physical vapour transport method have been investigated. These crystals were grown on 6H-SiC seeds. The influence of the seed temperature, form and granulation of SiC source materials on the stability and efficiency of the 4H polytype growth have been investigated. A new way of the seed mounting - with an open backside - has been used. Crystals obtained were free of structural defects in the form of hexagonal voids. The crystalline structure of SiC crystals was investigated by EBSD (Electron Backscatter Diffraction) and X-Ray diffraction methods. Moreover, defects in crystals and wafers cut from these crystals were examined by optical, scanning electron and atomic force microscopy combined with KOH etching.