TEM investigation of the influence of the Ga-doping on the structure of 3C-SiC layers grown on 6H-SiC substrate by VLS mechanism

摘要

In present work we report on the study of microstructure and quality of 3C-SiC layers grown by Vapor-Liquid-Solid mechanism using Si-Ga melt on 6H-SiC substrates. We aim to investigate the influence of the Ga concentration in the SiGa melt on the density and type of structural defects appearing in the layers. Transmission Electron Microscopy study was carried out on 3C-SiC layers which were grown using three different Si_(50)Ga_(50), Si_(25)Ga_(75) and Si_(10)Ga_(90) melts. Main defects in the layers were microtwins and stacking faults. The microtwins were always formed at the interface with the 6H-SiC. By increasing the Ga concentration from 50% to 75% the stacking fault density is slightly increased, but the amount of microtwinned islands at the interface is much higher as compared to the layer grown in the lowest Ga content in the melt. Further increasing the Ga content deteriorates the quality of the layer in terms of stacking fault concentration. The defect density is rapidly increased and almost all of the stacking faults are lying on parallel lines at regular intervals between them.