Searching for Ge Clusters inside 3C-SiC Layers Grown by Vapor-Liquid-Solid Mechanism on 6H-SiC Substrates

Abstract

The use of Ge very rich Si-Ge liquid phase during the heteroepitaxial growth of 3C-SiC on Si-face, on-axis 6H-SiC(0001) substrate by vapour-liquid-solid mechanism leads to the formation of Ge based precipitates inside the 3C layer. These Ge based features are investigated by TEM and atomic models of the Ge clustering are proposed by means of high resolution TEM image simulation. Conventional TEM shows only a few small precipitates sparsely distributed near the interface, as well as dislocations and stacking faults starting from the interface in an almost regular manner. High resolution TEM shows fine structural imperfections in the form of Guinier Preston zones also near the interface. It is concluded that the high Ge content creates an enlargement of the SiC lattice leading to a misfit with the substrate. This could be the driving force for the formation of all the observed features.