Understanding of the Growth Mechanism Leading to Twin Boundary Elimination during 3C-SiC Heteroepitaxy on α-SiC Substrate by CVD

Abstract

Starting from the previously demonstrated twin-free 3C-SiC growth on 4H-SiC when using Ge pre-deposition treatment, this work focuses on the understanding of the growth mechanism that stands behind this result. Toward this end, short growth experiments were performed to allow the investigation of the nucleation stage. Based on the experimental observations, a mechanism is proposed which involves a Ge-induced transient homoepitaxial growth step followed by 3C nucleation when large terraces are formed by step faceting. Lateral expansion of the 3C islands leads to orientation selection and twin boundary elimination. Similar results can be obtained when applying a Si-based pre-deposition treatment so that the crucial transient homoepitaxial step is promoted in fact by the presence of a liquid phase itself, no by its chemical nature.