Surface Polarity Effects on the Hydride Vapor Phase Epitaxial Growth of GaN on 6H-SiC with a Chrome Nitride Buffer Layer

A CrN buffer layer was introduced to 6H-SiC substrate to aid the subsequent hydride vapor phase epitaxial growth of GaN. Crystallinities of GaN layers grown on both Si- and C-terminated surfaces of 6H-SiC wafers with and without CrN layers were compared. On Si-terminated SiC, CrN formed with a trigonal morphology, indicating a good crystallographic relationship with growth along the ⟨111⟩ axis. CrN formed randomly on C-terminated SiC, leading to the subsequent GaN growth occurring with no preferred orientation, suggesting deteriorated crystallinity. High-quality GaN layers were grown on the CrN buffered Si-terminated SiC.