Combined structural and optical studies of stacking faults in 4H-SiC layers grown by chemical vapour deposition

The formation of in-grown stacking faults (SFs) in chemical vapour deposition (CVD) grown 4H-SiC epilayer has been studied by high-resolution transmission electron microscopy (HRTEM) and low-temperature photoluminescence (LTPL). Local inhomogeneities in the SF density have been found, where different SF arrangements appear. They range from pure 8H-SiC unit cells to a few distinguished sequences, forming in some cases long-range semi-periodic incommensurate structures. Despite such large dispersion, the same optical (LTPL) signature is always found. This is discussed in the light of coupled quantum well models. [GRAPHICS] HRTEM image showing the formation of an extended defect (16 bilayers thick) in a CVD grown 4H-SiC epitaxial layer. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim