Microstructure of heteroepitaxial GaN grown on mesa-patterned 4H-SiC substrates

Cross-sectional transmission electron microscopy and atomic force microscopy have been used to study the microstructure of a thin heteroeptiaxial GaN film grown on (0001) 4H-SiC mesa surfaces with and without atomic scale steps. Analysis of a mesa that was completely free of atomic-scale surface steps prior to III–N film deposition showed that these GaN layers had a wide variation in island height (1–3μm) and included the presence of pit-like …