Low dislocation-density GaN layers were grown onto 6H–SiC(00▪1) substrates by molecular-beam epitaxy using high-density (~4 x 1011/cm2) self-assembled Stranski–Krastanov GaN nano-islands buffer. The density of dislocations determined from hot-wet chemical etching and atomic force microscopy showed that the insertion of coherent nano-islands as a buffer reduces the defect migration from the interface to the GaN epitaxial layers. The dislocation density was dramatically dropped to ~107/cm2 in GaN layers grown on coherent nano-islands as compared to ~109/cm2 in the typical GaN layers grown on the AlN buffer.

Reduction of Dislocations in GaN Epilayers using Templated Three-Dimensional Coherent Nano-Islands. K.Jeganathan, M.Shimizu, H.Okumura: Applied Physics Letters, 2005, 86[19], 191908 (3pp)