A study was made of phase separation and stacking faults in InGaN which was grown onto sapphire substrates (with a GaN nucleation layer), or onto InGaN which was grown onto a thick GaN layer. At high In contents, the distribution of periodic stacking faults in InGaN which was grown onto sapphire substrates was detected by using selected-area diffraction and high-resolution transmission electron microscopy techniques. The periodic arrangement of stacking faults led to the formation of split spots, and the separation of the split spots corresponded to the distance between stacking faults. In the case of InGaN layers which were grown onto thick GaN layers, misfit strain was relaxed by the formation of V-grooves and random stacking faults. In the case of InGaN layers which were grown onto sapphire substrates with a thin buffer layer, a higher residual strain than that in the GaN/sapphire was found and was relaxed by the formation of periodic stacking faults in the InGaN layer.

Phase Separation and Stacking Fault of InGaN Layers Grown on Thick GaN and Sapphire Substrates by Metalorganic Chemical Vapour Deposition. H.K.Cho, J.Y.Lee, K.S.Kim, G.M.Yang: Journal of Crystal Growth, 2000, 220[3], 197-203