Defect reduction in (11-22) semipolar GaN grown on m-plane sapphire using ScN interlayers
Johnston, C F and Moram, M A and Kappers, M J and Humphreys, C J
The effect of ScN interlayer thickness on the defect density of (11-22) semipolar GaNgrown on m-plane sapphire was studied by transmission electron microscopy. The interlayers comprised Sc metal deposited on a GaN seedlayer that was nitrided before GaN overgrowth by metal-organic vapor-phase epitaxy. Both interlayer thicknesses reduced the dislocation density by a factor of 100 to low-10\^8 cm\^−2. The 8.5 nm interlayer produced regions that were free from basal plane stacking faults (BSF) and dislocations. The overall BSF density here was reduced by a factor of 5, to (6.49±0.07)×10\^4 cm−1, without the need for an ex situ mask patterning step.
Department of Materials
Imperial College London
Royal School of Mines
London, SW7 2AZ - UK