The effect of ScN interlayer thickness on the defect density of (11•2) semipolar GaN grown on m-plane sapphire was studied by transmission electron microscopy. The interlayers comprised Sc metal deposited on a GaN seed-layer that was nitrided before GaN overgrowth by metal-organic vapour-phase epitaxy. Both interlayer thicknesses reduced the dislocation density by a factor of 100 to low-108/cm2. The 8.5nm interlayer produced regions that were free from basal plane stacking faults and dislocations. The overall BSF density here was reduced by a factor of 5, to 6.49 x 104/cm, without the need for an ex situ mask patterning step.

Defect Reduction in (11¯22) Semipolar GaN Grown on m-Plane Sapphire using ScN Interlayers. C.F.Johnston, M.A.Moram, M.J.Kappers, C.J.Humphreys: Applied Physics Letters, 2009, 94[16], 161109