A study was made of the mismatch relaxation of 2 to 5nm thin elongated AlN islands formed during the growth of AlGaN on bulk m-plane GaN by molecular beam epitaxy. The relaxation of these m-plane AlN layers was anisotropic and occurred through the introduction of stacking faults in [00•1] planes during island coalescence, while no relaxation was observed along the perpendicular [11•0] direction. This anisotropy in the mismatch relaxation and the formation of stacking faults in the AlN islands were explained by the growth mode of the AlN platelets and their coalescence along the [00•1] direction.

Mismatch Relaxation by Stacking Fault Formation of AlN Islands in AlGaN/GaN Structures on m-Plane GaN Substrates. J.Smalc-Koziorowska, M.Sawicka, T.Remmele, C.Skierbiszewski, I.Grzegory, M.Albrecht: Applied Physics Letters, 2011, 99[6], 061901