Microstructure Study on Heterostructures of AlInGaN/GaN/Al₂O₃ by Using Rutherford ackscattering/Channelling and XRD

A quaternary AlInGaN layer is grown by metal--organic chemical vapour deposition on a sapphire (0001) substrate with a thick (>1μm) GaN intermediate layer. The compositions of In and Al are determined by Rutherford backscattering (RBS). The low ratio between the channelling yield and random yield according to the spectra of RBS/C (X_min=1.44%) means that the crystal quality of the AlInGaN film is perfect. The perpendicular and the parallel elastic strain of the AlInGaN layer, e^⊥=-0.15% and e^//=0.16%, respectively, are derived using a combination of XRD and RBS/channelling.