An Alternative X-ray Diffraction Analysis for Comprehensive Determination of Structural Properties in Compositionally Graded Strained AlGaN Epilayers

In this letter, a standard deviation based optimization technique has been applied on High Resolution X-ray Diffraction symmetric and asymmetric scan results to accurately determine the Aluminum molar fraction and lattice relaxation of Molecular Beam Epitaxy grown compositionally graded Aluminum Gallium Nitride (AlGaN)/Aluminum Nitride/Gallium Nitride (GaN) heterostructures. Mathews–Blakeslee critical thickness model has been applied in an alternative way to determine the partially relaxed AlGaN epilayer thicknesses. The coupling coefficient determination has been presented in a different perspective involving sample tilt method by offset between the asymmetric planes of GaN and AlGaN. Sample tilt is further increased to determine mosaic tilt ranging between 0.01° and 0.1°.