Analysis of Vegard’s law for lattice matching InxAl1−xN to GaN by metalorganic chemical vapor deposition

Abstract Coherent In x Al 1−x N (x = 0.15 to x = 0.28) films were grown by metalorganic chemical vapor deposition on GaN templates to investigate if the films obey Vegard’s Law by comparing the film stress-thickness product from wafer curvature before and after In x Al 1−x N deposition. The In composition and film thickness were verified using atom probe tomography and high resolution X-ray diffraction, respectively. Ex-situ curvature measurements were performed to analyze the curvature before and after the In x Al 1−x N deposition. At ∼In 0.18 Al 0.82 N, no change in curvature was observed following InAlN deposition; confirming that films of this composition are latticed matched to GaN, obeying Vegard’s law. The relaxed a 0 - and c 0 - lattice parameters of In x Al 1−x N were experimentally determined and in agreement with lattice parameters predicted by Vegard’s law.