Growth and Microstructure Analyses of Semipolar AlInN Epitaxial Layers on a Fully Relaxed Semipolar {112¯2} GaInN/GaN/m‐plane Sapphire Template

Abstract

Semipolar {} AlInN layers with thicknesses of ≈0.4 μm are grown on a fully relaxed semipolar Ga0.9In0.1N/GaN/m‐plane sapphire template by metalorganic chemical vapor deposition. The grown AlInN layers are confirmed to have relatively flat surfaces of less than 1.5 nm in root mean square roughness and high InN mole fractions ranging from 0.306 to 0.444, which are close to alloy compositions lattice matched to the underlying semipolar {} Ga0.9In0.1N layer. The microstructure analyses reveal that the AlInN layers are mostly relaxed for the underlying GaInN layer and have large fluctuations in lattice strains or lattice spacings, which might have caused many dislocations with different types from the basal‐plane stacking faults existing in the underlying GaN and GaInN layers. When compared to the growth of c‐plane AlInN layers, it is found that the InN incorporation rate into the AlInN alloys is enhanced using the semipolar {} GaInN template. Most noteworthy is that the relatively flat surfaces are realized for the semipolar AlInN layers despite their high InN mole fractions greater than 30%, submicrometer thickness, and many dislocations.