Homoepitaxy Growth of High-Quality AlN Film on MOCVD AlN Template by Hydride Vapor Phase Epitaxy

Herein, AlN film grown on metal-organic chemical vapor deposition (MOCVD) AlN template by high-temperature hydride vapor phase epitaxy (HVPE) is characterized. High-resolution X-ray diffraction results show that the crystal quality of the film is improved compared with that of the template. Atomic force microscopy shows that the root mean square roughness value also decreases. Cathodoluminescence spectra show that the main impurities in the epitaxial layer and template are oxygen atoms. Raman spectroscopy and geometric phase analysis show that HVPE AlN samples maintain a compressive stress internally, which is the key to inhibit film cracking. Transmission electron microscope characterization reveals that most of the dislocations at the interface inherit from MOCVD AlN template, incline in the subsequent growth, react with each other, and finally annihilate. The dislocation bending and reduction mechanism are demonstrated.