High-quality AlN/sapphire templates prepared by thermal cycle annealing for high-performance ultraviolet light-emitting diodes

Thermal cycle annealing (TCA) is introduced to accelerate the dislocation annihilation in sputter-deposited AlN films on sapphire. Compared with constant temperature annealing, AlN films processed by TCA showed lower dislocation densities, smoother surface morphology, and fewer defects generated from the AlN/sapphire interface. After optimizing the film thickness, AlN films with a thickness of 800 nm, and X-ray rocking curve full widths at half maximum of 10–20 arcsec (0002) and 80–90 arcsec (10-12) were demonstrated, providing a simple and low-cost way to prepare high-quality AlN/sapphire templates for high-performance ultraviolet light-emitting diodes.