Power Enhancement of 265 nm DUV-LED Flip-Chip by HVPE-AlN High-Temperature Annealing

In this paper, the X-ray diffraction full width at half the maximum (XRD FWHM) of a 3.5 µm-thick hydride vapor phase epitaxy-aluminum nitride (HVPE-AlN) (002) face after high-temperature annealing was reduced to 129 arcsec. The tensile strain in the HVPE-AlN samples gradually released with the increasing annealing temperature. When the annealing temperature exceeded 1700 °C, an aluminum oxynitride (AlON) region was generated at the contact interface between HVPE-AlN and sapphire, and the AlON structure was observed to conform to the characteristics of Al5O6N by high-resolution transmission electron microscopy (HRTEM). A 265 nm light-emitting diode (LED) based on an HVPE-AlN template annealed at 1700 °C achieved a light output power (LOP) of 4.48 mW at 50 mA, which was approximately 57% greater than that of the original sample.