Fablication of AlN templates by high-temperature face-to-face annealing for deep UV LEDs

AlN templates fabricated via a combination of sputtering deposition and post-deposition high-temperature face-to-face annealing can be applied to deep-ultraviolet (DUV) light-emitting devices because of their extremely low threading dislocation density (TDD) despite their low-cost and simple fabrication process. First, this paper summarizes the overview and essential crystalline characteristics of the face-to-face annealed sputter-deposited AlN template (FFA Sp-AlN). Thereafter, recent progress in the TDD reduction of the FFA Sp-AlN and the metalorganic vapor phase epitaxy of AlN and Al x Ga1-x N on the FFA Sp-AlN have been reviewed. The TDD of approximately 4 x 10(7) cm(-2) was obtained on the sapphire substrates with an AlN film thickness of 1.2 mu m. Finally, the potential of the low-TDD FFA Sp-AlN has been discussed by demonstrating the performances of DUV light-emitting diodes fabricated on the FFA Sp-AlN.