High-Brightness GaN-Based Blue Light-Emitting Diodes Using AlON Buffer Layer on 4 In.-Patterned Sapphire Substrate: Low-Dislocation-Defect Epitaxy, Growth Mechanisms, and Higher Device Performance

AlN is a common buffer layer in GaN-based light emitting diode (LED) devices. However, application of AlN on industry-relevant patterned sapphire substrate (PSS) causes unwanted screw dislocations in the epitaxial layer during GaN nucleation. Industry experience suggests that AlON buffer layer improves the quality of GaN epitaxial layer, but the low-dislocation-defect epitaxy mechanisms remain unclear. Herein, high-brightness GaN-based blue LEDs with the sputtered AlON buffer layer on industry-grade four-inch PSS is demonstrated. The effect of oxygen addition to AlN is revealed by growing GaN epitaxial layers on AlON buffer layers with different oxygen contents and testing these GaN layers in LED devices. Compared with conventional AlN, our AlON buffer layer reduces the density of screw dislocations, thereby improving the quality of the GaN epitaxial layers and the performance of GaN-based LEDs. These insights allow the explanation of the growth mechanisms of GaN on PSS with AlN and AlON buffer layers and can guide the development of next-generation optoelectronic technologies.