Optimizing Chip Sidewall Inclined Angle and Thickness for Enhanced Light Extraction Efficiency in AlGaN-based Deep Ultraviolet Micro-LEDs

In this paper, we systematically optimized the p-type layers thickness and sidewall inclined angle of flip-chip AlGaN-based deep ultraviolet Micro-LEDs using finite difference time-domain (FDTD) method, aiming to maximize light extraction efficiency (LEE). It was found that due to the reflection of electrodes, variation in the thickness of p-AlGaN and p-GaN causes oscillations in the light extraction efficiency, which is caused by destructive interference and constructive interference. Additionally, we found that a 40° sidewall inclination angle yields the maximum LEE, with a 40% enhancement over the vertical sidewall. These simulation results present potential avenues for improving the LEE of DUV Micro-LEDs.