Stepwise gradient etching for low-defect GaN Micro-LEDs with suppressed non-radiative recombination

Micro-light-emitting diode (Micro-LED) display technology demonstrates exceptional potential for next-generation intelligent displays, yet persistent challenges in luminescent efficiency degradation incurred by device miniaturization require urgent resolution. A stepwise gradient (SWG) etching process, proposed for device patterning to effectively suppress sidewall damage in Micro-LEDs, is comprehensively investigated for its impact on sidewall morphology and etching uniformity across varied processing conditions. This damage suppression mechanism significantly attenuates SRH non-radiative recombination and reverse leakage currents at the sidewall region, thereby enhancing external quantum efficiency. Furthermore, systematic analysis reveals how stepwise etching parameters modulate light emission distribution and photon extraction pathways, establishing a process-structure-performance relationship critical for Micro-LED.