Improved electrical properties of micro light-emitting diode displays by ion implantation technology

Generally, the inductively coupled plasma-reactive ion etching (ICP-RIE) mesa technology was used to remove p-GaN/MQWs and expose n-GaN for electrical contact in a fabricated micro light-emitting diode (mu LED). In this process, the exposed sidewalls were significantly damaged which result in small-sized mu LED presenting a strong size-dependent influence. Lower emission intensity was observed in the mu LED chip, which can be attributed to the effect of sidewall defect during etch processing. To reduce the non-radiative recombination, the ion implantation using an As+ source to substitute the ICP-RIE mesa process was introduced in this study. The ion implantation technology was used to isolate each chip to achieve the mesa process in the mu LED fabrication. Finally, the As+ implant energy was optimized at 40 keV, which exhibited excellent current-voltage characteristics, including low forward voltage (3.2 V @1 mA) and low leakage current (10(-9) A@- 5 V) of InGaN blue mu LEDs. The gradual multi-energy implantation process from 10 to 40 keV can further improve the electrical properties (3.1 V @1 mA) of mu LEDs, and the leakage current was also maintained at 10(-9) A@- 5 V.