Aluminum Oxynitride-Engineered Transparent Aluminum Nitride Resistive Memory for Low-Leakage Multilevel Switching in Micro-LED Pixels

초록

Transparent micro light-emitting diode (LED) displays require driving elements that exhibit low off-state current, stable multilevel switching, and high optical transmittance. Oxide-based transparent resistive memories, however, undergo significant oxygen exchange with indium tin oxide (ITO) electrodes, which results in high leakage current and unstable switching windows. Nitride-based devices provide improved interfacial stability but typically show abrupt binary switching caused by deep nitrogen vacancy (VN) traps, limiting reliable multilevel operation. This study presents an aluminum nitride (AlN)-based transparent resistive memory incorporating a uniform ultrathin aluminum oxynitride (AlON) interfacial layer. By precisely controlling reactive sputtering conditions, oxygen incorporation at the ITO/AlN interface is regulated, forming a stable AlON transition layer that suppresses leakage pathways and introduces shallow, distributed traps. The device operates through Poole-Frenkel conduction, achieving reduced off-state current while enabling four reproducible resistance states suitable for grayscale modulation. The ITO/AlON/AlN0.81/ITO stack maintains similar to 79% optical transmittance in the blue spectral region, ensuring minimal loss during vertical integration with micro-LEDs. Temperature-dependent measurements confirm stable resistance separation under self-heating conditions. Integration with a micro-LED pixel demonstrates stepwise modulation of emission intensity without spectral distortion. These findings establish the AlON/AlN structure as an effective low-leakage, multilevel-capable driving element for transparent micro-LEDs.

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