Self-Assembled Size-Tunable Microlight-Emitting Diodes Using Multiple Sapphire Nanomembranes

Abstract

Microlight-emitting diode (Micro-LED) is the only display production technology capable of meeting the high-performance requirements of future screens. However, it has significant obstacles in commercialization due to etching loss and efficiency reduction caused by the singulation process, in addition to expensive costs and a significant amount of time spent on transfer. Herein, multiple-sapphire nanomembrane (MSNM) technology has been developed that enables the rapid transfer of arrays while producing micro-LEDs without the need for any singulation procedure. Individual micro-LEDs of tens of μm size were formed by the pendeo-epitaxy and coalescence of GaN grown on 2 μm width SNMs spaced with regular intervals. We have successfully fabricated micro-LEDs of different sizes including 20 × 20 μm², 40 × 40 μm², and 100 × 100 μm², utilizing the membrane design. It was confirmed that the 100 × 100 μm² micro-LED manufactured with MSNM technology not only relieved stress by 80.6% but also reduced threading dislocation density by 58.7% compared to the reference sample. It was proven that micro-LED arrays of varied chip sizes using MSNM were all transferred to the backplane. A vertical structure LED device could be fabricated using a 100 × 100 μm² micro-LED chip, and it was confirmed to have a low operation voltage. Our work suggests that the development of the MSNM technology is promising for the commercialization of micro-LED technology.