A research team at Seoul National University (SNU) successfully grew a Micro LED array on a 100 nm-thick sapphire nano-membrane. The results were published on Scientific Reports on May 5, 2020.

According to the published paper, the team, led by Euijoon Yoon of the Department of Materials Science and Engineering of SNU, designed the sapphire nano-membrane array to grow an array of multi-faced Micro LEDs sized 4 μm × 16 μm. With the method, the Micro LED chip singulation does not need to go through plasma etching process, leading to a better external quantum efficiency (EQE).

(Image: Scientific Reports/SNU)

Compared to GaN formed on planar substrate, the new approach demonstrate a reduced Micro LED dislocation density by 59.6% and an improved internal quantum efficiency by 44%. Micro LEDs on sapphire nano-membranes also deliver 3.3 times higher photoluminescence.

In addition, since the thin (100nm) sapphire nano-membrane can be broken with mechanical force, Micro LEDs can be separated from the substrate and transferred to the display driving backplane more easily to simply the process and reduce cost.

This technology breakthrough is believed to accelerate the commercialization of Micro LED display technology as it overcomes the limitation of current Micro LED manufacture process.

The study was jointly conducted by researchers of SNU, Samsung Advanced Institute of Technology, KAIST, and Korea Photonics Institute with the support from Samsung Future Technology Promotion Center, Ministry of Education BK21 Plus Project and Korea Research Foundation.