KAIST enables ultra-high resolution micro LED technology with 40% lower heat generation
– Demonstrates that epitaxial structure modification technology can fundamentally solve the problem of device efficiency degradation, and is expected to contribute significantly to the commercialization of ultra-high resolution micro LED displays.
[Professor Sanghyeon Kim, Doctoral Candidate Woo Jin Baek]
A team of researchers led by Professor Sanghyeon Kim has rediscovered the phenomenon that the efficiency of micro LEDs decreases when the device size is miniaturized to the size of a micrometer (μm, one millionth of a meter), and has shown that it can be fundamentally solved by changing the epitaxial structure.
Epitaxy technology is a process in which ultra-pure silicon or sapphire substrates, which are used as micro LEDs, are used as a medium and gallium nitride crystals, which are used as light emitters, are stacked on top of them.
Micro LEDs are being actively researched for their superior brightness, contrast, and lifespan compared to OLEDs, and Samsung Electronics commercialized a product with micro LEDs called “The Wall” in 2018, and Apple is expected to commercialize a product with micro LEDs in 2025.
To produce micro LEDs, the epitaxial structure grown on the wafer is cut into the shape of a cylinder or cuboid through an etching process to form pixels, which involves a plasma-based process.
However, these plasmas create defects on the sides of the pixels during the pixel formation process, and as the pixel size decreases and the resolution increases, the ratio of the surface area to the volume of the pixel increases, so the device side defects that occur during the process reduce the device efficiency of micro LEDs to a greater extent.
While much research has been focused on mitigating or eliminating side defects, these methods are limited by the fact that they require a post-processing step after the epitaxial structure is grown.
The researchers found that the current flowing through the sidewalls of micro-LEDs varies depending on the epitaxial structure during the operation of the micro-LED device, and based on this, they designed a structure that is insensitive to sidewall defects, solving the problem of decreasing efficiency as micro-LED devices miniaturize.
In addition, the proposed structure can reduce the heat generated when driving the display by about 40% compared to the existing one, which is significant for the commercialization of ultra-high resolution micro LED displays.
“This technology development has great significance in identifying the cause of efficiency decline, which has been a barrier to miniaturization of microLEDs, and solving it by designing an epitaxial structure, and is expected to be used for ultra-high resolution displays in the future,” said Professor Kim Sanghyeon.
[related press]
(worktoday) : ‘KAIST, 발열 40% 낮춘 초고해상도 마이크로 LED 기술 구현 – 워크투데이 (worktoday.co.kr)
(Chungcheong News) : KAIST, 발열 40% 낮춘 초고해상도 마이크로 LED 기술 구현 – 충청뉴스 (ccnnews.co.kr)
