WonTaeg Lim obtained a Ph.D. in physics from Hanyang University in South Korea and is currently a research director at Soft-Epi company. He is interested in micro-LEDs, and is conducting research on GaN-based epitaxy and chip characteristics. His main field of interest is the fabrication of full-color micro-LED displays utilizing vertically stacked GaN-based RGB epitaxy.
To make a next-generation ultra-high-resolution full-color micro-LED display, a vertical type monolithic epitaxy with RGB epi layers stacked on a single substrate is the key to success. Conventionally, a stacked epi structure was realized by growing RGB epitaxial layers on different substrates and then using a complex process of wafer bonding and removing the substrates. In this study, a monolithic RGB LED layer was manufactured by continuously growing RGB epi layers using an indium gallium nitride epitaxial technology. We introduce a method to grow each R, G and B epitaxial layer with independent PN junctions on a single substrate through one-time epitaxy. No needs of wafer bonding.