Fabrication Strategy of GaN‐Based Micro LED with Ultra‐High‐Pixel‐Fidelity via Ar Ion Implantation and Wafer‐Scale Processes

ABSTRACT Micro‐light‐emitting diode (micro‐LED) displays with ultrahigh pixel density have garnered significant interest for near‐eye applications. However, as device dimensions decrease, pixel fidelity and efficiency decline due to sidewall damage from conventional mesa etching. In this work, a wafer‐scale high‐quality GaN epitaxial layer was grown on a sapphire substrate, exhibiting an ultralow threading dislocation density of 9.3 × 10 7 cm −2 and excellent wavelength uniformity (standard deviation of 1.40 nm). A high‐brightness and high‐pixel‐fidelity micro‐LED display was achieved using argon (Ar) ion implantation for pixel definition. Implantation parameters were optimized via finite‐element simulations to minimize lateral ion diffusion. By using photoresist as an implantation mask and employing flip‐chip bonding techniques, Micro‐LED arrays with a resolution of 3175 pixels per inch (1920 × 1080) were successfully fabricated. A single pixel exhibited a peak luminance exceeding 12 000 cd m − 2 and a maximum external quantum efficiency of approximately 7%. The proposed heterogeneous integration approach ensures excellent luminance uniformity and expands the color gamut, approaching the Rec. 2020 standard. Additionally, the effective emission area ratio exceeds 95%, with a linewidth deviation of merely 110 nm. This work demonstrates a promising strategy for mitigating pixel degradation in ultrahigh‐density micro‐LED displays while maintaining favorable optical performance.