Park, Sohyeon Kim, Taeseok Park, Sung Hyuk Kwon, Hee Ryeong Seo, Sung Jin Kulkarni, Mandar A. Ryu, Jung-El Park, Yongjo Ryu, Sang-Wan Kim, Seong Keun Jang, Ho Won 2025-08-20T07:07:33Z 2025-08-20T07:07:33Z 2025-08-20 2025-09 2050-7526 https://pubs.kist.re.kr/handle/201004/153002 High-performance micro-LEDs require transparent conductive oxides (TCOs) that exhibit excellent electrical and optical properties while remaining compatible with p-GaN. Various TCO deposition methods, including sputtering and e-beam evaporation, have been explored, each with its advantages and challenges. In this study, plasma-enhanced atomic layer deposition (PEALD) was employed to deposit tin-doped indium oxide (ITO) for micro-LED applications. To prevent plasma-induced damage, a bilayer structure was developed with a thin ALD indium oxide buffer layer beneath the PEALD ITO. The resulting ITO film, with a stoichiometry of In1.82Sn0.18O3 and a thickness of similar to 80 nm, exhibited a smooth surface (RMS roughness 0.49 nm), high optical transparency, and excellent conductivity. Post-deposition rapid thermal annealing promoted partial diffusion of the interfacial oxide layer into the ITO and p-GaN, and reduced hydrogen-related defect complexes located near the p-GaN interface. The optimized ITO layer was integrated into micro-LEDs of various sizes (150 x 150 mu m2 to 20 x 20 mu m2), demonstrating uniform electrical performance and low reverse leakage currents of 10-9 A. Long-term stability is confirmed through a constant voltage stress (CVS) conducted at 3.2 V for 76.5 hours. The conformal deposition capability of ALD enables precise and uniform coatings, highlighting its transformative potential in advancing TCO technologies for next-generation optoelectronic devices and high-efficiency displays. English Royal Society of Chemistry Conformal ALD of tin-doped indium oxide transparent p-ohmic contacts for micro- and nano-LEDs Article 10.1039/d5tc01462j 1 Journal of Materials Chemistry C, v.13, no.34, pp.17579 - 17587 Journal of Materials Chemistry C 13 34 17579 17587 N scie scopus 001540459600001 Materials Science, Multidisciplinary Physics, Applied Materials Science Physics Article ATOMIC LAYER DEPOSITION REFRACTIVE-INDEX PLASMA DAMAGE SOLAR-CELLS THIN-FILMS