Etching-free pixel definition in InGaN green micro-LEDs

Zhiyuan Liu; Yi Lu; Haicheng Cao; Glen Isaac Maciel Garcia; Tingang Liu; Xiao Tang; Na Xiao; Raul Aguileta Vazquez; Mingtao Nong; Xiaohang Li

doi:10.1038/s41377-024-01465-7

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Etching-free pixel definition in InGaN green micro-LEDs

Original Articles

- Etching-free pixel definition in InGaN green micro-LEDs
- Light: Science & Applications Vol. 13, Issue 8, Pages: 1655-1665(2024)
- Affiliations：
  
  Advanced Semiconductor Laboratory, Electrical and Computer Engineering Program, CEMSE Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia
- Author bio：
  
  Xiaohang Li (xiaohang.li@kaust.edu.sa)
- Funds：
- DOI：10.1038/s41377-024-01465-7
  CLC：
- Published：31 August 2024，
  
  Published Online：24 May 2024，
  
  Received：01 November 2023，
  
  Revised：31 March 2024，
  
  Accepted：24 April 2024
- Accepted：
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Liu, Z. Y. et al. Etching-free pixel definition in InGaN green micro-LEDs. Light: Science & Applications, 13, 1655-1665 (2024).
DOI：

Liu, Z. Y. et al. Etching-free pixel definition in InGaN green micro-LEDs. Light: Science & Applications, 13, 1655-1665 (2024). DOI： 10.1038/s41377-024-01465-7.

摘要

Abstract

The traditional plasma etching process for defining micro-LED pixels could lead to significant sidewall damage. Defects near sidewall regions act as non-radiative recombination centers and paths for current leakage

significantly deteriorating device performance. In this study

we demonstrated a novel selective thermal oxidation (STO) method that allowed pixel definition without undergoing plasma damage and subsequent dielectric passivation. Thermal annealing in ambient air oxidized and reshaped the LED structure

such as

-layers and InGaN/GaN multiple quantum wells. Simultaneously

the pixel areas beneath the pre-deposited SiO

layer were selectively and effectively protected. It was demonstrated that prolonged thermal annealing time enhanced the insulating properties of the oxide

significantly reducing LED leakage current. Furthermore

applying a thicker SiO

protective layer m

inimized device resistance and boosted device efficiency effectively. Utilizing the STO method

InGaN green micro-LED arrays with 50-

30-

and 10-µm pixel sizes were manufactured and characterized. The results indicated that after 4 h of air annealing and with a 3.5-μm SiO

protective layer

the 10-µm pixel array exhibited leakage currents density 1.2 × 10

−6

A/cm

at −10 V voltage and a peak on-wafer external quantum efficiency of ~6.48%. This work suggests that the STO method could become an effective approach for future micro-LED manufacturing to mitigate adverse LED efficiency size effects due to the plasma etching and improve device efficiency. Micro-LEDs fabricated through the STO method can be applied to micro-displays

visible light communication

and optical interconnect-based memories. Almost planar pixel geometry will provide more possibilities for the monolithic integration of driving circuits with micro-LEDs. Moreover

the STO method is not limited to micro-LED fabrication and can be extended to design other Ⅲ-nitride devices

such as photodetectors

laser diodes

high-electron-mobility transistors

and Schottky barrier diodes.

关键词

Keywords

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