The fabrication process and light extraction efficiency of AlGaInP-based flip-chip micro- light-emitting diode ( μ\mu -LED) array chips are improved by employing a wafer-bonding process, patterned metal contact, and sidewall passivation layers. The epilayers with indium tin oxide (ITO) can be successfully transferred from the GaAs substrate to the sapphire substrate and bound. Three types of patterned n-metal are employed in the μ\mu -LED as a self-aligning mask and light reflection layer, where the n-GaAs layer can be partially removed by the wet etching process. The dry etching process of MESA has been optimized by applying the BCl3 gas in the inductively coupled plasma (ICP) system, which can suppress the etching rate of the sidewall and improve the etching depth uniformity. Consequently, the leakage current of the μ\mu -LED array chip is decreased from 85 to 7 nA under the bias of −5 V. Moreover, three configurations of the metal contact/n-GaAs structures with Omnidirectional reflector (ODR) have been designed to reduce the emission light absorption, passivating the sidewall of MESA, and enhance the output power. Finally, the 0.52-in red μ\mu -LED array with a chip size of 100μm×100μm100\,\,\mu \text{m}\,\,\times 100\,\,\mu \text{m} and resolution of 138 pixels/in is realized when bonded with the drive IC. Consequently, the μ\mu -LED array chips with ODR and patterned contact show the highest external quantum efficiency of 51.1% and relative output power enhancement of 441% compared to the chip with SiO2 passivation layer and nonpatterned n-metal contact.

中文翻译：

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具有新颖像素结构的基于 AlGaInP 的高性能 Micro-LED 显示器


通过采用晶圆键合工艺、图案化金属接触和侧壁钝化层，改进了基于 AlGaInP 的倒装微型发光二极管 (μμ-LED) 阵列芯片的制造工艺和光提取效率。具有氧化铟锡（ITO）的外延层可以成功地从GaAs衬底转移到蓝宝石衬底并结合。 μμ-LED中采用了三种图案化的n-金属作为自对准掩模和光反射层，其中n-GaAs层可以通过湿法蚀刻工艺部分去除。通过在电感耦合等离子体（ICP）系统中应用BCl3气体，优化了MESA的干法刻蚀工艺，可以抑制侧壁的刻蚀速率，提高刻蚀深度均匀性。因此，在-5 V偏压下，μμ-LED阵列芯片的漏电流从85 nA降低到7 nA。此外，具有全向反射器（ODR）的金属接触/n-GaAs结构的三种配置已经被研究出来。旨在减少发射光吸收，钝化MESA侧壁，增强输出功率。最后是芯片尺寸为100μm×100μm100\,\,\mu \text{m}\,\,\times 100\,\,\mu \text{m}的0.52英寸红色μ\mu -LED阵列与驱动IC结合后可实现138像素/英寸的分辨率。因此，与具有SiO2钝化层和非图案化n金属接触的芯片相比，具有ODR和图案化接触的μμ-LED阵列芯片表现出最高的外量子效率51.1%和相对输出功率增强441%。