Thin-film vertical-type AlGaInP LEDs fabricated by epitaxial lift-off process via the patterned design of Cu substrate
Thin-film vertical-type AlGaInP LEDs fabricated by epitaxial lift-off process via the patterned design of Cu substrate
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DOI：
10.1364/oe.23.018156
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发表时间：
2015-07-13
期刊：
影响因子：
3.8
通讯作者：
Horng, Ray-Hua
中科院分区：
文献类型：
--
作者：
Wu, Fan-Lei;Ou, Sin-Liang;Horng, Ray-Hua
本研究在铜衬底上制备了薄膜垂直型AlGaInP发光二极管。通过执行外延剥离(ELO)工艺，LED器件可以从GaAs转移到Cu衬底上。然后对衬底进行分离，制作出ELO-LED。为了克服ELO过程中外延层产生裂纹的缺点，设计了各种图案化的铜衬底。并用有限元方法模拟了LED样品在电致发光过程中的应力分布。模拟结果表明，图案化铜衬底的最大应力可以限制在芯片边缘，并且在ELO过程中应力显著降低，从而明显减少了分离后的裂纹产生。该优化的图案化铜衬底被用于制作ELO-LED。此外，还采用了化学腐蚀工艺来刻蚀砷化镓衬底，将这种转移到铜衬底上的器件命名为CE-LED。在器件性能测试的基础上，CE-LED和ELO-LED的正向电压(@350 mA)分别为2.20和2.29 V，输出功率(@350 mA)分别为49.9和48.2 mW。此外，这两个样品的表面温度(@350 Ma)分别为46.9-48.3℃和45.2-47.0℃。显然，ELO-LED的器件特性与CE-LED非常相似。证实了图案化铜衬底的设计对获得薄膜垂直型AlGaInP发光二极管是非常有帮助的。此外，通过ELO工艺，分离的GaAs衬底可以重复使用，以降低生产成本。(C)2015年美国光学学会
In this study, the thin-film vertical-type AlGaInP LEDs on Cu substrates were fabricated. By performing the epitaxial lift-off (ELO) process, the LED device can be transferred from GaAs to Cu substrate. Then the GaAs substrate was separated and the ELO-LED was completed. To overcome the drawback of crack formation in the epilayer during the ELO process, various patterned Cu substrates were designed. Moreover, the finite element method was used to simulate the stress distribution in the LED sample during the ELO process. From the simulation results, an optimum structure of patterned Cu substrate was obtained since its maximum stress can be confined to the chip edges and the stress was decreased significantly during the ELO process, resulting in an apparent reduction of crack generation after separating the GaAs substrate. This optimum patterned Cu substrate was employed for the fabrication of ELO-LED. In addition, the chemical etching process was also used to etch the GaAs substrate, and this device transferred to Cu substrate was denoted as CE-LED. Based on the measurements of device performances, the forward voltages (@350 mA) of the CE-LED and ELO-LED were measured to be 2.20 and 2.29 V, while the output powers (@350 mA) of these two devices were 49.9 and 48.2 mW, respectively. Furthermore, the surface temperatures (@350 mA) of these two samples were 46.9-48.3 and 45.2-47.0 degrees C, respectively. Obviously, the device characteristics of the ELO-LED are very similar to those of the CE-LED. It confirms that the design of patterned Cu substrate is very helpful to obtain the thin-film vertical-type AlGaInP LEDs. Additionally, via the ELO process, the separated GaAs substrate can be reused for production cost down. (C) 2015 Optical Society of America