改善氮化鎵系列薄膜特性以及LED元件之研究

Improvement of the GaN-based film quality and performance of LED

鄭士濠(Shih-Hao Cheng)

指導教授 ： 蘇炎坤

崑山科技大學/工程學院/電機工程研究所/碩士(2010年)

https://doi.org/10.6828/KSU.2010.00102

摘要

本論文，我們嘗試利用銀圍牆的方式包圍極性氮化鎵發光二極體四周，使得其側向光可被收集而不散逸，並且被迫導往正面方向，增加發光二極體正向光強度。此技術可使用在無法藉由封裝技術收集側向光的各式應用上，例如光電積體元件，或者生醫感測積體元件等等。最後結果，銀圍牆高度0.8 μm能夠提升LED元件正向光39%。 使用非極性氮化鎵能夠改善發光二極體的內部量子效率，但由於非極性氮化鎵薄膜結晶品質缺陷密度過高，針對非極性氮化鎵薄膜結晶品質研究的方法如缺陷選擇性蝕刻(DSE)可以顯示在r-軸藍寶石基板上成長a-軸非極性氮化鎵的表面缺陷，使用硫磷酸(3/1)可以觀察到非極性氮化鎵表面缺陷型態。最後使用單邊側壁橫向成長方式改善非極性氮化鎵結晶品質，能夠減少穿透差排(Threading dislocation)以及疊層缺陷(Stacking faults)密度。

關鍵字

氮化鎵 ； 發光二極體 ； 非極性

並列摘要

In this thesis, the silver enclosure around the polar GaN LED was used to couple the lateral light to the vertical direction and hence the light extraction efficiency in the vertical direction can be enhanced. This technique can be used on optoelectrical-integrated devices, or some biomedical-intergrated PDs application, which are hard to collect lateral light by using package technique. As a result, height of silver enclosure at 0.8um can effectively enhance the vertical light of LED about 39%.
Internal quantum efficiency of LEDs can be improved by using nonpolar GaN, but because the defect density of nonpolar GaN crystal is too high, research on nonpolar GaN thin film quality such as defect-selective etching(DSE) was conducted to reveal the surface defect of nonpolar a-plane GaN on sapphire substrate. In this experiment, mixed H2SO4 and H3PO4(H2SO4 : H3PO4 = 3:1) was used to observe the defect morphology of nonpolar GaN surface. And finally, one sidewall epitaxial lateral overgrowth(OSELOG), which can reduce TDs and SFs densities, was used to improve nonpolar GaN crystal quality.

並列關鍵字

GaN ； LED ； Non-polar

參考文獻

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