改善氧化銦錫薄膜及新式電極提升發光二極體亮度之研究

Study of LED Brightness Enhance by ITO Improved and Novel Electrode

張福文(Fu-Wen Chang)

指導教授 ： 孫台平

國立暨南國際大學/科技學院/光電科技碩士學位學程/碩士(2014年)

摘要

本論文主要目的是針對氮化鎵發光二極體在前段製程是否能利用新式反射式電極、透明導電層由不同蒸鍍方式沉積氧化銦錫薄膜的差異性做研究，利用元件製程方式的改變來探討發光二極體驅動電壓和發光效率是否能比傳統的發光二極體製造技術更佳優化。
在透明導電層部分，利用電子束蒸鍍（electron beam evaporation）、真空RF濺鍍設備(Sputter)分析兩種沉積薄膜後的光電特性，在波段450nm兩者的穿透率在高溫熱退火後皆能達到穿透率90%以上，片電阻值在濺鍍製程的條件下能有較低的阻值。
在電極部分由傳統發光二極體的Cr/Pt/Au改由新式反射電極Cr/Pt/Al/Ti/Au取代，新式電極的反射率比傳統電及提升48% ；最後結合濺鍍透明導電層跟新式電極應用在450nm~455nm的藍光發光二極體上，確實在元件、SMD封裝、To can測試分別能有效提升發光二極體的發光效率7~15%不等，也能有效降低發光二極體順向電壓3%。

關鍵字

氮化鎵 ； 電流分佈層 ； 反射式電極

並列摘要

In this study, thesis is to research the variations of the front end process of GaN based LED by use reflector electrode pad, transparent conductive layer and different deposition of ITO. Using element manufacture process to discuss if this change can improve the efficiency compare with traditional LED manufacture process.
At transparent conductive layer part, by using electron beam evaporation, and Sputter to analyze two different deposition based characteristics at wave 450nm, the rate of penetration can reach 90% after heat annealing, sheet resistance can has lower resistance unit by sputtering deposition.
At pad part, changing traditional LED pad Cr/Pt/Au into innovate reflector electrode pad Cr/Pt/Al/Ti/Au, the reflectance of innovate pad increase 48%. At last, combine TCL and innovate electrode pad on 450nm - 455nm blue ray LED, it indeed increase the luminous efficiency between 7-15%, also can decrease the forward voltage effectively 3%.

並列關鍵字

GaN ； current spreading layer ； reflective electrode

參考文獻

【1】S. Nakamura, S. Pearton, and G. Fasol, ”The Blue Laser Diode”, Springer-Verlag Berlin and Heidelberg GmbH & Co. K.

【2】T. Fujii, Y. Gao, R. Sharma, E. L. Hu, S. P. DenBaars and S. Nakamura,“Increase in the extraction efficiency of GaN-based light-emitting diodesvia surface roughening,” Appl. Phys. Lett., vol. 84, pp. 855, 2004.

【3】S. I. Na, G. Y. Ha, D. S. Han, S. S. Kim, J. Y. Kim, J. H. Lim, D. J. Kim, K.I. Min and S. J. Park , “Selective wet etching of p-GaN for efficientGaN-based light-emitting diodes,” IEEE Photon. Tech. Lett., vol. 18, pp.

【4】C. H. Kuo, C. C. Lin, S. J. Chang, Y. P. Hsu, J. M. Tsai, W. C. Lai and P. T.Wang, “Nitride-based light-emitting diodes with p-AlInGaN surfacelayers,” IEEE Electron. Dev. Lett., vol. 52, pp. 2346, 2005.

【5】J. K. Sheu, C.M.Tsai, M. L. Lee, S.C.Shei, and W.C.Lai, “InGaNlight-emitting diodes with naturally formed truncated micropyramids ontop surface,” Appl. Phys. Lett., vol. 88, pp. 113505, 2006.