Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/4157
標題: 藉粗化視窗層提昇具高反射金屬基板之磷化鋁銦鎵發光二極體外部量子效率
Improvement of external quantum efficiency of AlGaInP-based LEDs by high reflective metal substrate and roughing window layer
作者: 李賜龍
Li, Szu-Lung
關鍵字: AlGaInP
磷化鋁銦鎵
LEDs
textured surface
electroplating
發光二極體
表面粗化
電鍍
出版社: 精密工程學系所
引用: [1] T. Gessmann and E. F. Schubert, “High-efficiency AlGaInP light-emitting diodes for soild-state lighting applications,” JOURNAL OF APPLIED PHYSICS, vol. 95, no. 5, p.p 2203-2216, 2004. [2] E. F. Schbert, Light-Emitting Diodes, Cambridge Uni. Press, 2006. [3] K. Kobayashi, S. Kawata, A. Gomyo, I. Hino and T. Suzuki, “Room-temperature cw operation of AlGaInP double-heterostructure visible lasers,” Electron Lett, vol. 21, no. 20, p.p 931-932, 1985. [4] Y. Ohba, M. Ishikawa, H. Sugawara, T. Yamamoto and Nakanisi, “Growth of high-quality InGaAlP epilayers by MOCVD using methyl metalorganics and their application to visible semiconductor lasers,” J. Cryst. Growth, vol. 77, p.p 374-379, 1986. [5] M. Iketa, K. Nakano, Y. Mori, K. Kaneko and N. Watanabe, “MOCVD growth of AlGaInP at atmospheric pressure using triethylmetals and phosphine,” J. Cryst. Grwoth, vol. 77, p.p 380-385, 1986. [6] C. P. Kuo, R. M. Fletcher, T. D. Osentowski, M. C. Lardizabel, M. G. Craford, and V. M. Robbins, “High performance AlGaInP visible light-emitting diodes,” Appl. Phys. Lett., vol. 57, no. 27, p.p 2937-2939, 1990. [7] R. M. Fletcher, C. Kuo, T. D. Osentowski and s V. M. Robbin, “Light-emitting diode with an electrically conductive window,” US Patent 5,008,718, 1991. [8] H. Sugawara, M. Ishikawa, Y. Kobubun, Y. Nishikawa and Naritsuka S., “Semiconductor light-emitting device,” US Patent 5,048,035, 1991. [9] K.H. Huang and T.P. Chen, “Light emitting-diode structure,” US Patent 5,661,742, 1997. [10] S. J. Chang, C. S. Chang, Y. K. Su, P. T. Chang, Y. R. Wu, K. H. Huang and T. P. Chen, “AlGaInP multiquantum well light-emitting diodes,” IEE Proc. Optoelectronics, vol. 144, p.p 1-2, 1997. [11] G. B. Stringfellow and M. G. Craford, “High Brightness Light-Emitting Diodes,” Academic Press, 1997. [12] M. R. Krames et al., “High-power truncated-inverted-pyramid (AlxGa1-x)0.5In0.5P/GaP ligh-emitting diodes exhibiting>50% external quantum efficiency,” Appl. Phys. Lett., vol. 75, no. 16, p.p 2365-2367, 1999. [13] 史光國,現代半導體發光及雷射二極體材料技術,全華科技圖書股份有限公司,2001。 [14] N. F. Gardner, H. C. Chui, E. I. Chen, M. R. Krames, J-W. Hung, F. A. Kish, S. A. Stockman, C. P. Kocot, T. S. Tan and N. Moll, “1.4× efficiency improment in transparent-substrate (AlxGa1-x)0.5In0.5P light-emitting diodes with thin (≦2000Å) active regions,” Appl. Phys. Lett., vol. 74, no. 15, p.p 2230-2232, 1999. [15] T. Baba, R. Watanabe, K. Asano, F. Koyama and K. Iga, “Theoretical and experumental estimations of photon recycling effect in ight emitting devices with metal mirror,” Jpn. J. Appl. Phys, vol. 35, p.p 97-100, 1996. [16] G. E. Höfler, D. A. Vanderwater, D.C. DeFevere, F. A. Kish, M. D. Camras, F. M. Steranka and I. H. Tan, “Wafer bonding of 50-nm diameter GaP to AlGaInP-GaP light-emitting diode wafers,” Appl. Phys. Lett., vol. 69, no. 6, p.p 803-805, 1996. [17] R. H. Horng, D. S. Wuu and S. C. Wei, “AlGaInP/AuBe/glass light-emitting diodes fabricated by wafer bonding technology,” Appl. Phys. Lett., vol. 75, no. 2, p.p 154-156, 1999. [18] E. H. Park et al., SPIE Proc, vol. 4641, no. 19, 2002. [19] H. W. Deckman and J. H. Dunsmuir, “Natural lithography,” Appl. Phys. Lett., vol. 41, no. 4, p.p 377-379, 1982. [20] I. Schnitzer, E. Yablonovitch, C. Caneau, T. J. Gmitter and A. Scherer, “30% external quantum efficiency from surface textured, thin-film light-emitting diodes,” Appl. Phys. Lett., vol. 63, no. 18, p.p 2174-2176, 1993. [21] A. Köck et al., Appl. Phys. Lett., vol. 57, no. 2327, 1990. [22] M. boroditsky, T. F. Krauss, R. Coccioli, R. Vrijen, R. Bhat and E. Yablonovitch, “Light extraction from optically pumbed light-emitting diode by thin-slab photonic crystals,” Appl. Phys. Lett., vol. 75, no. 8, p.p 1036-1038, 1999. [23] H. Y. Ryn et al., IEEE Selected topics in QE-8, 231, 2002. [24] M. R. Krames, O. B. Shchekin, R. M. Mach, G. O. Mueller, L. Zhou, G. Harbers and M. G. Craford, “Status and future of high-power light-emitting diodes for soid-state lighting,” Journal of display technology, vol. 3, no. 2, p.p 160-175, 2007. [25] LumiLeds, “Thermal management considerations for super flux LEDs,” Application Note 1149-4. [26] C. C. Lee and J. Park, “Temperature measurement of visble light-emitting diodes using nematic liquid crystal thermography with laser illumination,” IEEE photonics technology letters, vol. 16, p.p 1706-1708, 2004. [27] J. Millman and C. Halkias, Integrated Electronics, McGraw-Hill. [28] 真空技術與應用,行政院國家科學委員會精密儀器發展中心出版 [29] 楊智超, 高密度氯氣電漿應用於氮化鎵材料蝕刻製程之模型研究, 中原大學化學工程學系碩士論文,2002。 [30] V. Gottschalch , W. Heinig , E. Butter, H. Rosin and G. Freydank, “H3PO4 - etching of {001} faces of InP, (GaIn)P, GaP, and Ga(AsP),” Crystal research and technology, vol. 14, p.p 563-569, 2006. [31] 陳立俊,材料電子顯微鏡學,國家實驗研究院儀器科技研究中心出版,1990。 [32] 汪建民,材料分析,中國材料科學學會,1998。 [33] 梁永隆, 藉由視窗層粗化以提昇磷化鋁銦鎵發光二極體外部量子效率之研究, 中興大學精密工程研究所碩士論文, 2006. [34] 饒益侖, 以二次晶圓接合技術研製具金屬反射鏡面之p-side up高亮度磷化鋁銦鎵發光二極體, 中興大學精密工程研究所碩士論文, 2006.
摘要: 由於磷化鋁銦鎵(Aluminum Galium Indium Phosphide, AlGaInP) 與砷化鎵(Gallium Arsennide, GaAs)晶格常數匹配,一般而言,AlGaInP發光二極體(Light Emitting Diodes, LEDs)結構大多磊晶於GaAs基板。然而, GaAs能隙僅1.42 eV,且熱導不良(0.5 W/cm.K),不僅會吸收AlGaInP發出之光,亦會因LED接面所產生的熱無法有效移除,進而影響LED特性。 目前以金屬晶圓接合技術,將磊晶膜轉貼於散熱基板,移除GaAs基板,已解決上述問題,但此法所製之LEDs屬p-side down之結構,會犧牲以磷化鎵(Gallium Phosphide, GaP)作為良好窗口層之優點,另一方面若製作p-side up之LEDs,GaP位於LEDs磊晶結構頂層,其折射率(n = 3.5)與空氣折射率(n = 1)差異太大,易造成LEDs活性層所產生之光,於兩介質界面產生全反射之現象,大幅降低發光效率。 本論文將針對上述問題,提出一解決方法。將完成製作之LEDs,以聚苯乙烯(Polystyrene, PS)奈米小球作為GaP視窗層蝕刻遮罩,並以高密度電漿反應式離子蝕刻系統(Inductive Couple Plasma – Reactive Ion Etcher, ICP-RIE)進行蝕刻,或點狀陣列光阻搭配濕蝕刻,將GaP表面粗化,降低界面產生全反射之機率。最後以化學溶液,將GaAs基板、蝕刻停止層磷化銦鎵(Indium Gallium Phosphide, InGaP)與GaAs緩衝層移除,再以金作為反射鏡面(金對於波長為600 nm~700 nm之電磁波,反射率達95 %),並以此鏡面作為電鍍銅製程之種晶層,電鍍銅基板,利用硝酸水溶液蝕刻銅基板,完成元件製作。 由研究結果得知,以最佳條件粗化14 mil之LEDs,於20 mA之注入電流下,其正向光強度較未粗化之LEDs提昇約20 %。若將LEDs元件吸光層移除,蒸鍍金反射鏡面與電鍍銅基板,則可提高亮度約4倍。結合上述製程製作之LEDs,與以GaAs為基板之LEDs相比,則將亮度提升至4.5倍,光輸出功率由1.17 mW提昇到4.71 mW,發光效率由15.85 lm/W提昇至62.98 lm/W。此外,具散熱銅基板之LEDs,相較於以GaAs為基板之LEDs,在100 mA的注入電流下,接面溫度僅上升10oC。
In general, the lattice constant of AlGaInP is almost matched to GaAs substrate, so that the GaAs is used to be the substrate for AlGaInP epilayer growth. However, the band gap of GaAs is 1.42 eV and results in the most visibale-spectrum photons being absorbed. The lost light due to absorbtion effect is greater than 50%. Second, the thermal conductivity of GaAs is 56 W/m.K poor for releasing heat from the LEDs makes emission light shift to long wavelength, saturated and failure. Metal bonding is applied to transfer epilayer on high thermal conductivity substrate to solve these problems. But the LEDs structure is p-side down would sacrifice GaP as window layer. On the other hand, the refractive index of GaP (3.5) is larger than air (1). The total reflection is easy to take place on the interface reducing the intencity of light. This work will discuss how to solve these problems and increase the external quantum efficiency of LEDs. The accompolished LEDs apply PS nanosphere or PR dot arrays as masks on GaP etched by ICP-RIE or chemical solution. After etching, the textured GaP is going to reduce total reflection, then GaAs, InGaP and buffer GaAs are removed by chemical solution and coated gold by thermal evaporation system (The reflectivity of gold is about 95% versus the wavelength from 600 nm to 700 nm). Finally, the gold thin film also becomes a seed layer for Cu electroplating. In this study, the luminous intensity of 14 mil surface textured LEDs increases about 20% comparing with the original LEDs at 20 mA. If GaAs substrate was removed, Au mirror and Cu substrate were joined into the LEDs it could enhance the brightness about 4 times. Combining two processes, the luminous intensity of LEDs could get 4.5 times than that of the LEDs with GaAs substrate; output power could be also increased from 1.17 mW to 4.71 mW, the luminous efficiency was also increased from 15.85 lm/W to 62.98 lm/W. Futhermore, the junction temperature of LEDs just rise 10 oC in 100 mA injection current because of the Cu substrate providing well thermal disspation.
URI: http://hdl.handle.net/11455/4157
其他識別: U0005-2708200709581800
文章連結: http://www.airitilibrary.com/Publication/alDetailedMesh1?DocID=U0005-2708200709581800
Appears in Collections:精密工程研究所

文件中的檔案:

取得全文請前往華藝線上圖書館



Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.