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dc.contributor.authorJhih-Yuan Jhengen_US
dc.identifier.citation[1] 呂紹旭, '光運雙月刊', No. 97, 2012年1月。 [2] 許世傑, '科學月刊', 2014年3月27日。 [3] L. Chuang, 'Optical Gain of strained wurtzite GaN quantum-well lasers,' IEEE Journal of Quantum Electronics, No. 32, p. 1791, 1996. [4] Z. Dridi, B. Bouhafs, P. Ruterana, 'First-principles investigation of lattice constants and bowing parameters in wurtzite AlxGa1−xN, InxGa1−xN and InxAl1−xN alloys,' Semiconductor Science Technology, Vol. 18, No. 9, p. 850, 2003. [5] A. Schmitz, A. Ping, M. Khan, Q. Chen, J. Yang, and I. Adesida, 'Metal contacts to n-type GaN,' Journal of Electronic Materials, Vol. 27, pp. 255-260, 1998. [6] D. Z. Bo, K. Wang, T. X. Chen, D. Chen, S. D. Yao,'Investigation on the formation mechanism and diffusion of the electrode metal of oxidized Au/Ni/p-GaN ohmic contact in different alloying time, ' Acta Physics Sinica, Vol. 57, No. 4, pp. 2445-2449, April 2008. [7] L. C. Chen, F. R. Chen, J. J. Kai, L. Chang, J. K. Ho, C. S. Jong, C. C. Chiu, C. N. Huang, C. Y. Chen, and K. K. Shih, 'Microstructural investigation of oxidized Ni/Au ohmic contact to p-type GaN,' Journal of Applied Physics, Vol. 86, No. 7, pp. 3826-3832, 1999. [8] B. A. Hull, S. E. Mohney, H. S. Venugopalan, and J. C. Ramer, 'Influence of oxygen on the activation of p-type GaN,' Applied Physics Letters, Vol. 76, No. 16, pp. 2271-2273, 2000. [9] L. C. Chen, J. K. Ho, C. S. Jong, C. C. Chiu, K. K. Shih, F. R. Chen, J. J. Kai, and L. Chang, 'Oxidized Ni/Pt and Ni/Au ohmic contacts to p-type GaN,' Solid-State Electronics, Vol. 76, No. 25, pp. 3703-3705, 2000. [10] X. A. Cao, E. B. Stokes, P. Sandvik, N. Taskar, J. Kretchmer, D. Walker, 'Optimization of current spreading metal layer for GaN/InGaN-based light emitting diodes,' Solid-State Electronics, Vol. 46, pp. 1235-1239, 2002. [11] H. Omiya, F. A. Ponce, H. Marui, S. Tanaka, and T. Mukai, 'Atomic arrangement at the interface in low-resistance contacts,' Applied Physics Letters, Vol. 85,No. 25, pp. 6143-6145, 2004. [12] W. J. Ho, W. Urbanek, M. C. Yoo, and J. L. Lee, 'Low-resistant and high-transparent Ru/Ni ohmic contact on p-type GaN,' Applied Physics Letters, Vol. 80, No. 16, pp. 2937-2939, 2002. [13] X. J. Li, D. G. Zhao, X. G. He, L. L. Wu, L. L. Yang, L. C. Le, P. Chen, Z. S. Liu, D. S. Jiang, 'Influence of different annealing temperature and atmosphere on the Ni/Au Ohmic contact to p-GaN,' Acta Physica Sinica, Vol. 62, No. 20, pp. 206801-1-206801-4, 2003. [14] D. Qiao, L. S. Yu, S. S. Lau, J. Y. Lin, H. X. Jiang, and T. E. Haynes, 'A study of the Au/Ni ohmic contact on p-GaN,' Journal of Applied Physics, Vol. 88, No. 7, pp. 4196-4200, 1999. [15] 施敏原著及張俊彥翻著, 半導體元件物理與製程技術(第三版), 台灣:高立圖書有限公司, 2000年, 頁192-206。 [16] E. Letts, T. Hashimoto, M. Ikari, and Y. Nojima, 'Development of GaN wafers for solid-state lighting via the ammonothermal method,' Journal of Crystal Growth, Vol. 350, pp. 66-68, 2012. [17] F. A. Kish, D. A. Vanderwater, D. C. DeFevere, D. A. Steigerwald, G. E. Hofler, K. G. Park, and F. M. Steranka, 'Highly reliable and efficient semiconductor wafer-bonded AlGaInP/GaP light-emitting diodes,' Electronics Letters, Vol. 32, pp. 132-134, 1996. [18] V. M. Bermudez, 'Study of oxygen chemisorption on the GaN(0001)-(1x1) surface,' Journal of Applied Physics, Vol. 80, pp. 1190-1200, 1996. [19] Z. L. Li, X. D. Hu, C. Ke, R. J. Nie, X. H. Luo, X. P. Zhang, T. J. Yu, B. Zhang, C. Song, Z. J. Yang, Z. Z. Chen, and G. Y. Zhang, 'Preparation of GaN-based cross-sectional TEM specimens by laser lift-off,' MICRON, Vol. 36, pp. 281-284, 2005. [20] 史光國,半導體發光二極體及固態照明(初版),台灣:全華,民國九十四年。 [21] H. Morkoc, 'Nitride Semiconductors and Devices,' Springer, pp. 196-197, 1999. [22] P. Nostell, A. Roos, and D. Ronnow, 'Single-beam integrating sphere spectrophotometer for reflectance and transmittance measurements versus angle of incidence in the solar wavelength range on diffuse and specular samples,' Review of Scientific Instruments, Vol. 70, p. 2481, 1999. [23] R. H. Horng, K. C. Shen, Y. W. Kuo and D. S. Wuu, 'Effects of Cell Distance on the Performance of GaN High-Voltage Light Emitting Diodes,' ECS Solid State Letters, Vol. 1, pp. 21-23, 2012. [24] X. J. Li, D. G. Zhao, D. S. Jiang, Z. S. Liu, P. Chen, J. J. Zhu, L. C. Le, J. Yang, X. G. He, S. M. Zhang, B. S. Zhang, J. P. Liu, and H. Yang, 'The significant effect of the thickness of Ni film on the performance of the Ni/Au Ohmic contact to p-GaN,' Journal of Applied Physics, Vol. 116, pp. 163708-1-163708-4, 2014. [25] Y. W. Zhang, S. Krishnamoorthy, F. Akyol, and S. Rajan, 'Quantum tunneling boosts UV LED efficiency,' Compound Semiconductor, p. 42, 2016.zh_TW
dc.description.abstract本實驗利用電子槍真空蒸鍍機在試片表面沉積厚度為10/5 nm的鎳/金電極,作為深紫外光發光二極體的P型電極,並藉由不同P型電極結構設計以改善深紫外光發光二極體的光電特性。由實驗結果得知,鎳/金電極厚度、退火溫度與退火時間的選擇對於鎳/金電極與p+GaN歐姆接觸的形成極為重要;鎳/金電極厚度的比例,退火溫度及時間也都會影響其特徵電阻值。本研究的最佳鎳/金電極厚度及退火參數為:鎳/金=10/5 nm、大氣氛圍下500 C退火10分鐘,在此製程條件下試片的特徵電阻值為:2.32×10-6 Ω-cm2。 本實驗設計四種不同P型電極結構的深紫外光發光二極體(3指狀電極、6指狀電極、9指狀電極以及12指狀電極之發光二極體),並且與傳統型之發光二極體做比較,最後再進一步製作9及12指狀電極之覆晶式發光二極體進行元件特性探討。因深紫外光發光二極體的歐姆接層(p+GaN)會吸收280 nm波長的光,此電極結構設計的目的即為增加電流擴散能力及光輸出功率。由實驗結果得知,9 指狀電極之發光二極體的電流擴散能力及光輸出功率較佳。在注入電流20 mA下,其光輸出功率及外部量子效率較傳統型之發光二極體,分別提升約150%、200 %;當注入電流為350 mA時,其光輸出功率及外部量子效率較傳統型之發光二極體,則分別提升約172 %、198 %。將9指狀電極之發光二極體製作成覆晶式後,在注入電流20 mA下,覆晶後之光輸出功率較覆晶前提升139%;在光電轉換效率及外部量子效率方面方面,分別較覆晶前提升約173 %、182 % ;當注入電流為350 mA時,覆晶後之光輸出功率較覆晶前提約92%;在光電轉換效率及外部量子效率方面,則分別較覆晶前提升約71%、79 %。由本研究結果得知,可藉由不同P型電極設計來提升深紫外光發光二極體的電流擴散能力及光輸出功率。zh_TW
dc.description.abstractIn this thesis, the Ni/Au (10/5 nm) films were grown on p+GaN layer by electron beam evaporation. The Ni/Au films were employed as a p-side electrode for the deep-ultraviolet light-emitting diodes (DUV-LEDs). Via the structural design of the p-side electrode, the optoelectronic performances of DUV-LEDs can be improved. Based on the experimental results, it can be found that the formation of an ohmic contact between Ni/Au and p+GaN are mainly affected by the thickness of Ni/Au and the parameters of annealing process for this p-side electrode (such as annealing temperature and annealing time). In this study, the most suitable thickness of Ni/Au electrode is 10/5 nm. Additionally, after annealing in air atmosphere at 500 C for 10 min, the ohmic contact characteristic between Ni/Au and p+GaN can be optimized, where its lowest specific contact resistivity reaches to 2.32×10-6 Ω-cm2. DUV-LEDs with four kinds of p-side electrode design (denoted as 3 fingers-LED, 6 fingers-LED, 9 fingers-LED, and 12 fingers-LED) were fabricated, and the conventional-LED was prepared as a contrasted sample. Besides, the 9 fingers-LED and 12 fingers-LED samples were further fabricated to flip-chip device. Because the emission light with a wavelength of 280 nm would be absorbed by the p+GaN layer, the purpose of this study is to improve the current spreading ability and the light output power of the LEDs through the p-side electrode design. The experimental results indicate that the 9 fingers-LED possessed better optoelectronic performances than those of the LEDs. At injection currents of 20 and 350 mA, the 9 fingers-LED exhibited 154% and 172% enhancements in the output power in comparison to those of conventional-LED, while the improvements in the external quantum efficiency (EQE) were 200% and 198%, respectively. After fabricating the flip chip device, the optoelectronic performances were further improved. At an injection current of 20 mA, the flip chip device possessed 139%, 173%, and 182% improvements in the output power, wall-plug efficiency, and EQE, respectively, as compared with those of 9 fingers-LED. Further increasing the injection current to 350 mA, the flip chip sample can achieve 92%, 71%, and 79% enhancements in the output power, wall-plug efficiency, and EQE, respectively, in comparison to those of 9 fingers-LED. These results clearly indicate that the p-side electrode design is useful for improving the optoelectronic performances of DUV-LEDs.en_US
dc.description.tableofcontents誌謝 i 摘要 ii Abstract iii 目錄 v 圖目錄 viii 表目錄 x 第一章 緒論 1 1-1 前言 1 1-2 研究動機 3 1-3 論文架構 3 第二章 理論基礎 5 2-1 發光二極體發光理論與氮化鋁鎵材料介紹 5 2-2 金屬-半導體接面理論 7 2-2-1 蕭特基能障原理 8 2-2-2 歐姆接觸之原理 9 2-3 電極材料性質及應用 10 2-3-1 鎳/金電極之應用 10 2-3-2 鎳/金電極與p-GaN形成歐姆接觸之機制 11 2-4 光電特性 12 2-5 發光二極體發光效率原理 12 2-5-1 內部量子效率(internal quantum efficiency, IQE) 13 2-5-2 光萃取效率(light extraction efficiency, LEE)及外部量子效率(external quantum efficiency, EQE) 13 2-6 發光二極體的基本特性參數 16 2-6-1 順向偏壓(forward voltage, Vf) 16 2-6-2 漏電流(leakage current, Ir) 16 2-6-3 光強度(luminance intensity, I) 16 2-6-4 輸出光功率(output power) 17 2-6-5 光電轉換效率(wall-plug efficiency, WPE) 17 2-6-6 傳輸線模型原理 17 第三章 實驗步驟 19 3-1前言 19 3-2 深紫外光氮化鎵試片之磊晶結構 19 3-3 電極備製 20 3-3-1 試片清洗 20 3-3-2 沉積鎳/金電極 20 3-4 深紫外光發光二極體元件製作 24 3-4-1 試片清洗 24 3-4-2 定義元件範圍 24 3-4-3 電極製作 25 3-4-4 元件切割 26 3-5 量測元件特性 28 3-5-1 光電特性量測 29 3-5-2 積分球量測系統 29 3-5-3 alpha-step量測系統 29 3-5-6 N&K光學量測系統 30 3-5-7 霍爾效應分析儀(Hall effect analyzer) 31 第四章結果與討論 32 4-1 改善鎳/金電極與p-GaN歐姆接觸之探討 32 4-1-1 不同鎳厚度對歐姆接觸之影響 32 4-1-2 不同金厚度對歐姆接觸之影響 34 4-2 退火參數及電極對深紫外光穿透率之探討 35 4-2-1 退火溫度對歐姆接觸之影響 35 4-2-2 退火時間對歐姆接觸之影響 36 4-2-3 N型電極之歐姆接觸 37 4-2-3 鎳/金電極對於深紫外光之穿透率 38 4-3 傳統型與3指狀電極之發光二極體光電特性探討 39 4-4 不同P型電極設計之發光二極體元件光電特性 41 4-4-1 元件之電流-電壓特性 41 4-4-2 光輸出功率 41 4-4-3 元件之光電轉換效率及外部量子效率 43 4-4-4 SpeCLED模擬電流擴散之分析 45 4-4-5 紅外線熱影像分析 46 4-4 P型電極設計應用在覆晶式發光二極體元件之探討 48 第五章 結論與未來展望 52 參考文獻 54   圖目錄 圖1-1近代照明系統及其發光效率之發展 1 圖2-1 LED 發光原理示意圖 5 圖2-2 AlxGa1-xN、InxGa1-xN、InxAl1-xN之能隙對成分含量圖 7 圖2-3 鎳/金與p-GaN形成歐姆接觸之機制示意圖 11 圖2-4三種不同光損失示意圖 15 圖2-5電阻與傳輸距離的曲線圖 18 圖3-1 深紫外光發光二極體之磊晶結構示意圖 19 圖3-2不同P型電極結構俯視圖 22 圖3-3 不同P型電極結構剖面示意圖 22 圖3-4 不同P型電極結構3D示意圖 23 圖3-4 水平式元件製作流程圖 27 圖 3-5 覆晶式元件製作流程圖 28 圖 3-5 (a)積分球基本工作原理 (a)積分球結構 (b)積分球原理 29 圖3-6 N&K analyzer工作原理與內部構造圖 31 圖4-1 CTLM製作流程圖與CTLM規格 33 圖4-2 不同鎳厚度對應之特徵電阻值 33 圖4-3 不同金厚度對應之特徵電阻值 34 圖4-4 不同退火溫度之電壓對電流曲線圖 35 圖4-5 不同退火時間對應之特徵電阻 36 圖 4-6大氣退火500°C、10分鐘之特徵電阻曲線圖 37 圖4-7 電壓對電流曲線圖 38 圖4-8 氮氣退火900°C、60秒之特徵電阻曲線圖 38 圖4-9 鎳/金電極穿透、反射光譜圖 39 圖 4-10 傳統型與3指狀電極之發光二極體電壓對電流曲線圖 40 圖4-11傳統型與3指狀電極之發光二極體電流對光輸出功率曲線圖 40 圖 4-12 不同P型電極結構之順向偏壓對電流特性曲線圖 41 圖4-13 元件點亮缺陷光發光圖 42 圖4-14 不同P型電極結構之光輸出功率對電流特性曲線圖 43 圖 4-15 不同P型電極結構之電激發光光譜圖 43 圖 4-16 不同P型電極結構元件之光電轉換效率 44 圖 4-17 不同P型電極結構元件之外部量子效率 45 圖 4-18 不同P型電極結構在20 mA下之電流擴散模擬圖 46 圖 4-19 不同P型電極結構在350 mA下之電流擴散模擬圖 46 圖4-20 為注入電流為20 mA時,不同P型電極結構之深紫外元件之IR紅外線表面溫度量測圖 47 圖4-21 為注入電流為350 mA時,不同P型電極結構之深紫外元件之IR紅外線表面溫度量測圖 48 圖4-22覆晶後之光輸出功率對電流比較曲線圖 49 圖4-23覆晶後之光電轉換效率對電流比較曲線圖 50 圖4-24覆晶後之外部量子效率對電流比較曲線圖 50 圖4-25光電轉換效率及外部量子效率之文獻比較 51   表目錄 表 1-1 紫外光發光二極體應用領域 2 表 4-1 鎳/金電極與p-GaN之特徵電阻值 35 表 4-2 特徵電阻之文獻比較 37 表 4-3 光輸出面積與光輸出功率整理表 43 表 4-4 注入電流為350 mA元件之最大、最小之表面溫度差 48zh_TW
dc.subjectdeep-ultraviolet light-emitting diodesen_US
dc.subjectp-side electrode designen_US
dc.subjectohmic contacten_US
dc.subjectexternal quantum efficiencyen_US
dc.titleImprovements of P-Electrode Design and Optical Output Power in Deep-Ultraviolet AlGaN LEDsen_US
dc.typethesis and dissertationen_US
item.openairetypethesis and dissertation-
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