覆晶封裝技術為藍光發光二極體之主流技術，本論文以藍寶石基板之氮化鎵材料為主，開發覆晶式發光二極體製程技術為目的，可大幅提升氮化鎵發光二極體輸出功率與效率。
覆晶發光二極體必須達到低電阻與高反射率的P型歐姆接觸，所以在本論文中我們以Ni/Ag/Au的金屬組合作為P型氮化鎵電極，可達到良好的歐姆接觸，其特徵電阻可達到1.25E-5 Ω-cm2，在藍光波段中，使用Ni/Ag/Au的金屬組合其反射率可達80%左右。我們用此P型氮化鎵的金屬組合搭配覆晶封裝技術，成功製作出覆晶式發光二極體元件，能有效提升發光二極體輸出功率，與傳統式發光二極體相比較，可以提升2.5至3倍的輸出功率。

The flip-chip bonding technique is utilized widely in blue light-emitting diodes. The fabrication process for the GaN-based flip-chip light-emitting diodes on a sapphire substrate is proposed so that the output power and the efficiency of GaN lighting diodes are significantly enhanced. The flip-chip light-emitting diodes must achieve a low resistivity and high reflectivity p-type ohmic contact. The deployment of Ni/Ag/Au alloy shows a specific contact resistance as low as 1.25E-5 Ω-cm2. This Ni/Ag/Au alloy also provides the reflectivity as high as 80% optically in the blue light band.
By combining the p-type GaN metal contact with the flip-chip packing technique, a newly developed flip-chip bonded light-emitting diode is successfully demonstrated. The fabrication light-emitting diodes show an enhancement of at least of 250% in the extraction efficiency, compared to conventional light-emitting diodes.

[1] 財信出版社編著, LED投資新趨勢(初版), 財信出版有限公司, 2008.

[2] 史光國, 半導體發光二極體及固體照明, 全華科技圖書有限公司, 2005.

[3] Y. J. Lee, T. C. Lu, H. C. Kuo, and S.-C. Wang, “High Brightness GaN-Based Light-Emitting Diodes,” J. Displ. Technol., Vol. 3, No. 2, pp. 118-128, 2007.

[4] S. M. Pan, R. C. Tu, Y. M. Fan, R. C. Yeh, and J. T. Hsu, “Improvement of InGaN–GaN Light-Emitting Diodes with Surface-Textured Indium–Tin–OxideTransparent Ohmic Contacts,” IEEE Photon. Technol. Lett., Vol. 15, No. 5, pp. 649-651, 2003.

[5] H. Kim, K. H. Baik, J. Cho, K. K. Kim, S. N. Lee, C. Sone, Y. Park, and T. Y. Seong, “Enhanced Light Output of GaN-Based Light-Emitting Diodes by Using Omni Directional Sidewall Reflectors,” IEEE Photon. Technol. Lett., Vol. 19, No. 19, pp. 1562-1564, 2007.

[6] J. S. Lee, J. Lee, S. Kim, and H. Jeon, “GaN-Based Light-Emitting Diode Structure with Monolithically Integrated Sidewall Deflectors for Enhanced Surface Emission,” IEEE Photon. Technol. Lett., Vol. 18, No. 15, pp. 1588-1590, 2006.

[7] S. C. Hsu, C. Y. Lee, J. M. Hwang, J. Y. Su, D. S. Wuu, and R. H. Horng, “Enhanced Light Output in Roughened GaN-Based Light-Emitting Diodes Using Electrodeless Photoelectrochemical Etching,” IEEE Photon. Technol. Lett., Vol. 18, No. 23, pp. 2472-2474, 2006.

[8] J. J. Wierer, D. A. Steigerwald, M. R. Krames, J. J. O’Shea, M. J. Ludowise, G. Christenson, Y.-C. Shen, C. Lowery, P. S. Martin, S. Subramanya, W. Götz, N. F. Gardner, R. S. Kern, and S. A. Stockman, “High-power AlGaInN Flip-Chip Light-Emitting Diodes,” Appl. Phys. Lett., Vol. 78, No. 22, pp. 3379-3381, 2001.

[9] S. J. Chang, W. S. Chen, Y. C. Lin, C. S. Chang, T. K. Ko, Y. P. Hsu, C. F. Shen, J. M. Tsai, and S. C. Shei, “Nitride-Based Flip-Chip LEDs with Transparent Ohmic Contacts and Reflective Mirrors,” IEEE Trans. Adv. Package., Vol. 29, No. 3, pp. 403-408, 2006.

[10] W. K. Wang, D. S. Wuu, S. H. Lin, S. Y. Huang, P. Han, and R. H. Horng, “Characteristics of Flip-Chip InGaN-Based Light-Emitting Diodes on Patterned Sapphire Substrates,” Jpn. J. Appl. Phys., Vol. 45, No. 4B, pp. 3430–3432, 2006.

[11] C. F. Shen, S. J. Chang, W. S. Chen, T. K. Ko, C. T. Kuo, and S. C. Shei, “Nitride-Based High-Power Flip-Chip LED with Double-Side Patterned Sapphire Substrate,” IEEE Photon. Technol. Lett., Vol. 19, No. 10, pp. 780-782, 2007.

[12] E. F. Schubert, Light-Emitting Diodes., Cambridge University Press, Cambridge, U.K. 2003.

[13] 陳隆建, 發光二極體之原理與製程, 全華科技圖書有限公司, 2006.

[14] A. Motayed, R. Bathe, M. C. Wood, O. S. Diouf, R. D. Vispute, and S. N. Mohammad, “Electrical, Thermal, and Microstructural Characteristics of Ti/Al/Ti/Au Multilayer Ohmic Contacts to N-Type GaN,” J. Appl. Phys., Vol. 93, No. 2, pp. 1087-1094, 2003.

[15] C. T. Lee and H. W. Kao, “Long-Term Thermal Stability of Ti/Al/Pt/Au Ohmic Contacts to N-Type GaN,” Appl. Phys. Lett., Vol. 76, No. 17, pp. 2364-2366, 2000.

[16] Z. Fan, S. N. Mohammad, W. Kim, Ö. Aktas, A. E. Botchkarev, and H. Morkoç, “Very Low Resistance Multilayer Ohmic Contact to N-GaN,” Appl. Phys. Lett., Vol. 68, No. 12, pp. 1672-1674, 1996.

[17] E. F. Chor, D. Zhang, H. Gong, G. L. Chen, and T. Y. F. Liew, “Electrical Characterization and Metallurgical Analysis of Pd-Containing Multilayer Contacts on GaN,” Journal of Applied Physics, Vol. 90, No. 3, pp. 1242-1248, 2001.

[18] N. A. Papanicolaou, A. Edwards, M. V. Rao, J. Mittereder, and W. T. Anderson, “Cr/Al and Cr/Al/Ni/Au Ohmic Contacts to N-Type GaN,” J. Appl. Phys., Vol. 87, No. 1, pp. 380-386, 2000.

[19] J. K. Ho, C. S. Jong, C. C. Chiu, C. N. Huang, K. K. Shih, L. C. Chen, F. R. Chen, and J. J. Kai, “Low-Resistance Ohmic Contacts to P-Type GaN Achieved by the Oxidation of Ni/Au Films,” J. Appl. Phys., Vol. 86, No. 8, pp. 4491-4497, 1999.

[20] H. Ishikawa, S. Kobayashi, Y. Koide, S. Yamasaki, S. Nagai, J. Umezaki, M. Koike, and M Murakami, “Effects of Surface Treatments and Metal Work Functions on Electrical Properties at P-GaN/Metal Interfaces,” J. Appl. Phys., Vol. 81, No. 3, pp. 1315-1322, 1997.

[21] 方啟鑫, Low-Resistance Ohmic Contacts with High Reflectivity on P-Type GaN, 碩士論文, 中央大學, 2003.

[22] 李振道, Degradation for Ohmic Performance of Matel/Mg-Doped GaN, 碩士論文, 逢甲大學, 2004.

[23] J. K. Ho, C. S. Jong, C. C. Chiu, C. N. Huang, C. Y. Chen, and K. K. Shih, “Low-Resistance Ohmic Contacts to P-Type GaN,” Appl. Phys. Lett., Vol. 74, No. 9, pp. 1275-1277, 1999.

[24] B. Liu, E. Lambers, W. B. Alexander, and P. H. Holloway, “Effects of a Ni Cap Layer on Transparent Ni/Au Ohmic Contacts to P-GaN,” J. Vac. Sci. Technol., Vol. 20, No. 4, pp. 1394-1401, 2002.

[25] M. Koike, S. Nagai, S. Yamasaki, Y. Tezen, A. Kojima, and S. Iwayama, “GaN-Based MQW Light-Emitting Devices,” Proc. SPIE , Vol. 3938, pp. 24-29, 2000.

[26] S.Y. Kang, P.M. Williams, T.S. McLaren, Y .C. Lee, “Studies of Thermo Sonic Bonding for Flip-Chip Assembly,” Mater. Chem. Phys., vol. 42, pp. 31-37, 1995.