LED的技術發展目前主要往高發光效率、高可靠性、高散熱能力及薄型化四個方向，目前主要發展重點有GaN on silicon與高壓LED，GaN on silicon之所以引起越來越多的關注是因為它比傳統藍寶石基底LED的散熱能力更好，功率可以做的更大，且取得容易，成本低，但目前存在的問題是磊晶晶格不匹配造成良率過低，成本尚高。
而高壓LED因為其可大幅降低DC-DC的電壓降，進一步提升LED驅動電路的電源效率，可有效減少驅動電路產生的熱，降低LED燈具對散熱外殼的要求。
在製作高壓LED的過程中，製程相對於傳統低壓的LED複雜許多，尤其是在利用黃光製程製作內連線(Interconnection)之步驟中，我們面臨到漏電(leakage)、開路(open circuit)與電壓過高(V_f high issue)等問題。第一部份，我們製作的高壓LED藉由混合兩種鈍化層(passivation)解決了上述問題，在電流密度= 15A/cm2下將V_f從27.2降低至21.6。
第二部分，高壓LED相較於一般高功率(high power)LED也有較好的電流分布，我們比較了幾款不同電極分布(S1、S2、I1與I2)，得到一個較好的電極設計，同時亦做了1000小時的常溫壽命測試，比較電流分布對壽命衰減的影響。

The technique road map of LED (Light emitting diode) is for higher luminescent efficiency, reliability, heat dissipation and slimmer. The key techniques are GaN on silicon and HV-LED (high voltage). Better heat dissipation than sapphire based LED, GaN on silicon based LEDs catches more and more attention, which can be operated on higher power and accessible. But, by now, the Epitaxy problem of lattice mismatch between silicon and GaN lead to low yield, cost is not low enough. HV-LED can shrink the gap of DC to DC transformation voltage, improves driver’s efficiency. It can efficiently decrease the heat dissipates from driver, lessen the heat sink’s demand. When fabricates a HV-LED, the processes is more complex than conventional low voltage LED, especially on the photolithography for interconnection between die and die, we faced the problems like current leakage, open circuit and V_f high issue.
Part.1, we overcome the problems above mentioned by using two layer passivation. Under current density of 15A/cm2, we shrink the V_f from 27.2 to 21.6. Part.2, for an uniform current spreading. HV-LED’s current spreading is better than conventional high power LED, We design several electrode patterns to get a more uniform current spreading ,at the same time, we aging these types LED for 1000 hours under room temperature, compare the relationship between current spreading and the luminance’s decay.

1. S. Nakamura, M. Senoh, N. Iwasa, and S. Nagahama, Jpn. J. Appl.Phys.Part 34, L797 (1995)
2. S. Nakamura, T. Mokia, and M. Senoh, Appl. Phys. Lett. 64, 1689(1994).
3. 3. S. Nakamura, M. Senoh, S. Nagahama, N. Iwasa, T. Yamada, T.Matsushita,Y. Sugimoto, and H. Kiyodo, Appl. Phys. Lett. 70, 868(1996).
4. I. Akasaki, H. Amano, Y. Koide, K. Hiramatsu, and N. Sawaki. Journal of Crystal Growth, Vol. 98, pp. 209, 1989.
5. 參考 http://www.360doc.com/content/12/0725/13/713792_226364226.shtml
6. 參考 http://lights.ofweek.com/2012-09/ART-220018-8420-28643368.html
7. 施敏(S. M. Sze)著，半導體元件物理與製作技術，黃調元譯，二版，國立交通大學出版社，新竹，民國九十一年
8. S Nakamura. Japanese Journal of Applied Physics Part 2-Letters, Vol. 30, pp. L1705, 1991.
9. J.-F. Carlin and M. Ilegems. Appl. Phys. Lett. 83, 668(2003).
10. 參考 http://hyperphysics.phy-astr.gsu.edu/hbase/solids/pnjun.html
11. 參考 http://www1.gantep.edu.tr/~bgonul/dersnotlari/sc/
12. Nelson R. J. and Sobers R. G. Appl. Phys. Lett. 49, 6103 (1978b)
13. Franklin A. R. and Newman R. Appl. Phys. Lett. 84, 855(2004)
14. Krames M. R., Ochiai-Holcomb M., Höfler G. E., Carter-Coman C., Chen E. I., Tan I.-H., Grillot P.,Gardner N. F., Chui H. C., Huang J.-W., Stockman S. A., Kish F. A., Craford M. G., Tan T. S., Kocot, C. P., Hueschen M., Posselt J., Loh B., Sasser G., and Collins D. Appl. Phys. Lett. 75, 2365 (1999)
15. I. Schnitzer and E. Yablonovitch. Appl. Phys.Lett., vol. 63, pp. 2174–2176, 1993.
16. W. Schottky, “Semiconductor Theory of the Blocking Layer” (inGerman), Naturwissenschaften 26, 843, Dec. 1938; “On theSemiconductor Theory of Blocking and Point Contact Rectifiers”(inGerman), Z. Phy. 113, 367-414, July 1939; “Simplified and ExpandedTheory of Boundary Layer Rectifiers” (in German), Z. Phys. 118,539-592, Feb. 1942
17. J. S. Foresi and T. D. Moustakas. Appl. Phys. Lett. 62, 2859 (1993)
18. M. E. Lin, Z. Ma, F. Y. Huang, Z. F. Fan, L. H. Allen, and H. Morkoç. Appl. Phys. Lett. 64, 1003 (1994)
19. M. E. Lin, F. Y. Huang, and H. Morkoç. Appl. Phys. Lett. 64, 2557 (1994)
20. Dieter K. Schroder , “Semidonductor Material and DeviceCharacteruzation” , 2nd edition , p.143
21. G. H. B. Thompson, “Physics of Semiconductor Laser Devices ~Wiley,New York, 1980!, , ”p. 307.
22. F.M.Smits, “Measurement of sheet resistivities with the four point probe, ” Bell Syst. Tech. J, 1958
23. J. Szczyrbowski, A. Dietrich and K. Hartig. Sol. Energy. Mater. 19, 43 (1989).
24. E. Kusano, J. Kawaguchi, K. Enouji. J. Vac. Sci. Technol. A 4 (6)(1986) 2907.
25. Yoshiki Kato, Shota Kitamura, Kazumasa Hiramatsu. Journal of Crystal Growth.144,3(1994)
26. H Lorenzyz, M Despontxk, N Fahrniy, N LaBianca, P Renaudy and P Vettiger. J. Micromech. Microeng. 7 (1997) 121–124
27. H. Lorenz, M. Laudon, and P. Renaud. 41–42, 1998, 371–374
28. Nikolas Chronis and Luke P. Lee. IEEE, vol.14, issue 4
29. Chen Y, Wang Z L, Yin J S, Johnson D J and Prince R H. Chem. Phys. Lett. 272 178, 1999.
30. Tsai C L, Chen C F and Wu L K. Appl. Phys. Lett.81 721, 2002.
31. Z. Fan, S. N. Mohammad, W. Kim, O. Aktas, A. E. Botchkarev,and H.Morkoc﹐, Appl. Phys. Lett. 68, 1672 (1996)
32. S. J. Cai, R. Li, Y. L. Chen, L. Wong, W. G. Wu, S. G. Thomas,and K. L.Wang, Electron. Lett. 34,2354(1998)
33. CH Kuo, LC Chang, HM Chou. IEEE, vol.24, issue 7(2012)
34. X. Guo, Y. L. Li, and E. F. Schubert. Appl. Phys. Lett.,vol. 79, no. 13, pp. 1936–1938, 2001.
35. X. Guo and E. F. Schubert. J. Appl. Phys., vol. 90, no. 8,pp. 4191–4195, 2001.
36. D. W. Kim, H. Y. Lee, G. Y. Yeom, and Y. J. Sung. J. Appl. Phys.,vol. 98, no. 5, pp. 53 102–53 300, 2005.
37. N. Narendran, Y.Gu, J.P. Freyssinier, H. Yu, and L. Deng. Journal of Crystal Growth, Vol. 268, Issue 3-4, pp. 449-456, 2004.
38. Yimin Gu ; Nadarajah Narendran ; Jean Paul Freyssinier. SPIE, Volume 5530, 2004.