臺灣博碩士論文加值系統

在這篇論文裡，我們分別用兩種方法來改進將來的固態的照明設備︰氮化鎵發光二極體。為了進一步提升氮化鎵發光二極體的發光強度, 我們提出新穎的製程或磊晶過程。
對於氮化鎵發光二極體的研究，我們提出了藉由氫氧化鉀溶液濕式蝕刻製備具有粗糙側壁或具有空氣緩衝層的懸浮p型氮化鎵, 來分別提高元件表面或元件側壁的光取出率。經由濕式蝕刻製程後, 粗糙側壁會產生在特定的晶格方向上，製造出較傳統側壁更多的光散逸圓錐，因此，在多重量子井活化區內產生的光子能有更多機會藉由這些散逸圓錐而離開發光二極體內部,成為被取出的有效光源。這種濕式蝕刻製程所帶來的好處是，相較於傳統製程, 在短波長波段下, 發光強度約提昇7 ~8%, 而在長波長波段下亦能提昇約3 ~4%。 第二種方法是關於製備具有超晶格(superlattice, SL)的結構, 而此篇論文是將之安插在p型氮化鎵表層中或是介於p型氮化鎵與多重量子井間。 在這項研究過程中我們建立3 種類型的超晶格架構，分別是元件B( p-GaN / i-InGaN SL)， 元件C( i-GaN /p-InGaN SL) 和元件D (p-AlGaN / i-GaN SL), 和一種傳統, 未具有超晶格的結構(元件A)相比較。藉由元件B的實現 ,相較於傳統結構, 我們發現光輸出功率有較多正向幅度的改進。 而且，從測量漏電流的過程中，室溫下相較傳統架構, 元件B 將之降低了將近一百倍。 在此我們觀察了經由原子力顯微鏡所繪的元件表面起伏情況, 發現具有超晶格結構的元件表面較為平坦, 推論其改善的原因可能跟超晶格能阻絕由於基版與磊晶層晶格不匹配所造成的螺旋差排, 使元件表面缺陷減少有關. 另外,由電流-電壓特性曲線我們亦發現,具有超晶格結構之元件其導通電壓均較小且其表面特徵阻抗亦降低, 推論這些元件的表面濃度受到顯著提升,且在多重量子井層的長晶情況因為應力受到超晶格的控制而受到改善,故其導通電壓較小。

In this thesis, two approaches are presented to improve future solid-state lighting devices: GaN-based LEDs. All these approached are all related to how to promote the luminous intensity of nitride-based LEDs.
In respect of research on GaN-based LEDs, we have proposed oblique sidewalls and floating p-GaN with an air-buffer layer by using KOH wet-etching process to improve the light-extraction efficiency from device sidewalls and sample surface, respectively. The oblique sidewalls exist along specific directions, creating more escaped cones for output light than conventional ones, thus photons generating within MQW active region can experience multiple opportunities to escape from device sidewalls. With the benefit of wet-etching process, the luminous intensity was increased to nearly 7~8% at short-wavelength band and 3~4% at long-wavelength band compared with conventional process. The second approach is about the concept of modulation-doped superlattice(SL) structures inserted into p-GaN layer or between p-GaN and MQW. In this study we fabricate three kinds of superlattice structures, device B(with p-GaN/i-InGaN SL), device C(with i-GaN/p-InGaN SL), and device D(with p-AlGaN/i-GaN SL), compared with conventional structure, device A(without SL). Via the modification of SL structures, the external quantum efficiency(EQE) as well as the output power are both increased for p-GaN/i-InGaN SL structure and luminous intensity was increased to 127.6% and 113.5% for p-GaN/i-InGaN SL structure and i-GaN/p-InGaN SL structure , compared with the conventional structure, respectively. Moreover, from measuring the leakage currents, the leakage was significantly reduced by nearly two orders of magnitude for p-GaN/i-InGaN SL structure at room temperature. The enhancement can be attributed to the reduction of surface defects induced by threading dislocations which is cause by lattice mismatch between substrate and GaN epi-layer , due to the smoother surface morphology of the devices with SL structures observing from AFM images and better film quality of active layer speculating from small applied voltages of I-V curves .

Table of Contents
Abstract (in Chinese)……………………………………………………i
Abstract (in English)
Table Captions
Figure Captions

Chapter 1 Introduction 1
1-1 Investigational Backgrounds of GaN-based LEDs 1
1-2 A Brief History of GaN-based LED 3
1-3 Organization of this Thesis 4
Chapter 2 Investigations of Wet-Etching Processes in GaN-Based LEDs 6
2-1 A Previous Remark of Wet-Etching Process 6
2-2 GaN LEDs with Rough P-GaN Surface by Wet-Etching 7
2-2-1 A Brief Introduction of PEC Etching 7
2-2-2 Various Etching Solutions-using KOH solution 8
2-2-3 Various Etching Solutions-using solution 10
2-2-4 Summary 12
2-3 GaN LEDs with Rough Sidewalls and Floating P-GaN by Wet-Etching 13
2-3-1 Motivation 13
2-3-2 Experimental Details 15
2-3-3 Optical & Electrical Characteristics 19
2-3-4 Summary 20
Tables 22
Figures 23


Chapter 3 Investigations of Superlattice Structures in GaN-Based LEDs 49
3-1 Motivation and Physical Principles 49
3-2 Different Kinds of Superlattice Structures 51
3-3 Results and Discussions 52
3-3-1 Optical & Electrical Characteristics 52
3-3-2 Ideality Factors Analysis 54
3-3-3 AFM Measurement 56
3-4 Summary 56
Tables 58
Figures 60

Chapter 4 Conclusions & Prospects 71
4-1 Conclusions 71
4-2 Prospects 72
References 74

1.M. S. Shur, “GaN-based devices”, Electron Devices, vol. 63, pp. 115–118, 2005.

2.T. Yamamoto and K.Y. Hiroshi, “Materials design for the fabrication of low-resistivity p-type GaN using a codoping method,” Jpn. J. Appl. Phys., vol. 36, pp. L180~L183, 1997.

3.K.Y. Hiroshi, and T. Yamamoto, "Materials design of the codoping for the fabrication of low-resistivity p-type ZnSe and GaN by ab-initio electronic structure calculations," Phys. Stat. Sol., vol. 202, pp. 763-773, 1997.

4.T. Yamamoto, and K.Y. Hiroshi, “Electronic structures of p-type GaN codoped with Be or Mg as the acceptors and Si or O as the donor codopants,” Journal of crystal growth, vol. 189/190, pp. 532-536, 1998.

5.G. Kipshidze, V. Kuryatkov, B. Borisov, Y. Kuryavtsev, R. Asomoza, S. Nikishin, and H. Temkin, “Mg and O codoping in p-type GaN and AlxGa1–xN (0
6.T. Yamamoto, "Codoping method for solutions to doping problems in wide-band-gap semiconductors," Phys. Stat. Sol., vol. 193, pp.577-579, 2002.

7.O. Brandt, H. Yang, H. Kostial, and K. H. Ploog, “High p-type conductivity in cubic GaN/GaAs(113)A by using Be as the acceptor and O as the codopant,” Appl. Phys. Lett., vol. 69, pp. 199-202, 1996.

8.K.Y. Hiroshi, T. Nishimatsu, T. Yamamoto, and N. Orita, "Codoping method for the fabrication of low-resistivity wide band-gap semiconductors in p-type GaN, p-type AlN and n-type diamond: prediction versus experiment," J. Phys. Condens Matter, vol. 13, pp. 8901-8914, 2001.

9.R.Y. Korokov, J.M. Gregie, and B.W. Wessels, “Electrical properties of p-type GaN:Mg codoped with oxygen”, Appl. Phys. Lett., vol. 78, pp.2301-2304, 2001.

10.H. Katayama-Youshida, R.Kato, and T. Yamamoto, "New valence control and spin control method in GaN and AlN by codoping and transition atom doping," Journal of crystal growth, vol. 231, pp. 428-436, 2001.

11.R.Y. Korotkov, J.M. Gregie, and B.W. Wessels, “Electrical properties of oxygen doped GaN grown by metalorganic vapor phase epitaxy,” Opto-Electronics Review, vol. 10, pp.5430-5434, 2002.

12.S. D. Lester, F. A. Ponce, M.G. Craford and D. A. Steigerwald, ”High dislocation densities in high efficiency GaN-based light-emitting diodes ,” Appl. Phys. Lett., vol. 66, pp.772-775, 1995.

13.C.L. Wang, J.R. Gong, M.F. Yeh, B.J. Wu, W.T. Liao, T.Y. Lin, and C.K. Lin, “Improvement in the Characteristics of GaN-Based Light-Emitting Diodes by inserting AlGaN-GaN short-period superlattices in GaN underlayers,” IEEE Photonics Technology Letters, vol. 18, pp.312-315, 2006.

14.R. Huang, H. Dong, D. Wang, K. Chen, H. Ding, X. Wang, W. Li, J. Xu, and Z. Ma, ”Role of barrier layers in electroluminescence from SiN-based multilayer light-emitting devices,” Appl. Phys. Lett., vol. 92, pp. 181106, 2008.

15.K. N. Bourdakos, D. M. N. M. Dissanayake, T. Lutz, S. R. P. Silva, and R. J. Curry ,”Highly efficient near-infrared hybrid organic-inorganic nanocrystal electroluminescence device,” Appl. Phys. Lett., vol. 92, pp. 153311, 2008.

16.E. H. Park, I. T. Ferguson, S. K. Jeon, J. S. Park, and T. K. Yoo, ”The effect of silicon doping in the selected barrier on the electroluminescence of InGaN/GaN multiquantum well light emitting diode,” Appl. Phys. Lett., vol. 90, pp. 031102, 2007.

17.C. F. Huang, C. Y. Chen, C. F. Lu, and C. C. Yang, “Reduced injection current induced blueshift in an InGaN/GaN quantum-well light-emitting diode of prestrained growth,” Appl. Phys. Lett., vol. 91, pp. 051121, 2007.

18.M. S. Ferdous, X. Wang, M. N. Fairchild, and S. D. Hersee, “ Effect of threading defects on InGaN/GaN multiple quantum well light emitting diodes,” Appl. Phys. Lett., vol. 91, pp. 231107, 2007.

19.H. P. Maruska and J.J. Tietjen, “The preparation and properties of vapor-deposited single-crystal-line GaN,” Appl. Phys. Lett., vol. 15, pp. 327, 1969.

20.J. I. Pankov, E.A. Miller, D. Richman, J.E. Berkeyheiser, “Electroluminescence in GaN,” Journal of Luminescence, vol. 4, pp. 63-66, 1971.

21.H. P. Maruska, D.A. Stevenson, J. I. Pankov, “Violet luminescence of Mg-doped GaN,” Appl. Phys. Lett., vol. 22, pp.1003-1006, 1973.

22.H. Amano, M. Kito, K. Hiramatsu, I. Akasaki, “Effect of the structure of a photoactive compound on the dissolution inhibition effect,” Jpn. J. Appl. Phys., vol. 28, pp. L2112, 1989.

23.S. Nakamura, M. Kito, K. Hiramatsu, I.Akasaki, “Reducing reverse-bias current in 450°C-annealed n+p junction by hydrogen radical sintering,” Jan. J. Appl. Phys., vol. 34, pp. L797, 1995.

24.H. P. Maruska, ”A brief history of GaN blue light-emitting diodes,” http://www.sslighting.net/lightimes/features/maruska_blue_led_history.pdf

25.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 efficient GaN-based light-emitting diodes,” IEEE Photonics Technology Letter, vol. 18, pp.7709-7711, 2006.

26.J. L. Weyher, P. D. Brown, J. L. Rouviere, T. Wosinski, A. R.. Zauner, and I. Grzegory, “Recent advances in defect-selective etching of GaN,” Journal of Crystal Growth, vol. 210, pp. 151-156, 2000.

27.C. F. Lin, Z. J. Yang, J, H. Zheng, J. J. Dai, “Enhanced light output in nitride-based light-emitting diodes by roughening the mesa sidewall,” IEEE Photonics Technology Letters, vol. 17, pp. 2038-2040, 2005.

28.F. I. Lai, H. W. Huang, C. H. Chiu, C. F. Lai, T.C. Lu, H. C. Kuo, S. C. Wang, ”InGaN/GaN MQW nanorods LED fabricated by ICP-RIE and PEC oxidation processes,” Lasers and Electro-Optics, vol.10, pp. 1012-1013, 2007.

29.C. F. Lin, Z. J. Yang, J, H. Zheng, “Photoelectrochemical oxidation enhances optical output power in GaN -based light emitting diodes,” Lasers and Electro-Optics, vol. 8, pp. 4410-4412, 2005.
30.K. Yegin, L.W. Pearson, ”Experimental validation of electromagnetic edge waves on a PEC wedge,” IEEE Antennas and Propagation, vol. 51, pp 1578-1580, 2003.

31.T. Chiang, W. C. Chew, “A coupled PEC-TDS surface integral equation approach for electromagnetic scattering and radiation from composite metallic and thin dielectric objects”, IEEE Antennas and Propagation, vol. 54, pp. 337-339, 2006.

32.C. F. Wang, F. G. Hu, Y. B. Gan, ”Numerical modeling of the effect of cavity wall profile on interior scattering from large PEC cavity”, IEEE Antennas and Propagation, vol. 55, pp. 398-340, 2007.

33.F. I. Lai, C. C. Kao, C.F. Lin, H. C. Kuo, S. C. Wang, “Enhancement of light-output of GaN-based light-emitting diodes by bias-assisted photoelectrochemical oxidation of p-GaN in H2O,” Lasers and Electro-Optics, vol. 13, pp. 7665-7667, 2005.

34. Y. Morel, “Characteristic current decomposition for RCS analysis,” IEEE Antennas and Propagation Society International Symposium, vol. 3A, pp. 1998-2000, 2005.

35.K. Y. Hwang, “Development of nano-scale etching technique on GaN by CPAWE,” http://140.114.72.28/handle/987654321/7334, 2004.

36.Y. Z. Sheu, “The study of the etching and metal’s contact in GaN material,” Institute of Electro-Optical Science and Engineering, National Cheng Kung University, Tainan, Taiwan, ROC, 2004.

37.W. Schmid, “ Infrared light-emitting diodes with lateral outcoupling taper for high extraction efficiency,” Proc. SPIE, vol. 3621, pp.198-205, 1999.

38.S. J. Lee, S. W. Song, “Efficiency improvement on light-emitting diodes based on geometrically deformed chips,” Proc. SPIE, vol. 3621, pp.237-248, 1999.

39.C.S. Chang, S.J. Chang, Y.K. Su, C.T. Lee, Y.C. Lin, W.C. Lai, S. C. Chei, J. C. Ke, H.M. Lo, “Nitride-based LEDs with textured sidewalls,” IEEE Photon. Technol. Lett., vol.16, pp. 750-752, 2004.

40.M. R. Krames, M. O. Holcomb, G. E. Höfler, E. I. Chen, I. H. Tan, P. Grillot, N. F. Gardner, H. C. Chui, J. W. Huang, S. A. Stockman, F. A. Kish, and M. G. Craford, “High-power truncated-inverted-pyramid (AlxGa1–x)0.5In0.5P/GaP light-emitting diodes exhibiting >50 external quantum efficiency,” Appl. Phys. Lett., vol. 75, pp. 2365, 1999.

41.D. Eisert, V. Härle, “Simulations in the developement process of GaN-based LEDs and laser diodes,” International Conference on Numerical Simulation of Semiconductor Optoelectronic Devices, vol. 21, pp.1012-1014, 2002.

42.C. C. Kao, H. C. Kuo, H. W. Huang, J. T. Chu, Y. C. Peng, Y. L. Hsieh, C. Y. Luo, S. C. Wang, C. C. Yu, and C. F. Lin, “Lighting-output enhancement in a nitride-based light-emitting diode with 22°undercut sidewalls”, IEEE Photonics Technology Letters, vol. 17, pp.19-21, 2005.

43.M. Itoh, T. Kinoshita, C. Koike, M. Takeuchi, K. KAWASAKI and Y. Aoyagi, “Straight and smooth etching of GaN plane by combination of reactive ion etching techniques ”, Japanese Journal of Applied Physics, vol.45, pp. 3988-3991, 2006.

44.J.R. Mileham, S.J. Pearton, C.R. Abernathy, and J.D. Mackenzie, “Patterning of AlN, InN, and GaN in KOH based solutions,” J. Vac. Sci. Technol., vol. A14, pp. 836~839, 1995.

45.T. S. Choy, J. Chen, S. Hershfield, ”A superlattice effect in the resistivity of multilayers,” IEEE Magnetics, vol. 34, pp. 933–935, 1998,

46.C. L. Wang, J. R. Gong, M. F. Yeh, B. J. Wu, W. T. Liao, T. Y. Lin, C. K. Lin, “Improvement in the characteristics of GaN-based light-emitting diodes by inserting AlGaN-GaN short-period superlattices in GaN underlayers,” IEEE Photonics Technology Letters, vol. 18, pp. 1497–1499, 2006.

47.M. Jain, H. Appel, A. Meier, W. Wegscheider, K. F. Renk, ”Semiconductor-superlattice oscillator with superlattices connected in parallel and series as active elements for generation of millimetre waves,” IEE Microwaves, Antennas and Propagation, vol. 153, pp. 441 – 446, 2006.

48.L. Kolodziejski, R. Gunshor, S. Datta, W. Becker, A. Nurmikko, ”Wide-gap II-VI superlattices,” IEEE Quantum Electronics, vol. 22, pp. 1666–1676, 1986.

49.J. K. Sheu, J. M. Tsai, S. C. Shei, W. C. Lai, T. C. Wen, C. H. Kou, Y. K. Su, S.J. Chang, G. C. Chi, ”Low-operation voltage of InGaN-GaN light-emitting diodes with Si-doped In0.3Ga0.7N/GaN short-period superlattice tunneling contact layer,” IEEE Electron Device Letters, vol. 22, pp. 460–462, 2001.

50.H. C. Wang, Y. K. Su, “Investigation and fabrication of AlGaInP and InGaN-based lighting emitting diodes,” 2004 .

51.A. Yasan, M. Razeghi, “Very high quality p-type AlGaN/GaN superlattice,” Solid-State Electronics, vol. 47, pp. 303-306, 2003.

52. E. F. Schubert, W. Grieshaberand, I.D. Goepfert, ”Enhancement of deep acceptor activation in semiconductors by superlattice doping,” Appl. Phys. Lett., vol. 69, pp. 3737-3739, 1996.

53.L. Zhou, F. Khan , A.T. Ping, A. Osinski and I. Adesida, ”Characteristics of Ti/Pt/Au ohmic contacts on p-type GaN/AlGaN superlattices.” Appl. Phys. Lett., vol. 15, pp. 145-147, 1985.

54.T. C. Wen, S. J. Chang, Y. K. Su, L. W. Wu, C. H. Kuo, Y. P. Hsu, W. C. Lai, J. K. Sheu , “Improved ESD reliability by using a modulation doped AlGaN/GaN superlattice in nitride-based LED,” Semiconductor Device Research Symposium, vol. 19, pp. 77–78, 2003.

55.J. R. Gong, S. F. Tseng, C. W. Huang, Y. L. Tsai, W. T. Liao, C. L. Wang, B. H. Shi, and T. Y. Lin, ”Effects of Al-containing intermediate Ⅲ-nitride strained multilayers on the threading dislocation density and optical properties of GaN films,” Jan. J. Appl. Phys., vol. 42, pp. 6823-6826, 2003.

56.C.L. Wang, J.R. Gong, M.F. Yeh, B.J. Wu, W.T. Liao, T.Y. Lin, and C.K. Lin, “Improvement in the characteristics of GaN-based light-emitting diodes by inserting AlGaN-GaN short-period superlattices in GaN underlayers,” IEEE Photonics Technology Letters, vol. 18, pp.733-735, 2006.

57.Y. H. Sun, Z. G. Li, Y. H. Cheng, J. Yuan, “Joule heating effect on evaluation of lifetime in electromigration experiment,” Solid-State and Integrated Circuit Technology, vol. 3, pp.211-213, 1998.

58. A. Yasuda, H. Yamaguchi, Y. Tanabe, N. Owada, “Direct measurement of localized joule heating in silicon devices by means of newly developed high resolution IR microscopy,” Reliability Physics Symposium, vol. 15, pp. 191-193, 1991.

59.J. H. Lee, Y. D. Lee, Y. B. Park, S. T. Yang, M. S. Suh, Q. H. Chung, K. Y. Byun, “Joule heating effect on the electromigration lifetimes and failure mechanisms of Sn-3.5Ag solder bump,” Electronic Components and Technology Conference, vol. 22, pp. 55-57, 2007.

60.C. L. Wang, J.R. Gong, M.F. Yeh, B.J. Wu, W.T. Liao, T.Y. Lin and C.K. Lin, “Improvement in the characteristics of GaNbased light-emitting diodes by inserting AlGaN/GaN short-period superlattices in GaN underlayers,” IEEE Photonics Technology Letters, vol. 18, pp. 1497-1499, 2006.

61.X.A. Cao, E.B. Stokes, P.M. Sandivk, S.F. Leboeuf, J. Kretchmer, and D. Walker, “Diffusion and tunneling currents in GaN/InGaN multiple quantum well light-emitting diodes”, IEEE Electron Device Letters, vol. 23, pp. 535-537, 2002.

62.S. H. Chiu, S.W. Liang, Y. C. Chen, Y.C. Liu, K.H. Chen, S.H. Lin, “Joule heating effect under accelerated electromigration in flip-chip solder joints,” Electronic Components and Technology Conference, vol. 10, pp. 443-445, 2006.

63.L. W. Ji, Y. K. Su , S. J. Chang, S. C. Hung, C. S. Chang, L.W. Wu, ”Nitride-based light-emitting diodes with InGaN/GaN SAQD active layers,” Circuits, IEE Devices and Systems, vol. 151, pp. 486–488, 2004.

64.S. J. Chang, Y. K. Su, L. W. Ji, S. J. Chang, L. W. Wu, W. C. Lai, T. H. Fag, K. T. Lam, ”Nitride-based QD LEDs,” Semiconductor Device Research Symposium, vol. 5, pp. 81–82, 2003.
65.J. C. Lin, Y. K. Su, S. J. Chang, W. H. Lan, K. C. Huang, W. R. Chen, Y. C. Cheng, W. J. Lin, ”GaN-based light-emitting diodes prepared on vicinal sapphire substrates,” IET Optoelectronics, vol. 1, pp. 23–26, 2007.

66.P. G. Eliseev, J. Lee, M. Osinski, “InGaN-based quantum-well LEDs: explanation of anomalous electro-optical characteristics,” vol. 1, pp. 147-149, Lasers and Electro-Optics, 2005.

67.N. Stavitski, V. Dal, A. Lauwers, C. Vrancken, A.Y. Kovalgin, R. A. M. Wolters, “Systematic TLM measurements of NiSi and PtSi specific contact resistance to n- and p-type Si in a broad doping range,” IEEE Electron Device Letters, vol. 29, pp. 378–381, 2008.

68.N. Stavitski, V. Dal, R. A. M. Wolters, A.Y. Kovalgin, J. Schmitz, “Specific contact resistance measurements of metal-semiconductor junctions,” Microelectronic Test Structures, vol. 17, pp. 19-21, 2006.

69.L. Zhou, F. Khan, A.T. Ping, A. Osinski and I. Aesida, ”Characteristics of Ti/Pt/Au ohmic contacts on p-type GaN/AlGaN superlattices,” Microelectronics Laboratory, Department of Electrical and Computer Engineering, vol. 13, pp. 141-143, 1999.

70.D. J. Dumin and G. J. Pearson,“ Properties of Gallium Arsenide diodes between 4.2K and 300K,” J. Appl. Phys., vol. 36, pp. 3418-3426, 1965.

71.C. A. Kumar, M. Shatalov, V. Adivarahan, A. Lunev, J. W. Yang, G. Simin, M. A. Khan, R. Gaska, and M. Shur, ”High-quality p–n junctions with quaternary AlInGaN/InGaN quantum wells,” Appl. Phys. Lett., vol. 77, pp. 3800, 2000.

72.M. Rodrigues ,”Extraction of schottky diode parameters from current-voltage data for a chemical-vapor-deposited diamond/silicon structure over a wide temperature range,” J. Appl. Phys., vol. 103, pp. 083708, 2008.

73.C. L. Reynolds, Jr. and A. Patel, “Tunneling entity in different injection regimes of InGaN light emitting diodes,” J. Appl. Phys., vol. 103, pp. 086102, 2008 .

74.V. Butenko, R. Kahatabi, E. Mogilko, R. Strul, V. Sandomirsky, Y. Schlesinger, Z. Dashevsky, V. Kasiyan, and S. Genikhov, “Characterization of high-temperature PbTe p-n junctions prepared by thermal diffusion and by ion implantation,” J. Appl. Phys., vol. 103, pp. 024506, 2008.

75.L. X. Zhao, E. J. Thrush, C. J. Humphreys, and W. A. Phillips, “Degradation of GaN-based quantum well light-emitting diodes,” J. Appl. Phys., vol. 103, pp. 024501, 2008.

76.F. Iucolano, F. Roccaforte, F. Giannazzo, and V. Raineri, “Barrier inhomogeneity and electrical properties of Pt/GaN Schottky contacts,” J. Appl. Phys., vol. 102, pp.113701, 2007.

77.J. Osvald, “Influence of lateral current spreading on the apparent barrier parameters of inhomogeneous Schottky diodes”, J. Appl. Phys., vol. 99, pp. 033708, 2006.

78.J. M. Shah, Y. L. Li, T. Gessmann, and E. F. Schubert, “Experimental analysis and theoretical model for anomalously high ideality factors (n2.0) in AlGaN/GaN p-n junction diodes,” J. Appl. Phys., vol. 94, pp. 2627, 2003.

79.X. A. Cao, P. M. Sandvik, E. B. Stokes, S.F. Leboeuf, J. Kretchmer, and D. Walker, “Diffusion and tunneling currents in GaN/InGaN multiple quantum well light-emitting diodes,” IEEE Electron Device Letters, vol. 23, pp. 2231-2233, 2002.

80.H. C. Wang, Y. K. Su, “Investigation and Fabrication of AlGaInP and InGaN-based light-emitting diodes,” Institute of Microelectronics, National Cheng Kung University, Tainan, Taiwan, 2004.

81.J. C. Tseng and J. G. Hwu, “Effects of electrostatic discharge high-field current impulse on oxide breakdown,” J. Appl. Phys., vol. 101, pp. 014103, 2007.

82.S. C. Shei, J. K. Sheu, C. F. Shen, “Improved reliability and ESD characteristics of flip-chip GaN-based LEDs with internal inverse-parallel protection diodes,” IEEE Electron Device Letters, vol. 28, pp. 346–349, 2007.

83.A. M. Fallah, R. M. Nelson,“ Effect of lead length on the response of ESD protection devices”, IEEE Electromagnetic Compatibility, vol. 2, pp. 998–1003, 1999.

84.J. J. Horng, Y. K. Su, S. J. Chang, W. S. Chen, S. C. Shei, “GaN-based power LEDs with CMOS ESD protection circuits,” IEEE Device and Materials Reliability, vol. 7, pp. 340–346, 2007.

85.Y. K. Su, S. J. Chang, S. C. Wei, S. M. Chen, W. L. Li, “ESD engineering of nitride-based LEDs,” IEEE Device and Materials Reliability, vol. 5, pp. 277–281, 2005.