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Optical Materials Express

Optical Materials Express

  • Editor: David Hagan
  • Vol. 4, Iss. 8 — Aug. 1, 2014
  • pp: 1632–1640

Performance enhancement of GaN-based flip-chip ultraviolet light-emitting diodes with a RPD AlN nucleation layer on patterned sapphire substrate

B. C. Lin, C. H. Chiu, C. Y. Lee, H. V. Han, P. M. Tu, T. P. Chen, Z. Y. Li, P. T. Lee, C. C. Lin, G. C. Chi, C. H. Chen, B. Fan, C. Y. Chang, and H. C. Kuo  »View Author Affiliations

Optical Materials Express, Vol. 4, Issue 8, pp. 1632-1640 (2014)

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In this work, flip-chip ultraviolet light-emitting diodes (FCUV-LEDs) on patterned sapphire substrate (PSS) at 375 nm were grown by an atmospheric pressure metal organic chemical vapor deposition (AP-MOCVD). A specialized reactive plasma deposited (RPD) AlN nucleation layer was utilized on the PSS to enhance the quality of the epitaxial layer. By using high-resolution X-ray diffraction, the full-width at half-maximum of the rocking curve shows that the FCUV-LEDs with RPD AlN nucleation layer had better crystalline quality when compared to conventional GaN nucleation samples. From the transmission electron microscopy (TEM) image, it can be observed that the tip and incline portion of the pattern was smooth using the RPD AlN nucleation layer. The threading dislocation densities (TDDs) are reduced from 7 × 107 cm−2 to 2.5 × 107 cm−2 at the interface between the u-GaN layers for conventional and AlN PSS devices, respectively. As a result, a much higher light output power was achieved. The improvement of light output power at an injection current of 20 mA was enhanced by 30%. Further photoluminescence measurement and numerical simulation confirm such increase of output power can be attributed to the improvement of material quality and light extraction.

© 2014 Optical Society of America

OCIS Codes
(230.2090) Optical devices : Electro-optical devices
(230.3670) Optical devices : Light-emitting diodes

ToC Category:

Original Manuscript: April 25, 2014
Revised Manuscript: June 19, 2014
Manuscript Accepted: June 20, 2014
Published: July 17, 2014

B. C. Lin, C. H. Chiu, C. Y. Lee, H. V. Han, P. M. Tu, T. P. Chen, Z. Y. Li, P. T. Lee, C. C. Lin, G. C. Chi, C. H. Chen, B. Fan, C. Y. Chang, and H. C. Kuo, "Performance enhancement of GaN-based flip-chip ultraviolet light-emitting diodes with a RPD AlN nucleation layer on patterned sapphire substrate," Opt. Mater. Express 4, 1632-1640 (2014)

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  1. S. Nakamura, M. Senoh, N. Iwsa, and S.-I. Nagahama, “High-brightness InGaN blue, green and yellow light-emtting diodes with quantum well structures,” Jpn. J. Appl. Phys.34(Part 2, No. 7A), L797–L799 (1995). [CrossRef]
  2. T. Mukai, M. Yamada, and S. Nakamura, “Characteristics of InGaN-based UV/blue/green/amber/red light-emitting diodes,” Jpn. J. Appl. Phys.38(Part 1, No. 7A), 3976–3981 (1999). [CrossRef]
  3. Y. C. Chiu, W. R. Liu, C. K. Chang, C. C. Liao, Y. T. Yeh, S. M. Jang, and T. M. Chen, “Ca2PO4Cl:Eu2+: An intense near-ultraviolet converting blue phosphor for white light-emitting diodes,” J. Mater. Chem.20(9), 1755–1758 (2010). [CrossRef]
  4. P. M. Tu, C. Y. Chang, S. C. Huang, C. H. Chiu, J. R. Chang, W. T. Chang, D. S. Wuu, H. W. Zan, C. C. Lin, H. C. Kuo, and C. P. Hsu, “Investigation of efficiency droop for InGaN-based UV light-emitting diodes with InAlGaN barrier,” Appl. Phys. Lett.98(21), 211107 (2011). [CrossRef]
  5. Y. S. Tang, S. F. Hu, C. C. Lin, N. C. Bagkar, and R. S. Liu, “Thermally stable luminescence of KSrPO4:Eu2+ phosphor for white light UV light-emitting diodes,” Appl. Phys. Lett.90(15), 151108 (2007). [CrossRef]
  6. Y. Narukawa, J. Narita, T. Sakamoto, K. Deguchi, T. Yamada, and T. Mukai, “Ultra-high efficiency white light emitting diodes,” Jpn. J. Appl. Phys.45(41), L1084–L1086 (2006). [CrossRef]
  7. S. Nakamura, M. Senoh, S. Nagahama, N. Iwasa, T. Yamada, T. Matsushita, H. Kiyoku, Y. Sugimoto, T. Kozaki, H. Umemoto, M. Sano, and K. Chocho, “InGaN/GaN/AlGaN-based laser diodes with modulation-doped strained-layer structures grown on an epitaxially laterally overgrown GaN substrate,” Appl. Phys. Lett.72(2), 211–213 (1998). [CrossRef]
  8. S. W. Feng, Y. C. Cheng, Y. Y. Chung, C. C. Yang, Y.-S. Lin, C. Hsu, K.-J. Ma, and J.-I. Chyi, “Impact of localized states on the recombination dynamics in InGaN/GaN quantum well structures,” J. Appl. Phys.92(8), 4441–4448 (2002). [CrossRef]
  9. 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.66(10), 1249–1251 (1995). [CrossRef]
  10. T. Wang, Y. H. Lin, Y. B. Lee, Y. Izumi, J. P. Ao, J. Bai, H. D. Li, and S. Sakai, “Fabrication of high performance of AlGaN/GaN-based UV light-emitting diodes,” J. Cryst. Growth235(1-4), 177–182 (2002). [CrossRef]
  11. D. Kapolnek, S. Keller, R. Vetury, R. D. Underwood, P. Kozodoy, S. P. DenBaars, and U. K. Mishra, “Anisotropic epitaxial lateral growth in GaN selective are epitaxy,” Appl. Phys. Lett.71(9), 1204–1206 (1997). [CrossRef]
  12. T. S. Zheleva, O.-H. Nam, M. D. Bremser, and R. F. Davis, “Dislocation density reduction via lateral epitaxy in selectively grown GaN structures,” Appl. Phys. Lett.71(17), 2472–2474 (1997). [CrossRef]
  13. D. M. Follstaedt, P. P. Provencio, N. A. Missert, C. C. Mitchell, D. D. Koleske, A. A. Allerma, and C. I. H. Ashby, “Minimizing threading dislocations by redirection during cantilever epitaxial growth of GaN,” Appl. Phys. Lett.81(15), 2758–2760 (2002). [CrossRef]
  14. M. H. Lo, P. M. Tu, C. H. Wang, Y. J. Cheng, C. W. Hung, S. C. Hsu, H. C. Kuo, H. W. Zan, S. C. Wang, C. Y. Chang, and C. M. Liu, “Defect selective passivation in GaN epitaxial growth and its application to light emitting diodes,” Appl. Phys. Lett.95(21), 211103 (2009). [CrossRef]
  15. A. Sakai, H. Sunakawa, and A. Usui, “Defect structure in selectively grown GaN films with low threading dislocation density,” Appl. Phys. Lett.71(16), 2259–2261 (1997). [CrossRef]
  16. D. S. Wuu, W. K. Wang, K. S. Wen, S. C. Huang, S. H. Lin, S. Y. Huang, C. F. Lin, and R. H. Horng, “Defect reduction and efficiency improvement of near-ultraviolet emitters via laterally overgrown GaN on a GaN/patterned sapphire template,” Appl. Phys. Lett.89(16), 161105 (2006). [CrossRef]
  17. T. V. Cuong, H. S. Cheong, H. G. Kim, H. Y. Kim, C.-H. Hong, E. K. Suh, H. K. Cho, and B. H. Kong, “Enhanced light output from aligned micropit InGaN-based light emitting diodes using wet-etch sapphire patterning,” Appl. Phys. Lett.90(13), 131107 (2007). [CrossRef]
  18. Y. J. Lee, J. M. Hwang, T. C. Hsu, M. H. Hsieh, M. J. Jou, B. J. Lee, T. C. Lu, H. C. Kuo, and S. C. Wang, “Enhancing the output power of GaN-based LEDs grown on chemical wet etching patterned sapphire substrate,” IEEE Photon. Technol. Lett.18(10), 1152–1154 (2006). [CrossRef]
  19. Z. H. Feng, Y. D. Qi, Z. D. Lu, and K. M. Lau, “GaN-based blue light-emitting diodes grown and fabricated on patterned sapphire substrates by metalorganic vapor-phase epitaxy,” J. Cryst. Growth272(1-4), 327–332 (2004). [CrossRef]
  20. H. C. Lin, H. H. Liu, G. Y. Lee, J. I. Chyi, C. M. Lu, C. W. Chao, T. C. Wang, C. J. Chang, and S. W. S. Chi, “Effects of lens shape on GaN grown on microlens patterned sapphire substrates by metallorganic chemical vapor deposition,” J. Electrochem. Soc.157(3), H304–H307 (2010). [CrossRef]
  21. K. C. Shen, D. S. Wuu, C. C. Shen, S. L. Ou, and R. H. Horng, “Surface modification on wet-etched patterned sapphire substrates using plasma treatments for improved GaN crystal quality and LED performance,” J. Electrochem. Soc.158(10), H988–H993 (2011). [CrossRef]
  22. B. W. Lin, C. Y. Hsieh, B. M. Wang, W. C. Hsu, and Y. S. Wu, “Improved performance of GaN-based LEDs by covering top c-plane of patterned sapphire substrate with oxide layer,” Electrochem. Solid-State Lett.14(8), J48–J50 (2011). [CrossRef]
  23. W. C. Lai, C. H. Yen, Y. Y. Yang, C. K. Wang, and S. J. Chang, “GaN-based ultraviolet light emitting diodes with ex situ sputtered AlN nucleation layer,” J. Display Technol.9(11), 895–899 (2013). [CrossRef]
  24. C. H. Yen, W. C. Lai, Y. Y. Yang, C. K. Wang, T. K. Ko, S. J. Hon, and S. J. Chang, “GaN-based light emitting diode with sputtered AlN nucleation layer,” IEEE Photon. Technol. Lett.24(4), 294–296 (2012). [CrossRef]
  25. H. Heinke, V. Kirchner, S. Einfeldt, and D. Hommel, “X-ray diffraction analysis of the defect structure in epitaxial GaN,” Appl. Phys. Lett.77(14), 2145–2147 (2000). [CrossRef]
  26. B. Heying, X. H. Wu, S. Keller, Y. Li, D. Kapolnek, B. P. Keller, S. P. DenBaar, and J. S. Speck, “Role of threading dislocation structure on the x‐ray diffraction peak widths in epitaxial GaN films,” Appl. Phys. Lett.68(5), 643–646 (1996). [CrossRef]
  27. H. Amano, N. Sawaki, I. Akasaki, and Y. Toyoda, “Metalorganic vapor phase epitaxial growth of a high quality GaN film using an AlN buffer layer,” Appl. Phys. Lett.48(5), 353 (1986). [CrossRef]
  28. S. Watanabe, N. Yamada, M. Nagashima, Y. Ueki, C. Sasaki, Y. Tamada, T. Taguchi, and H. Kudo, “Internal quantum efficiency of highly-efficient InxGa1–xN-based near-ultraviolet light-emitting diodes,” Appl. Phys. Lett.83(24), 4906–4908 (2003). [CrossRef]
  29. Y. J. Lee, C. H. Chiu, C. C. Ke, P. C. Lin, T. C. Lu, H. C. Kuo, and S. C. Wang, “Study of excitation power dependent internal quantum efficiency in InGaN/GaN LEDs grown on patterned sapphire substrate,” IEEE J. Sel. Top. Quantum Electron.15(4), 1137–1143 (2009). [CrossRef]
  30. C.-H. Chiu, C.-C. Lin, D.-M. Deng, D.-W. Lin, J.-C. Li, Z.-Y. Li, G.-W. Shu, T.-C. Lu, J.-L. Shen, H.-C. Kuo, and K.-M. Lau, “Optical and electrical properties of GaN-based light emitting diodes grown on micro and nano-scale patterned Si substrate,” IEEE J. Quantum Electron.47(7), 899–906 (2011). [CrossRef]
  31. M. A. Tsai, P. Yu, C. H. Chiu, H. C. Kuo, T. C. Lu, and S. H. Lin, “Self-assembled two-dimensional surface structures for beam shaping of GaN-based vertical-injection light-emitting diodes,” IEEE Photon. Technol. Lett.22(1), 12–14 (2010). [CrossRef]
  32. Fullwave 6.1, RSoft Design Group Inc., Ossining, NY, 2008.

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