Journal of Materials Science

, Volume 53, Issue 12, pp 8878–8886 | Cite as

Enhanced performance of GaN-based LEDs via electroplating of a patterned copper layer on the backside

  • Wael Z. Tawfik
  • Gil Yong Hyun
  • Seong Jea Lee
  • Sang-Wan Ryu
  • Jun-Seok Ha
  • June Key Lee
Chemical routes to materials


InGaN/GaN multi-quantum well light-emitting diodes (LEDs) are conventionally grown on a sapphire substrate due to a lack of compatible substrates with a high compressive strain. This is a result of the relatively large lattice, and thermal expansion coefficient mismatches between GaN and sapphire. The compressive strain is considered to be a major obstacle to further improve next-generation high-performance GaN-based LEDs. In this paper, we have designed, electroplated, and tested an efficient substrate using a patterned copper (Cu) layer on the backside of sapphire to relax the compressive strain in a GaN epilayer. The patterned Cu layer has a significant function in that it supports the GaN/sapphire LEDs with an external tensile stress. The external tensile stress is capable of compensating for the compressive strain in the GaN/sapphire LEDs by controlling the curvature of the wafer bowing. This patterned Cu layer, when applied to the GaN/sapphire LEDs, suppresses the compressive strain by up to 0.28 GPa. The GaN-based LEDs on this innovative and effective sapphire/Cu substrate offer improved optical and electrical performance.



This study was financially supported by Chonnam National University (Grant Number 2016-2443).

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.


  1. 1.
    Nakamura S, Senoh M, Mukai T (1991) High-power GaN p–n junction blue-light-emitting diodes. Jpn J Appl Phys 2:L1998–L2001CrossRefGoogle Scholar
  2. 2.
    Akasaki I, Amano H (2006) Breakthroughs in improving crystal quality of GaN and invention of the p–n junction bluelight-emitting diode. Jpn J Appl Phys 1:9001–9010CrossRefGoogle Scholar
  3. 3.
    Amano H, Kito M, Hiramatsu K, Akasaki I (1989) P-type conduction in Mg-doped GaN treated with low-energy electron beam irradiation (LEEBI). Jpn J Appl Phys 2:L2112–L2114CrossRefGoogle Scholar
  4. 4.
    Nakamura S, Senoh M, Mukai T (1993) P-GaN/N-InGaN/N-GaN double-heterostructure blue-light-emitting diodes. Jpn J Appl Phys 2:L8–L11CrossRefGoogle Scholar
  5. 5.
    Khan MA, Bhattarai A, Kuznia JN, Olson DT (1993) High electron mobility transistor based on a GaN-AlxGa1−xN heterojunction. Appl Phys Lett 63:1214–1215CrossRefGoogle Scholar
  6. 6.
    Chichibu SF, Uedono A, Onuma T, Haskell BA, Chakraborty A, Koyama T, Fini PT, Keller S, Denbaars SP, Speck JS, Mishra UK, Nakamura S, Yamaguchi S, Kamiyama S, Amano H, Akasaki I, Han J, Sota T (2006) Origin of defect-insensitive emission probability in In-containing (Al, In, Ga)N alloy semiconductors. Nat Mater 5:810–816CrossRefGoogle Scholar
  7. 7.
    Cao XA, Yang Y, Guo H (2008) On the origin of efficiency roll-off in InGaN-based light-emitting diodes. J Appl Phys 104:093108-4Google Scholar
  8. 8.
    Kioupakis E, Yan Q, Van de Walle CG (2012) Interplay of polarization fields and Auger recombination in the efficiency droop of nitride light-emitting diodes. Appl Phys Lett 101:231107-4CrossRefGoogle Scholar
  9. 9.
    Son JH, Lee JL (2010) Strain engineering for the solution of efficiency droop in InGaN/GaN light-emitting diodes. Opt Express 18:5466–5571CrossRefGoogle Scholar
  10. 10.
    Nakamura S, Senoh M, Shin-ichi Nagahama N, Iwasa T, Yamada T, Matsushita H, Kiyoku Y, Sugimoto T, Kozaki H, Umemoto M, Sano K Chocho (1998) InGaN/GaN/AlGaN-based laser diodes grown on GaN substrates with a fundamental transverse mode. Jpn J Appl Phys 37:L1020–L1022CrossRefGoogle Scholar
  11. 11.
    Zhou S, Yuan S, Liu Y, Jay Guo L, Liu S, Ding H (2015) Highly efficient and reliable high power LEDs with patterned sapphire substrate and strip-shaped distributed current blocking layer. Appl Surf Sci 355:1013–1019CrossRefGoogle Scholar
  12. 12.
    Lv J, Zheng Ch, Zhou S, Fang F, Yuan S (2016) Highly efficient and reliable high power InGaN/GaN LEDs with 3D patterned step-like ITO and wavy sidewalls. Phys Status Solidi A 213:1181–1186CrossRefGoogle Scholar
  13. 13.
    Lin Z, Wang H, Wang W, Lin Y, Yang M, Chen S, Li G (2016) Employing low-temperature barriers to achieve strain-relaxed and high-performance GaN-based LEDs. Opt Express 24:11885–11896CrossRefGoogle Scholar
  14. 14.
    Zhang L, Yu J, Hao X, Wu Y, Dai Y, Shao Y, Zhang H, Tian Y (2014) Influence of stress in GaN crystals grown by HVPE on MOCVD-GaN/6H-SiC substrate. Sci Rep 4:4179–4184CrossRefGoogle Scholar
  15. 15.
    Gardner NF, Kim JC, Wierer JJ, Shen YC, Krames MR (2005) Polarization anisotropy in the electroluminescence of m-plane InGaN–GaN multiple-quantum-well light-emitting diodes. Appl Phys Lett 86:111101–111103CrossRefGoogle Scholar
  16. 16.
    Tawfik WZ, Hyun GY, Ryu S-W, Ha JS, Lee JK (2016) Piezoelectric field in highly stressed GaN-based LED on Si (1 1 1) substrate. Opt Mater 55:17–21CrossRefGoogle Scholar
  17. 17.
    Wang W, Yan T, Yang W, Zhu Y, Wang H, Li G, Ye N (2016) Epitaxial growth of GaN films on lattice-matched ScAlMgO4 substrates. CrystEngComm 18:4688–4694CrossRefGoogle Scholar
  18. 18.
    He G, Chichibu SF, Chikyow T (2011) Microstructure and interface control of GaN/MgAl2O4 grown by metalorganic chemical vapor deposition: substrate-orientation dependence. J Appl Phys 110:023504–023508CrossRefGoogle Scholar
  19. 19.
    Yang W, Wang W, Liu Z, Lin Y, Zhou S, Qian H, Li G (2015) Epitaxial growth and its mechanism of GaN films on nitrided LiGaO2(001) substrates by pulsed laser deposition. CrystEngComm 17:1073–1079CrossRefGoogle Scholar
  20. 20.
    Haskell BA, Chakraborty A, Wu F, Sasano H, Fini PT, Denbaas SP, Speck JS, Nakamura S (2005) Microstructure and enhanced morphology of planar nonpolar m-plane GaN grown by hydride vapor phase epitaxy. J Electron Mater 34:357–360CrossRefGoogle Scholar
  21. 21.
    Sakowska H, Swirkowicz M, Mazur K, Lukasiewicz T, Witek A (2001) Growth and characterization of (La, Sr)(Al, Ta)O3 single crystals: a promising substrate for GaN epitaxial growth. Cryst Res Technol 36:851–858CrossRefGoogle Scholar
  22. 22.
    Li G, Wang W, Yang W, Lin Y, Wang H, Lin Z, Zhou S (2016) GaN-based light-emitting diodes on various substrates: a critical review. Rep Prog Phys 79:056501–056549CrossRefGoogle Scholar
  23. 23.
    Li G, Wang W, Yang W, Wang H (2015) Epitaxial growth of group III-nitride films by pulsed laser deposition and their use in the development of LED devices. Surf Sci Rep 70:380–423CrossRefGoogle Scholar
  24. 24.
    Li G, Shih S-J, Li F (2010) Growth and electron microscopy study of GaN/MgAl2O4 heterostructures. Phys Status Solidi A 207:1302–1304CrossRefGoogle Scholar
  25. 25.
    Jung BO, Bae S-Y, Kato Y, Imura M, Lee D-S, Honda Y, Amano H (2014) Morphology development of GaN nanowires using a pulsed-mode MOCVD growth technique. CrystEngComm 16:2273–2282CrossRefGoogle Scholar
  26. 26.
    Kuzmik J, Bychikhin S, Pogany D, Pichonat E, Lancry O, Gaquière C, Tsiakatouras G, Deligeorgis G, Georgakilas A (2011) Thermal characterization of MBE-grown GaN/AlGaN/GaN device on single crystalline diamond. J Appl Phys 109:086106-3CrossRefGoogle Scholar
  27. 27.
    Tawfik WZ, Song J, Lee JJ, Ha JS, Ryu S-W, Choi HS, Ryu B, Lee JK (2013) Effect of external tensile stress on blue InGaN/GaN multi-quantum-well light-emitting diodes. Appl Surf Sci 283:727–731CrossRefGoogle Scholar
  28. 28.
    Tawfik WZ, Bae S-J, Yang SB, Jeong T, Lee JK (2013) Stress engineering by controlling sapphire substrate thickness in 520 nm GaN-based light-emitting diodes. Appl Phys Express 6:122103–122104CrossRefGoogle Scholar
  29. 29.
    Ryu B, Tawfik WZ, Bae S-J, Ha JS, Ryu S-W, Choi HS, Lee JK (2013) Uni-axial external stress effect on green InGaN/GaN multi-quantum-well light-emitting diodes. J Phys D Appl Phys 46:435103–435106CrossRefGoogle Scholar
  30. 30.
    Tawfik WZ, Bae S-J, Ryu S-W, Jeong T, Lee JK (2014) Effect of residual compressive stress on near-ultraviolet InGaN/GaN multi-quantum well light-emitting diodes. Opt Mater 38:131–136CrossRefGoogle Scholar
  31. 31.
    Tawfik WZ, Hyeon GY, Lee JK (2014) Stress-induced piezoelectric field in GaN-based 450-nm light-emitting diodes. J Appl Phys 116:164503–164506CrossRefGoogle Scholar
  32. 32.
    Tawfik WZ, Ryu H-Y, Lee JK (2014) Electroreflectance spectroscopy of compressively strained InGaN/GaN multi-quantum well structures. Curr Appl Phys 14:1504–1508CrossRefGoogle Scholar
  33. 33.
    Tawfik WZ, Bea S-J, Yang SB, Ryu S-W, Lee JK (2015) Effect of sapphire substrate thickness on the characteristics of 450 nm InGaN/GaN multi-quantum well light-emitting diodes. J Nanosci Nanotechnol 15:5140–5143CrossRefGoogle Scholar
  34. 34.
    Ryou J-H, Lee W, Limb J, Yoo D, Liu JP, Dupuis RD, Wu ZH, Fischer AM, Ponce FA (2008) Control of quantum-confined Stark effect in InGaN/GaNInGaN/GaN multiple quantum well active region by pp-type layer for III-nitride-based visible light emitting diodes. Appl Phys Lett 92:101113-3CrossRefGoogle Scholar
  35. 35.
    Kim S, Jang J-H, Lee J-S, Duquette DJ (2007) Stress behavior of electrodeposited copper films as mechanical supporters for light emitting diodes. Electrochim Acta 52:5258–5265CrossRefGoogle Scholar
  36. 36.
    Zhang L, Li X, Shao Y, Yu J, Wu Y, Hao X, Yin Z, Dai Y, Tian Y, Huo Q, Shen Y, Hua Z, Zhang B (2015) Improving the quality of GaN crystals by using graphene or hexagonal boron nitride nanosheets substrate. ACS Appl Mater Interfaces 7:4504–4510CrossRefGoogle Scholar
  37. 37.
    Mun D-H, Bae H, Bae S, Lee H, Ha J-S, Lee S (2014) Stress relaxation of GaN microstructures on a graphene-buffered Al2O3 substrate. Phys Status Solidi RRL 8:341–344CrossRefGoogle Scholar
  38. 38.
    Park AH, Seo TH, Chandramohan S, Lee GH, Min KH, Lee S, Kim MJ, Hwang YG, Suh E-K (2015) Efficient stress-relaxation in InGaN/GaN light-emitting diodes using carbon nanotubes. Nanoscale 7:15099–15105CrossRefGoogle Scholar
  39. 39.
    Cammarata RC, Trimble TM, Srolovitz DJ (2000) Surface stress model for intrinsic stresses in thin films. J Mater Res 15:2468–2474CrossRefGoogle Scholar
  40. 40.
    Zhou S, Liu X, Gao Y, Liu Y, Liu M, Liu Z, Gui Ch, Liu S (2017) Numerical and experimental investigation of GaN-based flip-chip light-emitting diodes with highly reflective Ag/TiW and ITO/DBR Ohmic contacts. Opt Express 25:26615–26627CrossRefGoogle Scholar
  41. 41.
    Lin DW, Lin CC, Chiu CH, Lee CY, Yang YY, Li ZY, Lai WC, Lu TC, Kuo HC, Wang SC (2011) GaN-based LEDs grown on HVPE growth high crystalline quality thick GaN template. J Electrochem Soc 158:H1103–H1106CrossRefGoogle Scholar
  42. 42.
    Han N, Park YJ, Han M, Ryu BD, Ko KB, Chandramohan S, Choi C-J, Cuong TV, Hong C-H (2014) Threading dislocation reduction in epitaxial GaN using V-groove patterned sapphire substrate with embedded silica nanospheres. Mater Lett 123:97–100CrossRefGoogle Scholar

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Authors and Affiliations

  1. 1.Department of Physics, Faculty of ScienceBeni-Suef UniversityBeni-SuefEgypt
  2. 2.Department of Materials Science and EngineeringChonnam National UniversityGwangjuRepublic of Korea
  3. 3.Optoelectronics Convergence Research CenterChonnam National UniversityGwangjuRepublic of Korea

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