J. Semicond. > 2013, Volume 34 > Issue 11 > 114006
|

SEMICONDUCTOR DEVICES

Light-extraction enhancement of freestanding GaN-based flip-chip light-emitting diodes using two-step roughening methods

Tielei An1, , Bo Sun1, Tongbo Wei1, Lixia Zhao1, Ruifei Duan1, Yuanxun Liao2, Jinmin Li1 and Futing Yi2

+ Author Affiliations

 Corresponding author: An Tielei, Email:tielei@semi.ac.cn

DOI: 10.1088/1674-4926/34/11/114006

PDF

Abstract: The light extraction enhancement of freestanding GaN-based flip-chip light-emitting diodes (FS-FCLEDs) using two-step roughening methods is investigated. The output power of LEDs fabricated by using one-step and two-step roughening methods are compared. The results indicate that two-step roughening methods show more potential for light extraction. Compared with flat FS-FCLEDs, the output power of FS-FCLEDs with a nanotextured hemisphere surface shows an enhancement of 90.7%.

Key words: freestanding GaN, flip chip, LED, CsCl, wet etching, light extraction



[1]
Kim K K, Lee S, Kim H, et al. Enhanced light extraction ef-ciency of GaN-based light-emitting diodes with ZnO nanorod arrays grown using aqueous solution. Appl Phys Lett, 2009, 94:071118 doi: 10.1063/1.3077606
[2]
Wierer J J, David A, Megens M M. Ⅲ-nitride photonic-crystal light-emitting diodes with high extraction ef-ciency. Nature Photonics, 2009, 3:163 doi: 10.1038/nphoton.2009.21
[3]
Fu X X, Zhang B, Kang X N, et al. GaN-based light-emitting diodes with photonic crystals structures fabricated by porous anodic alumina template. Opt Express, 2011, 19(S5):A1104 doi: 10.1364/OE.19.0A1104
[4]
Wei T, Wu K, Lan D. Selectively grown photonic crystal structures for high efficiency InGaN emitting diodes using nanospherical-lens lithography. Appl Phys Lett, 2012, 101:211111 doi: 10.1063/1.4767334
[5]
Kim J K, Noemaun A N, Mont F W, et al. Elimination of total internal reflection in GaInN light-emitting diodes by graded-refractive-index micropillars. Appl Phys Lett, 2008, 93:221111 doi: 10.1063/1.3041644
[6]
Li X H, Song R, Ee Y K, et al. Light Extraction efficiency and radiation patterns of Ⅲ-nitride light-emitting diodes with colloidal microlens arrays with various aspect ratios. IEEE Photonics Journal, 2011, 3(3):489 doi: 10.1109/JPHOT.2011.2150745
[7]
Wei T B, Wu K, Chen Y, et al. Improving light output of vertical-stand-type InGaN light-emitting diodes grown on a free-standing GaN substrate with self-assembled conical arrays. IEEE Electron Device Lett, 2012, 33(6):857 doi: 10.1109/LED.2012.2192092
[8]
Fujii T, Gao Y, Sharma R, et al. Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening. Appl Phys Lett, 2004, 84(6):85
[9]
Tamboli A C, Schmidt M C, Rajan S, et al. Smooth top-down photoelectrochemical etching of M-plane GaN. J Electrochem Soc, 2009, 156(1):H47 doi: 10.1149/1.3005978
[10]
Jung Y, Baik K H, Ren F, et al. Effects of photoelectrochemical etching of N-polar and Ga-polar gallium nitride on sapphire substrates. J Electrochem Soc, 2010, 157(6):H676 doi: 10.1149/1.3384713
[11]
Qi S L, Chen Z Z, Fang H, et al. Study on the formation of dodecagonal pyramid on nitrogen polar GaN surface etched by hot H3PO4. Appl Phys Lett, 2009, 95(7):071114 doi: 10.1063/1.3211970
[12]
Fu Y K, Chen B C, Fang Y H, et al. Study of InGaN-based light-emitting diodes on a roughened backside GaN substrate by a chemical wet-etching process. IEEE Photon Technol Lett, 2011, 23(19):1373 doi: 10.1109/LPT.2011.2161276
[13]
Lee W C, Wang S J, Uang K M, et al. Enhanced light output of GaN-based vertical light-emitting diodes with superimposed circular protrusions and hexagonal cones. Electrochem Solid State, 2011, 14(2):H53 doi: 10.1149/1.3514094
[14]
Kim H, Choi K K, Kim K K, et al. Light-extraction enhancement of vertical-injection GaN-based light-emitting diodes fabricated with highly integrated surface textures. Opt Lett, 2008, 33(11):1273 doi: 10.1364/OL.33.001273
[15]
Horng R H, Hu H L, Chu M T, et al. Performance of flip-chip thin-film GaN light-emitting diodes with and without patterned sapphires. IEEE Photonics Technol Lett, 2010, 22(8):550 doi: 10.1109/LPT.2010.2042590
[16]
Sun Y, Yu T, Chen Z, et al. Properties of GaN-based light-emitting diode thin film chips fabricated by laser lift-off and transferred to Cu. Semicond Sci Technol, 2008, 23(12):125022 doi: 10.1088/0268-1242/23/12/125022
[17]
Shchekin O B, Epler J E, Trottier T A, et al. High performance thin-film flip-chip InGaN-GaN light-emitting diodes. Appl Phys Lett, 2006, 89(7):071109 doi: 10.1063/1.2337007
[18]
Fang Y H, Xuan R, Chao C L. Improvement of the droop efficiency in InGaN-based light-emitting diodes by growing on GaN substrate. Phys Status Solidi C, 2012, 9(3/4):786
[19]
Chao C L, Xuan R, Yen H H, et al. Reduction of ef-ciency droop in InGaN light-emitting diode grown on self-separated freestanding GaN Substrates. IEEE Photon Technol Lett, 2011, 23(12):798 doi: 10.1109/LPT.2011.2134081
[20]
Brinkley S E, Keraly C L, Sonoda J, et al. Chip shaping for light extraction enhancement of bulk C-plane light-emitting diodes. Appl Phys Express, 2012, 5(3):032104 doi: 10.1143/APEX.5.032104
[21]
Fu Y K, Lu Y H, Xuan R, et al. Optical simulation and fabrication of near-ultraviolet LEDs on a roughened backside GaN substrate. IEEE Photon Technol Lett, 2012, 24(6):488 doi: 10.1109/LPT.2011.2182606
[22]
Liao Y X, Yi F T. Nanopillars by cesium chloride self-assembly and dry etching. Nanotechnology, 2010, 21(46):465302 doi: 10.1088/0957-4484/21/46/465302
[23]
Sun B, Zhao L, Wei T, et al. Light extraction enhancement of bulk GaN light-emitting diode with hemisphere-cones-hybrid surface. Opt Express, 2012, 20(17):18537 doi: 10.1364/OE.20.018537
Fig. 1.  The schematic layer structure of FCLEDs fabricated on freestanding GaN substrates. (a) FS-FCLED-A: without surface roughening. (b) FS-FCLED-B: with surface roughening by KOH solution. (c) FS-FCLED-C1: with surface roughening using CsCl nano-islands as etching mask. (d) FS-FCLED-C: with integrated surface roughening

DownLoad: Full-Size Img PowerPoint
Fig. 2.  45$^\circ$ tilt SEM images of the top surface of N-face freestanding GaN: (a) hemispheres using CsCl nano-islands as etching mask, next further roughening with KOH solution for (b) 180 s, (c) 300 s, (d) 600 s, (e) 900 s; and only roughening with KOH solution for (f) 300s. The inset shows the magnified view of the top surface of bulk GaN

DownLoad: Full-Size Img PowerPoint
Fig. 3.  Light output power of the nanotextured FS-FCLED B as a function of chemical etching times

DownLoad: Full-Size Img PowerPoint
Fig. 4.  The comparison of L-I (light output power-current) characteristics of FS-FCLED-A, B, C

DownLoad: Full-Size Img PowerPoint
Fig. 5.  The electronic field distribution around the nanotextured surface and the optical microscopic images at injection current 10 mA for FS-FCLED A, B, C, respectively

DownLoad: Full-Size Img PowerPoint
[1]
Kim K K, Lee S, Kim H, et al. Enhanced light extraction ef-ciency of GaN-based light-emitting diodes with ZnO nanorod arrays grown using aqueous solution. Appl Phys Lett, 2009, 94:071118 doi: 10.1063/1.3077606
[2]
Wierer J J, David A, Megens M M. Ⅲ-nitride photonic-crystal light-emitting diodes with high extraction ef-ciency. Nature Photonics, 2009, 3:163 doi: 10.1038/nphoton.2009.21
[3]
Fu X X, Zhang B, Kang X N, et al. GaN-based light-emitting diodes with photonic crystals structures fabricated by porous anodic alumina template. Opt Express, 2011, 19(S5):A1104 doi: 10.1364/OE.19.0A1104
[4]
Wei T, Wu K, Lan D. Selectively grown photonic crystal structures for high efficiency InGaN emitting diodes using nanospherical-lens lithography. Appl Phys Lett, 2012, 101:211111 doi: 10.1063/1.4767334
[5]
Kim J K, Noemaun A N, Mont F W, et al. Elimination of total internal reflection in GaInN light-emitting diodes by graded-refractive-index micropillars. Appl Phys Lett, 2008, 93:221111 doi: 10.1063/1.3041644
[6]
Li X H, Song R, Ee Y K, et al. Light Extraction efficiency and radiation patterns of Ⅲ-nitride light-emitting diodes with colloidal microlens arrays with various aspect ratios. IEEE Photonics Journal, 2011, 3(3):489 doi: 10.1109/JPHOT.2011.2150745
[7]
Wei T B, Wu K, Chen Y, et al. Improving light output of vertical-stand-type InGaN light-emitting diodes grown on a free-standing GaN substrate with self-assembled conical arrays. IEEE Electron Device Lett, 2012, 33(6):857 doi: 10.1109/LED.2012.2192092
[8]
Fujii T, Gao Y, Sharma R, et al. Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening. Appl Phys Lett, 2004, 84(6):85
[9]
Tamboli A C, Schmidt M C, Rajan S, et al. Smooth top-down photoelectrochemical etching of M-plane GaN. J Electrochem Soc, 2009, 156(1):H47 doi: 10.1149/1.3005978
[10]
Jung Y, Baik K H, Ren F, et al. Effects of photoelectrochemical etching of N-polar and Ga-polar gallium nitride on sapphire substrates. J Electrochem Soc, 2010, 157(6):H676 doi: 10.1149/1.3384713
[11]
Qi S L, Chen Z Z, Fang H, et al. Study on the formation of dodecagonal pyramid on nitrogen polar GaN surface etched by hot H3PO4. Appl Phys Lett, 2009, 95(7):071114 doi: 10.1063/1.3211970
[12]
Fu Y K, Chen B C, Fang Y H, et al. Study of InGaN-based light-emitting diodes on a roughened backside GaN substrate by a chemical wet-etching process. IEEE Photon Technol Lett, 2011, 23(19):1373 doi: 10.1109/LPT.2011.2161276
[13]
Lee W C, Wang S J, Uang K M, et al. Enhanced light output of GaN-based vertical light-emitting diodes with superimposed circular protrusions and hexagonal cones. Electrochem Solid State, 2011, 14(2):H53 doi: 10.1149/1.3514094
[14]
Kim H, Choi K K, Kim K K, et al. Light-extraction enhancement of vertical-injection GaN-based light-emitting diodes fabricated with highly integrated surface textures. Opt Lett, 2008, 33(11):1273 doi: 10.1364/OL.33.001273
[15]
Horng R H, Hu H L, Chu M T, et al. Performance of flip-chip thin-film GaN light-emitting diodes with and without patterned sapphires. IEEE Photonics Technol Lett, 2010, 22(8):550 doi: 10.1109/LPT.2010.2042590
[16]
Sun Y, Yu T, Chen Z, et al. Properties of GaN-based light-emitting diode thin film chips fabricated by laser lift-off and transferred to Cu. Semicond Sci Technol, 2008, 23(12):125022 doi: 10.1088/0268-1242/23/12/125022
[17]
Shchekin O B, Epler J E, Trottier T A, et al. High performance thin-film flip-chip InGaN-GaN light-emitting diodes. Appl Phys Lett, 2006, 89(7):071109 doi: 10.1063/1.2337007
[18]
Fang Y H, Xuan R, Chao C L. Improvement of the droop efficiency in InGaN-based light-emitting diodes by growing on GaN substrate. Phys Status Solidi C, 2012, 9(3/4):786
[19]
Chao C L, Xuan R, Yen H H, et al. Reduction of ef-ciency droop in InGaN light-emitting diode grown on self-separated freestanding GaN Substrates. IEEE Photon Technol Lett, 2011, 23(12):798 doi: 10.1109/LPT.2011.2134081
[20]
Brinkley S E, Keraly C L, Sonoda J, et al. Chip shaping for light extraction enhancement of bulk C-plane light-emitting diodes. Appl Phys Express, 2012, 5(3):032104 doi: 10.1143/APEX.5.032104
[21]
Fu Y K, Lu Y H, Xuan R, et al. Optical simulation and fabrication of near-ultraviolet LEDs on a roughened backside GaN substrate. IEEE Photon Technol Lett, 2012, 24(6):488 doi: 10.1109/LPT.2011.2182606
[22]
Liao Y X, Yi F T. Nanopillars by cesium chloride self-assembly and dry etching. Nanotechnology, 2010, 21(46):465302 doi: 10.1088/0957-4484/21/46/465302
[23]
Sun B, Zhao L, Wei T, et al. Light extraction enhancement of bulk GaN light-emitting diode with hemisphere-cones-hybrid surface. Opt Express, 2012, 20(17):18537 doi: 10.1364/OE.20.018537

    • Search

    Advanced Search >>

    GET CITATION

    shu

    Export: BibTex EndNote

    Article Metrics

    Article views: 2381 Times PDF downloads: 23 Times Cited by: 0 Times

    History

    Received: 16 April 2013 Revised: 17 May 2013 Online: Published: 01 November 2013

    Catalog

      Email This Article

      User name:
      Email:*请输入正确邮箱
      Code:*验证码错误
      Send
      Article Navigation >  Journal of Semiconductors  > 2013  >  34(11): 114006
      Tielei An, Bo Sun, Tongbo Wei, Lixia Zhao, Ruifei Duan, Yuanxun Liao, Jinmin Li, Futing Yi. Light-extraction enhancement of freestanding GaN-based flip-chip light-emitting diodes using two-step roughening methods[J]. Journal of Semiconductors, 2013, 34(11): 114006. doi: 10.1088/1674-4926/34/11/114006 ****T L An, B Sun, T B Wei, L X Zhao, R F Duan, Y X Liao, J M Li, F T Yi. Light-extraction enhancement of freestanding GaN-based flip-chip light-emitting diodes using two-step roughening methods[J]. J. Semicond., 2013, 34(11): 114006. doi: 10.1088/1674-4926/34/11/114006.
      Citation:
      Tielei An, Bo Sun, Tongbo Wei, Lixia Zhao, Ruifei Duan, Yuanxun Liao, Jinmin Li, Futing Yi. Light-extraction enhancement of freestanding GaN-based flip-chip light-emitting diodes using two-step roughening methods[J]. Journal of Semiconductors, 2013, 34(11): 114006. doi: 10.1088/1674-4926/34/11/114006 ****
      T L An, B Sun, T B Wei, L X Zhao, R F Duan, Y X Liao, J M Li, F T Yi. Light-extraction enhancement of freestanding GaN-based flip-chip light-emitting diodes using two-step roughening methods[J]. J. Semicond., 2013, 34(11): 114006. doi: 10.1088/1674-4926/34/11/114006.
      shu

      Light-extraction enhancement of freestanding GaN-based flip-chip light-emitting diodes using two-step roughening methods

      DOI: 10.1088/1674-4926/34/11/114006
      • 1.

        Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China

      • 2.

        Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China

      Funds:

      the National Natural Science Foundation of China 61274008

      the National High Technology Program of China 2011AA03A103

      the National Basic Research Program of China 2011CB301902

      the National Natural Science Foundation of China 61274040

      Project supported by the National Natural Science Foundation of China (Nos. 61274040, 61274008), the National Basic Research Program of China (No. 2011CB301902), and the National High Technology Program of China (No. 2011AA03A103)

      More Information
      • Corresponding author: An Tielei, Email:tielei@semi.ac.cn
      • Received Date: 2013-04-16
      • Revised Date: 2013-05-17
      • Published Date: 2013-11-01

      Catalog

        Journal of Semiconductors © 2017 All Rights Reserved   京ICP备05085259号-2

        /

        DownLoad:  Full-Size Img  PowerPoint
        Return
        Return