Trend of Crystallization Technology and Large Scale Research for Fabricating Thin Film Transistors of AMOLED Displays

AMOLED 디스플레이의 박막트랜지스터 제작을 위한 결정화 기술 동향 및 대형화 연구

  • Kim, Kyoung-Bo (Department of Metallurgical and Materials Engineering, Inha Technical College) ;
  • Lee, Jongpil (Department of Electrical and Electronic Engineering, Jungwon University) ;
  • Kim, Moojin (Department of Electrical and Electronic Engineering, Jungwon University) ;
  • Min, Youngsil (Department of Pharmaceutical Science, Jungwon University)
  • 김경보 (인하공업전문대학 금속재료과) ;
  • 이종필 (중원대학교 전기전자공학전공) ;
  • 김무진 (중원대학교 전기전자공학전공) ;
  • 민영실 (중원대학교 제약공학과)
  • Received : 2019.02.28
  • Accepted : 2019.05.20
  • Published : 2019.05.28


This paper discusses recent trends in the fabrication of semiconducting materials among the components of thin film transistors used in AMOLED display. In order to obtain a good semiconductor film, it is necessary to change the amorphous silicon into polycrystalline silicon. There are two ways to use laser and heat. Laser-based methods include sequential lateral solidification (SLS), excimer laser annealing (ELA), and thin-beam directional crystallization (TDX). Solid phase crystallization (SPC), super grain silicon (SGS), metal induced crystallization (MIC) and field aided lateral crystallization (FALC) were crystallized using heat. We will also study research for manufacturing large AMOLED displays.

JKOHBZ_2019_v9n5_117_f0001.png 이미지

Fig. 1. Images of (a) black and white, and (b) color CRT televisions.

JKOHBZ_2019_v9n5_117_f0002.png 이미지

Fig. 3. Structure of AMOLED displays composed of polariser, encap, organic layer, and TFT.

JKOHBZ_2019_v9n5_117_f0003.png 이미지

Fig. 5. Schematic diagrams of (a) amorphous and (b) polycrystalline silicon.

JKOHBZ_2019_v9n5_117_f0004.png 이미지

Fig. 6. Processes’ diagram for fabrication of poly-Si TFTs.

JKOHBZ_2019_v9n5_117_f0005.png 이미지

Fig. 7. Surface images of poly-Si layers after (a) SLS, (b) ELA, and (c) TDX processing.

JKOHBZ_2019_v9n5_117_f0006.png 이미지

Fig. 8. Surface images of poly-Si layers after (a) SPC, (b) MIC, (c) SGS, and (c) FALC processing.

JKOHBZ_2019_v9n5_117_f0007.png 이미지

Fig. 9. A schematic diagram showing scanning system and substrate holder inside the process chamber of nickel-sputtering system. Ions are discharged from the plasma which dislodges particles from the metal sputter target. The particles condense on the surface of the glass. The weight of the deposited nickel atom depend on the scanning speed and scanning time of nickel-target on the cathode.

JKOHBZ_2019_v9n5_117_f0008.png 이미지

Fig. 2. (a) LCD and (b) PDP televisions.

JKOHBZ_2019_v9n5_117_f0009.png 이미지

Fig. 4. (a) Loyol's FlexFai and (b) Samsung's Galaxy Fold.

JKOHBZ_2019_v9n5_117_f0010.png 이미지

Fig. 10. (a) Microscope image of long-lateral grains and (b) Brightness non-uniformity induced by oblique lines on SLS poly-Si AMOLED panel.

JKOHBZ_2019_v9n5_117_f0011.png 이미지

Fig. 11. (a) Full-color 5-inch AMOLED display shows a nonuniformity due to the different performance of TFT in the double scanned region. (b) Full-color 2.8-inch AMOLED display fabricated on the single and double scanned area for the excimer laser energy densities of 230 mJ/cm2 on solid phase crystallized silicon films.

JKOHBZ_2019_v9n5_117_f0012.png 이미지

Fig. 12. (a) Basic concept of the RPL design and diagram of the pixel circuit (2 TFTs + 1 capacitor) connection of a simple one line RPL design. (b) The RPL designed panel (b) shows a uniform green image..


Supported by : National Research Foundation (NRF)


  1. M. Diethelm, L. Penninck, S. Altazin, R. Hiestand, C. Kirsch & B. Ruhstaller. (2018). Quantitative analysis of pixel crosstalk in AMOLED displays. Journal of Information Display, 19(2), 61-69. DOI : 10.1080/15980316.2018.1428232
  2. A. Rjoub, B. Tarawneh & R. Alghsoon. (2019). Active matrix organic light emitting diode displays (AMOLED) new pixel design. Microelectronic Engineering, 212, 42-52. DOI : 10.1016/j.mee.2019.04.001
  3. V. C. Bender, N. D. Barth, F. B. Mendes, R. A. Pinto, J. M. Alonso & T. B. Marchesan. (2018). A Hardware Emulator for OLED Panels Applied to Lighting Systems. IEEE Journal of Emerging and Selected Topics in Power Electronics, 6(3), 1252-1258. DOI : 10.1109/JESTPE.2018.2842157
  4. T. K. Kang, T. C. Liao & Y. Y. Yang. (2012). TSelf-Heating and Kink Effects in SLS Single-Crystal-Like Nanowire Transistors. IEEE Transactions on Electron Devices, 59(10), 2787-2794. DOI : 10.1109/TED.2012.2210045
  5. C. Y. Liao, S. H. Chen, W. H. Huang, C. H. Shen, J. M. Shieh & H. C. Cheng. (2018). High-Performance Recessed-Channel Germanium Thin-Film Transistors via Excimer Laser Crystallization. IEEE Electron Device Letters, 39(3), 367-370. DOI : 10.1109/LED.2018.2791506
  6. M. S. Bowen & D. S. Knowles. (2006). Excimer-Laser-Based, Thin Beam Directional 'Xtallization (TDX) and Thin Beam Based LTPS Technology for Processing Large Area Poly-Silicon. The Review of Laser Engineering, 34(10), 689-692. DOI : 10.2184/lsj.34.689
  7. Y. Kawamura, K. Yamasaki, T. Yamashita, Y. Sugawara & Y. Uraoka. (2010). Crystallization by Green-laser Annealing for Three-dimensional Device Application. Journal of the Korean Physical Society, 56(5), 1456-1460. DOI : 10.3938/jkps.56.1456
  8. H. Jin & M. J. Kim. (2010). Characteristics of Excimer Laser-Annealed Thin-Film Transistors on the Polycrystalline Silicon Morphology Formed in the Single and Double (Overlap) Scanned Area. Japanese Journal of Applied Physics, 49(4R), 041301. DOI : 10.1143/JJAP.49.041301
  9. R. Ishikawa, S. Kato, T. Yamazaki, Y. Kurokawa, S. Miyajima & M. Konagai. (2014). Solid-phase crystallization of amorphous silicon nanowire array and optical properties. Japanese Journal of Applied Physics, 53(2S), 02BE09. DOI : 10.7567/JJAP.53.02BE09
  10. J. H. Choi, D. Y. Kim, S. J. Park, B. K. Choo & J. Jang. (2003). Temperature dependence of the growth of super-grain polycrystalline silicon by metal induced crystallization. Thin Solid Films, 427(1-2), 289-293. DOI : 10.1016/S0040-6090(02)01150-1
  11. R. Chen, W. Zhou, M. Zhang, M. Wong & H. S. Kwok. (2015). High-Performance Polycrystalline Silicon Thin-Film Transistors Based on Metal-Induced Crystallization in an Oxidizing Atmosphere. IEEE Electron Device Letters, 36(5), 460-462. DOI : 10.1109/LED.2015.2409858
  12. D. K. Choi, H. C. Kim & Y. B. Kim. (2005). Mechanism of field-aided lateral crystallization of amorphous silicon. Applied Physics Letters, 87(6), 063108. DOI : 10.1063/1.2009066
  13. G. A. Bhat, H. S. Kwok & M Wong. (2000). Behavior of the drain leakage current in metal-induced laterally crystallized thin film transistors. Solid-State Electronics, 44(7), 1321-1324. DOI : 10.1016/S0038-1101(99)00328-7
  14. G. H. Jin, S. M. Choi, M. J. Kim, S. C. Kim & J. H. Song. (2012). New Pixel Circuit Design Employing an Additional Pixel Line Insertion in AMOLED Displays Composed by Excimer Laser-Crystallized TFTs. Journal of Display Technology, 8(8), 479-482. DOI : 10.1109/JDT.2012.2191533
  15. M. J. Kim, G. H. Jin, K. B. Kim & J. H. Song. (2015). Effects of the single and double (overlap) scanned excimer laser annealing on solid phase crystallized silicon films. Displays, 36, 9-12. DOI : 10.1016/j.displa.2014.11.001
  16. K. Sharma, M. Ponomarev, M. A. Verheijen, O. Kunz, M. C. M. van de Sanden & M. Creatore. (2012). Solid-phase crystallization of ultra high growth rate amorphous silicon films. Journal of Applied Physics, 111, 103510. DOI : 10.1063/1.4717951
  17. J. P. Bermundo, Y. Ishikawa, M. N. Fujii, T. Nonaka, R. Ishihara, H. Ikenoue & Y. Uraoka. (2015). Effect of excimer laser annealing on a-InGaZnO thin-film transistors passivated by solution-processed hybrid passivation layers. Journal of Physics D: Applied Physics, 49(3), 035102. DOI : 10.1088/0022-3727/49/3/035102
  18. K. B. Kim, J. P. Lee, M. J. Kim & Y. S. Min. (2019). Characteristics of Excimer Laser-Annealed Polycrystalline Silicon on Polymer layers. Journal of Convergence for Information Technology, 9(3), 75-81. DOI : 10.22156/CS4SMB.2019.9.3.075
  19. H. K. Kim. (2016). A Study on fusion design development direction of the Flexible display base. Journal of Digital Convergence, 14(1), 399-405. DOI : 10.14400/JDC.2016.14.1.399
  20. K. C. Kim. (2017). Development of Shading Tape for Manufacturing of Touch Panel Display with High Screen-to-Body Ratio. Journal of Convergence for Information, 7(4), 75-81. DOI : 10.22156/CS4SMB.2017.7.4.07