Journal of Convergence for Information Technology (융합정보논문지)

Convergence Society for SMB (중소기업융합학회)
권호 표지
DOI QR코드

DOI QR Code

Characteristics of Excimer Laser-Annealed Polycrystalline Silicon on Polymer layers

폴리머 위에 엑시머 레이저 방법으로 결정화된 다결정 실리콘의 특성

  • 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 : 2019.02.06
  • Accepted : 2019.03.20
  • Published : 2019.03.28
Download PDF
⟨ Previous Next ⟩

Abstract

In this work, we investigated a low temperature polycrystalline silicon (LTPS) thin film transistors fabrication process on polymer layers. Dehydrogenation and activation processes were performed by a furnace annealing at a temperature of $430^{\circ}C$ for 2 hr. The crystallization of amorphous silicon films was formed by excimer laser annealing (ELA) method. The p-type device performance, fabricated by polycrystalline silicon (poly-Si) films, shows a very good performance with field effect mobility of $77cm^2/V{\cdot}s$ and on/off ratio current ratio > $10^7$. We believe that the poly-Si formed by a LTPS process may be well suited for fabrication of poly-Si TFTs for bendable panel displays such as AMOLED that require circuit integration.

본 논문은 유기물로 이루어진 폴리머 기판상에 저온 다결정 실리콘 박막트랜지스터 제조방법에 대해 연구하였다. 먼저, 폴리머 기판에 화학증착방식으로 비결정 실리콘 박막을 증착하였고, 열처리 장치인 퍼니스로 탈수소 및 활성화 공정을 430도에서 2시간동안 진행하였다. 이후 엑시머 레이저를 이용하여 결정화를 진행하여 다결정 실리콘 반도체 막을 제조하였다. 이 박막은 박막트랜지스터 제작을 위한 활성층으로 사용하였다. 제작된 p형 박막트랜지스터는 이동도 $77cm^2/V{\cdot}s$, on/off 전류비는 $10^7$이상의 동작특성을 보였고, 이는 결정화된 박막내부에 결함 농도가 낮음을 의미한다. 이 결과로 유기물 기판상에 엑시머 레이저로 형성된 다결정 실리콘으로 제작된 전자소자는 플렉서블 AMOLED 디스플레이 회로 형성에 최적의 기술임을 알 수 있다.

Keywords

JKOHBZ_2019_v9n3_75_f0001.png 이미지

Fig. 1. Photographs showing (a) Samsung Galaxy S6 Edge, (b) Samsung Gear S2 Classic, and (c) Samsung Galaxy Tab S 8.4-inch.

JKOHBZ_2019_v9n3_75_f0002.png 이미지

Fig. 2. Flexible AMOLED panels of (a) LG display and (b)Samsung display.

JKOHBZ_2019_v9n3_75_f0003.png 이미지

Fig. 3. Images of (a) Spin coater (Rotation speed: 0~8000 rpm, Hold time: 1~999 sec, Sample size: up to 4 inch) and (b) Furnace (Temperature: up to 1000 oC, Atmosphere: N2, Ar, Air) equipments.

JKOHBZ_2019_v9n3_75_f0004.png 이미지

Fig. 5. Images of (a) PECVD (RF frequency: 13.56 MHz, Process temperature: 100~400 oC) and (b) ELA (Wavelength: 308 nm, Frequency: up to 300 Hz) equipments.

JKOHBZ_2019_v9n3_75_f0005.png 이미지

Fig. 6. Images of (a) 50-nm amorphous silicon and (b)50-nm polycrystalline silicon film crystallized by XeCl laser processing.

JKOHBZ_2019_v9n3_75_f0006.png 이미지

Fig. 8. Images of (a) Sputter (RF frequency: 13.56 MHz, Temperature: up to 150 oC) and (b) Ion shower (Acceleration voltage: 1 kV~15 kV, phosphorous (P) or boron (B) doping) equipments.

JKOHBZ_2019_v9n3_75_f0007.png 이미지

Fig. 9. Structure of a p-type TFT device.

JKOHBZ_2019_v9n3_75_f0008.png 이미지

Fig. 10. Temperature evolution after 10 seconds of laser pulse-on process: temperature gradient of the a-Si/multilayer film/polymer layer.

JKOHBZ_2019_v9n3_75_f0009.png 이미지

Fig. 11. Pixel circuit design. The green arrow indicates the direction of the current flowing in the OLED by the driving thin film transistor.

JKOHBZ_2019_v9n3_75_f0010.png 이미지

Fig. 13. Transfer curve of (a) before and (b) after delamination for p-type TFTs.

JKOHBZ_2019_v9n3_75_f0011.png 이미지

Fig. 12. Image of probe station (Voltage: -200V~200V, Current level: < 1012 A) equipment.

JKOHBZ_2019_v9n3_75_f0012.png 이미지

Fig. 4. (a) Polymer solution (Fully imidized and excellently chemical resistance, Viscosity: 60∼80 Pa) and (b) Polymer film (Thickness: 15 μm, color: yellowish) coated on glass substrate.

JKOHBZ_2019_v9n3_75_f0013.png 이미지

Fig. 7. (a) SEM plane-view image and (b) AFM surface topography for poly-Si films in the laser irradiation area.

Table 1. Measured device parameters of the p-type TFTs for W/L = 7/7 μm. Values averaged over nine TFTs.

JKOHBZ_2019_v9n3_75_t0001.png 이미지

References

  1. G. H. Jin, J. H. Cho, W. P. Lee, Y. G. Mo, H. D. Kim, S. S. Kim, M. J. Kim & J. H. Song (2011). Simple Fabrication of a Three-Dimensional CMOS Inverter Using p-Type Poly-Si and n-Type Amorphous Ga-In-Zn-O Thin-Film Transistors. IEEE Electron Device Letters, 32(9), 1236-1238. DOI : 10.1109/LED.2011.2161258
  2. M. J. Kim, G. H. Jin, H. K. Min, H. K. Chung, S. S. Kim & J. H. Song. (2010). Effects of Excimer Laser Annealing Process on the Ni-Sputtered Amorphous Silicon Film. Electrochemical and Solid-State Letters, 13(10), H346-H349. DOI : 10.1149/1.3467972
  3. M. J. Kim, K. B. Kim, K. Y. Lee, C. H. Yu, H. D. Kim & H. K. Chung. (2008). Effects of high pressure annealing on the characteristics of solid phase crystallization poly-Si thin-film transistors. Journal of Applied Physics, 103(4), 044508. DOI : 10.1063/1.2885345
  4. M. J. Kim & G. H. Jin. (2009). ITO/AlNdN/Al contact process for active matrix OLED displays. Electronics Letters, 45(8), 421-423. DOI : 10.1049/el.2009.0037
  5. K. Takeuchi, M. Fujino, Y. Matsumoto & T. Suga (2018). Room temperature bonding and debonding of polyimide film and glass substrate based on surface activate bonding method. Japanese Journal of Applied Physics, 57(2S1), 02BB05. DOI : 10.7567/JJAP.57.02BB05
  6. X. Gao, L. Lin, Y. Liu & X. Huang. (2015). LTPS TFT Process on Polyimide Substrate for Flexible AMOLED. Journal of Display Technology, 11(8), 666-669. DOI : 10.1109/JDT.2015.2419656
  7. 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
  8. 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.2017.7.4.075
  9. A. Pecora, L. Maiolo, M. Cuscuna, D. Simeone, A. Minotti, L. Mariucci & G. Fortunato. (2008). Low-temperature polysilicon thin film transistors on polyimide substrates for electronics on plastic. Solid-State Electronics, 52(3), 348-352. DOI : 10.1016/j.sse.2007.10.041
  10. R. Delmdahl, R. Patzel & J. Brune. (2013). Large-area laser-lift-off processing in microelectronics. Physics Procedia, 41, 241-248. DOI : 10.1016/j.phpro.2013.03.075
  11. 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
  12. M. J. Kim, G. H. Jin, K. B. Kim & J. H. Song. (2014). Characteristics of polycrystalline Si TFTs fabricated on glass substrates by excimer laser annealing with nickel-sputtered amorphous Si films. Displays, 35, 1-5. DOI : 10.1016/j.displa.2013.10.002
  13. K. B. Kim, G. H. Jin, M. J. Kim, S. C. Kim & C. W. Jeon. (2014). Effects of Grain Size in Sequential Lateral Solidification Processed on Active Matrix Organic Light Emitting Diode Displays. ECS Solid State Letters, 3(8), R40-R43. https://doi.org/10.1149/2.0071408ssl
  14. K. Shirai, F. Oshiro & T. Noguchi. (2011). Influence of Grain Size Deviation on the Characteristics of Poly-Si Thin Film Transistor. Journal of the Korean Physical Society, 59(2), 298-303. https://doi.org/10.3938/jkps.59.298
  15. G. H. Jin & M. J. Kim. (2009). Effects of gate insulator using high pressure annealing on the characteristics of solid phase crystallized polycrystalline silicon thin-film transistors. Journal of Applied Physics, 105(7), 074507. https://doi.org/10.1063/1.3103335