Void-Defect Location Control of Laser-Crystallized Silicon Thin Films with Hole-Pattern
Main Article Content
Abstract
High-performance low-temperature polycrystalline silicon (LTPS) thin-film transistors (TFTs) have been developed for larger applications than flat panel displays (FPDs) such as three-dimensional integrated circuits (3D-ICs) and glass sheet computers. The crystallinity of poly-Si thin films has been the key factor determining TFTs’ performance. In this work, a void-defect location has been controlled by patterning amorphous silicon (a-Si) thin films with rectangular and square holes before crystallized by multiline continuous-wave laser beam to avoid the effect of void-defects on the TFTs’ performance. Instead of randomly appearing in the poly-Si thin films, void-defects were only observed at the backsides of the patterned holes. Interestingly, large crystal grains without void-defects were laterally crystallized at Si strips between holes. By observing the crystallinities of poly-Si thin film around the patterned holes, both the mechanism of the void formation and crystal growth based on temperature gradient was clarified.
References
No. 7, 2012, pp. 1018-1020, https://doi.org/10.1109/LED.2012.2196752.
[2] R. Ishihara et al., Single-Grain Si Thin-Film Transistors for Monolithic 3D-ICs and Flexible Electronics. IEICE Trans. Electron, Vol. E97-C, 2014, pp. 227-237, https://doi.org/10.1587/transele.E97.C.227.
[3] S. S. Iyer, Three-dimensional Integration: An Industry Perspective, MRS Bulletin, Vol. 40, 2015, pp. 225-232, https://doi.org/10.1557/mrs.2015.32.
[4] A. Hara, F. Takeuchi, N. Sasaki, Mobility Enhancement Limit of Excimer-Laser-Crystallized Polycrystalline Silicon Thin Film Transistors. J. Appl. Phys., Vol. 91, 2002, pp. 708-714, https://doi.org/10.1063/1.1420766.
[5] M. A. Crowder, A. T. Voutsas, S. R. Droes, M. Moriguchi, Y. Mitani, Sequential Lateral Solidification Processing for Polycrystalline Si TFTs, in IEEE Transactions on Electron Devices, Vol. 51, No. 4, 2004,
pp. 560-568, https://doi.org/10.1109/TED.2004.823795.
[6] W. Zhou et al., Bridged-Grain Solid-Phase-Crystallized Polycrystalline-Silicon Thin-Film Transistors, in IEEE Electron Device Letters, Vol. 33, No. 10, 2012, pp. 1414-1416, https://doi.org/10.1109/LED.2012.2210019.
[7] S. Hayashi et al., Investigation of Silicon Grain Structure and Electrical Characteristics of Tfts Fabricated Using Different Crystallized Silicon Films by Atmospheric Pressure Micro-Thermal-Plasma-Jet Irradiation, Jpn. J. Appl. Phys., Vol. 53, 2014, pp. 03DG02, https://doi.org/10.7567/JJAP.53.03DG02.
[8] A. Hara et al., High-Performance Polycrystalline Silicon Thin Film Transistors on Non-Alkali Glass Produced Using Continuous Wave Laser Lateral Crystallization, Jpn. J. Appl. Phys., Vol. 41, 2002, pp. L311, https://doi.org/10.1143/JJAP.41.L311.
[9] S. I. Kuroki, Y. Kawasaki, S. Fujii, K. Kotani, T. Itob, Seed-Free Fabrication of Highly Bi-Axially Oriented Poly-Si Thin Films by Continuous-Wave Laser Crystallization with Double-Line Beams. J. Electrochem. Soc., Vol. 158, 2011, pp. H924-H930, https://doi.org/10.1149/1.3610410.
[10] T. T. Nguyen, M. Hiraiwa, S. I. Kuroki, Ultrahigh-performance (100)-Oriented Polycrystalline Silicon Thin-Film Transistors and Their Microscopic Crystal Structures, Appl. Phys. Express, Vol. 10, 2017, pp. 056501, https://doi.org/10.7567/APEX.10.056501.
[11] T. T. Nguyen, S. I. Kuroki, Dependence of Thin Film Transistor Characteristics on Low-Angle Grain Boundaries of (100)-Oriented Polycrystalline Silicon Thin Films, Jpn. J. Appl. Phys., Vol. 58, 2019, pp. SBBJ08, https://doi.org/10.7567/1347-4065/ab02e5.
[12] T. T. Nguyen et al., Characterization of Selectively Oriented Polycrystalline Silicon Thin Films Formed by Multiline Beam Continuous-Wave Laser Lateral Crystallization with Overlapping, Jpn. J. Appl. Phys., Vol. 59, 2020, pp. 115504, https://doi.org/10.35848/1347-4065/abc1a9.
[13] J. S. Im, M. Chahal, P. C. V. D. Wilt, U. J. Chung, G. S. Ganot, A. M. Chitu, N. Kobayashi, K. Ohmori,
A. B. Limanov, Mixed-phase Solidification of Thin Si Films on SiO2, J. Cryst. Growth, Vol. 312, 2010,
pp. 2775-2778, https://doi.org/10.1016/j.jcrysgro.2010.05.037.