AN AMORPHOUS SILICON PHOTO TFT WITH SI3N4/AL2O3 OR HFO2 DOUBLE LAYERED INSULATOR FOR DIGITAL IMAGING APPLICATIONS

Authors

  • Siham Belkacemi
  • Zoubeida Hafdi

DOI:

https://doi.org/10.1590/2179-10742019v18i11464

Keywords:

a-Si:H TFT, Al2O3, External Quantum Efficiency, HfO2, Photocurrent, Responsivity, Si3N

Abstract

This paper focuses on amorphous silicon photo thin-film transistors with double layered insulator using Si3N4/Al2O3 or HfO2 as candidates for the succession of Si3N4 as a traditional insulator in the fabrication of hydrogenated amorphous silicon thin-film transistors. Whether for industry or for research, there is a need to investigate the use of thin gate insulators for these devices to overcome leakage current. Our investigations included direct and transfer characteristics in dark and under illumination, generated photocurrents, external quantum efficiency and responsivity. Performance is evaluated in terms of the dielectric thickness and nature. Improvements in the proposed structures regarding off-current, responsivity and quantum efficiency are achieved via these materials. Comparing with Si3N4/HfO2 transistor, the Si3N4/Al2O3 device shows the lowest off-current. The HfO2 device presents the highest on-current when illuminated. The generated photocurrent is higher for Si3N4/HfO2 transistor revealing a lower amount of trapped charge. Under illumination and for very thin thicknesses, both devices enhance the Si3N4 device off-current and reach Si3N4 single layer dielectric based phototransistor performance. external quantum efficiency and responsivity are higher in HfO2 devices comparing with Al2O3 devices. The results are promising and may support further investigations in order to develop high k gate insulators for MIS photo thin-film transistors.

References

[1] K. Rosan, "Hydrogenated Amorphous-Silicon Image Sensors," IEEE Transactions on Electron Devices, vol. 36, no. 12,
pp. 2923-2927, 1989.
[2] M. Yamaguchi, Y. Kaneko, and K. Tsutsui. "Two-Dimensional Contact-Type Image Sensor Using Amorphous Silicon
Photo-Transistor," Japanese Journal of Applied Physics, vol. 32, no. 1B, pp. 458, 1993.
[3] Z. Hafdi, "An Analytical Capacitance Model for a Hydrogenated Amorphous Silicon Based Thin-Film Transistor,"
Physics Procedia, vol. 21, pp. 122-127, 2011.
[4] L. Wang, H. Ou, J. Chen, and K. Wang, "A Numerical Study of an Amorphous Silicon Dual-Gate Photo Thin-Film
Transistor for Low-Dose X-Ray Imaging," Journal of Display Technology, vol. 11, no. 8, pp. 646-651, 2015.
[5] Rahn, F. Lemmi, J. Lu, P. Mei, R. Apte, R. Street, R. Lujan, R. Weisfield, and J. Heanue, "High Resolution X-Ray
Imaging Using Amorphous Silicon Flat-Panel Arrays," in Nuclear Science Symposium, 1998. Conference Record. 1998
IEEE, vol. 2. IEEE, pp. 1073-1077, 1998.
[6] S. M. GadelRab and S. G. Chamberlain, "The Source-Gated Amorphous Silicon Photo-Transistor," IEEE Transactions
on Electron Devices, vol. 44, no. 10, pp. 1789-1794, 1997.
[7] Y. Vygranenko, A. Nathan, M. Vieira, and A. Sazonov, "Phototransistor with Nanocrystalline Si/Amorphous Si Bilayer
Channel," Applied Physics Letters, vol. 96, no. 17, pp. 173507, 2010.
[8] K. Wang, H. Ou, and J. Chen, "Dual-Gate Photosensitive Thin-Film Transistor-Based Active Pixel Sensor for IndirectConversion X-Ray Imaging," IEEE Transactions on Electron Devices, vol. 62, no. 9, pp. 2894-2899, 2015.
[9] M. Yamaguchi, Y. Kaneko, and K. Tsutsui, "Two-Dimensional Contact-Type Image Sensor Using Amorphous Silicon
Photo-Transistor," Japanese Journal of Applied Physics, vol. 32, no. 1B, pp. 458, 1993.
[10] S. Martin, C.-S. Chiang, J.-Y. Nahm, T. Li, J. Kanicki, and Y. Ugai, "Influence of the Amorphous Silicon Thickness on
Top Gate Thin-Film Transistor Electrical Performances," Japanese Journal of Applied Physics, vol. 40, no. 2A, pp. 530,
2001.
[11] S. Ghanbarzadeh, S. Abbaszadeh, and K. S. Karim, "Low Dark Current Amorphous Silicon Metal-SemiconductorMetal Photodetector for Digital Imaging Applications," IEEE Electron Device Letters, vol. 35, no. 2, pp. 235-237, 2014.
[12] Y. Kaneko, N. Koike, K. Tsutsui, and T. Tsukada, "Amorphous Silicon Phototransistors," Applied Physics Letters, vol.
56, no. 7, pp. 650-652, 1990.
[13] Z. Hafdi and M. S. Aida, "Modeling and Simulation of Hydrogenated Amorphous Silicon Thin-Film Transistors,"
Japanese Journal of Applied Physics, vol. 44, no. 3, pp. 1192-1198, 2005.
[14] Z. Hafdi, "Design Considerations of an Amorphous Silicon Demultiplexer," Elektronika ir Elektrotechnika, Vol. 19,
No. 8, pp. 65-68, 2013.
[15] H. Yamamoto, H. Matsumaru, K. Shirahashi, M. Nakatani, A. Sasano, N. Konishi, K. Tsutsui, and T. Tsukada, "A New
a-Si TFT With Al2O3/SiN Double-Layered Gate Insulator for 10.4-Inch Diagonal Multicolor Display," in Electron
Devices Meeting, 1990. IEDM'90. Technical Digest., International. IEEE, pp. 851-854, 1990.
[16] C.-S. Ho, S.-J. Chang, S.-C. Chen, J. J. Liou, and H. Li, "A Reliable Si3N4/Al2O3-HfO2 Stack MIM Capacitor for HighVoltage Analog Applications," IEEE Transactions on Electron Devices, vol. 61, no. 8, pp. 2944-2949, 2014.
[17] Y. Wu, M. Xu, Y. Xuan, P. Ye, J. Li, Z. Cheng, and A. Lochtefeld, "Inversion-Type Enhancement-Mode InP Mosfets
with ALD High-K Al2O3 and HfO2 as Gate Dielectrics," in University/Government/Industry Micro/Nano Symposium,
2008. UGIM 2008. 17th Biennial. IEEE, pp. 49-52, 2008..
[18] J. Robertson, "High Dielectric Constant Gate Oxides for Metal Oxide Si Transistors," Reports on Progress in Physics,
vol. 69, no. 2, p. 327, 2005.
[19] G. Roll, J. Mo, E. Lind, S. Johansson, and L.-E. Wernersson, "Defect Evaluation in InGaAs Field Effect Transistors
with HfO2 or Al2O3 Dielectric," Applied Physics Letters, vol. 106, no. 20, p. 203503, 2015.
[20] Y. Kuo, Thin film transistors. 1. Amorphous silicon thin film transistors. Springer Science & Business Media, 2004,
vol. 1.
[21] K. Hiranaka, T. Yoshimura, and T. Yamaguchi, "Effects of The Deposition Sequence on Amorphous Silicon Thin-Film
Transistors," Japanese Journal of Applied Physics, vol. 28, no. part 1, pp. 2197-2200, 1989.
[22] F. Taghibakhsh, I. Khodami, and K. S. Karim, "Characterization of Short-Wavelength-Selective a-Si:H MSM
Photoconductors for Large-Area Digital-Imaging Applications," IEEE Transactions on Electron Devices, vol. 55, no. 1,
pp. 337-342, 2008.
[23] I. Silvaco, "Atlas User's Manual Device Simulation Software," 2010.
[24] Y.-T. Tsai, K.-D. Hong, and Y.-L. Yuan, "An Efficient Analytical Model for Calculating Trapped Charge in
Amorphous Silicon," IEEE transactions on computer-aided design of integrated circuits and systems, vol. 13, no. 6, pp.
725-728, 1994.
[25] G. S. Risti_c, "The Digital Flat-Panel X-Ray Detectors," in Conference on Medical Physics And Biomedical
Engineering, p. 65, 2013.
[26] M. R. Esmaeili-Rad, N. P. Papadopoulos, M. Bauza, A. Nathan, and W. S. Wong, "Blue-Light-Sensitive Phototransistor
for Indirect X-Ray Image Sensors," IEEE Electron Device Letters, vol. 33, no. 4, pp. 567-569, 2012.
[27] M. Grodzicka, M. Moszynski, T. Szczesniak, M. Szawlowski, D. Wolski, and J. Baszak, "MPPC Array in the Readout
of CsI:Tl, LSO:Ce:Ca, LaBr3:Ce, and BGO Scintillators," IEEE Transactions on Nuclear Science, vol. 59, no. 6, pp.
3294-3303, 2012.
[28] E. Takeda, T. Kawaguchi, Y. Nanno, N. Tsutsu, T. Tamura, S.-i. Ishihara, and S. Nagata, "An Amorphous Si TFT Array
with TaOx/SiNx Double Layered Insulator for Liquid Crystal Displays," in Display Research Conference, 1988,
Conference Record of the 1988 International. IEEE, pp. 155-158, 1988.
[29] Y. Lee, I. Omkaram, J. Park, H.-S. Kim, K.-U. Kyung, W. Park, and S. Kim, "A a-Si:H Thin-Film Phototransistor for a
Near-Infrared Touch Sensor," IEEE Electron Device Letters, vol. 36, no. 1, pp. 41-43, 2015.
[30] S. D. Ganichev, A. P. Dmitriev, S. A. Emel'yanov, Ya. V. Terent'ev, I. D. Yaroshetskii, and I. N. Yassievich, "Impact
ionization in semiconductors under the influence of the electric field of an optical wave," Soviet Physics—JETP, vol.
63, no. 2, pp. 445-457, 1986.
[31] C. -H. Lin, C. W. Liu, "Metal-insulator-semiconductor photodetectors," Sensors, vol. 10, no 10, pp. 8797-8826, 2010.
[32] Z. Hafdi, "Surface States in Amorphous Silicon Thin-Film Transistors: Modeling and Impact," World Applied Sciences
Journal, vol. 31, pp. 63-68, 2014.
[33] L. Kuan-Ting, C. Feng-Tso, "High performance raised source/drain thin film transistor with field plate design," In
: Active-Matrix Flat panel Displays and Devices (AM-FPD), 2014 21st International Workshop on. IEEE, pp. 335-338,
2014.
[34] Y. Kaneko, N. Koike, K. Tsutsui, T. Sukada, "Amorphous silicon phototransistors," Applied Physics Letters, vol. 56,
no.7, pp. 650-652, 1990.

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Published

2020-04-09

How to Cite

Siham Belkacemi, & Zoubeida Hafdi. (2020). AN AMORPHOUS SILICON PHOTO TFT WITH SI3N4/AL2O3 OR HFO2 DOUBLE LAYERED INSULATOR FOR DIGITAL IMAGING APPLICATIONS. Journal of Microwaves, Optoelectronics and Electromagnetic Applications (JMOe), 18(1), 43–69. https://doi.org/10.1590/2179-10742019v18i11464

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