ZnO Thin Film Transistor: Effect of Traps and Grain Boundaries





TCAD simulation, thin film transistor, ZnO, Grain boundary, defects


Recently ZnO has drawn a lot of attention in semiconductor industry due to its interesting features. High exciton binding energy, high resistivity against radiation, high breakdown voltage, low temperature deposition are some of the interesting features of this material. Zinc oxide TFT device gains an increasing interest for its potential in sensing applications due to its biocompability, chemical stability and  simple fabrication process with various methods and high surface-to-volume ratio. However, ZnO TFT devices from previous work exhibited poor ION and field effect mobility. This work investigates the cause of its poor performance by focusing only two factors: traps and defects in the channel and grain boundary. The work was performed in Silvaco TCAD 2D simulator. It was found that a single grain boundary in the channel causes a reduction of the ION by 95%. The effect in the ION is less severe when traps and defects were introduced in the ZnO channel. The results can assist in optimizing the TFT device performance for sensing applications.

Author Biography

Suhana Mohamed Sultan, Universiti Teknologi Malaysia

I am a senior lecturer at the Electronics and Computer Department. I am aslo a member of Computational Nano Electronics Research Group.


P.Lin, F.Yan, “Organic thin-film transistors for chemical and biological sensing,†Adv. Mater. vol. 24, pp. 34-51, 2012.

J. Liu, M. Agarwal, K. Varahramyan, “Glucose sensor based on organic thin film transistor using glucose oxidase and conducting polymer,â€Sensors and Actuators B:Chemical, vol. 135, pp. 195-199, 2008.

E.Fortunato, P.Barquinha and R.Martins, “Oxide Semiconductor Thin-Film Transistors: A Review of Recent Advances,â€Advanced Materials, vol.24, pp.2945-2986, 2012.

Y. Kuo, “Thin film transistor technology--past present and future,†Electrochemical Society Interface, vol.22, pp. 55-61, 2013.

P. I. Reyes, C.-J. Ku, Z. Duan, Y. Lu, A. Solanki and K.-B. Lee, “ZnO thin film transistor immunosensor with high sensitivity and selectivity,†Applied Physics Letters, vol.98, pp. 173702, 2011.

H.-C. Cheng, C.-F. Chen and C.-C. Lee, “Thin-film transistors with active layers of zinc oxide (ZnO) fabricated by low-temperature chemical bath method,†Thin Solid Films, vol.498, pp. 142-145, 2006.

F. M. Hossain, J. Nishii, S. Takagi, A. Ohtomo, T. Fukumura, H. Fujioka, H. Ohno, H. Koinuma and M. Kawasaki, “ Modeling and simulation of polycrystalline ZnO thin-film transistors,†Journal of Applied Physics, vol. 94, pp. 7768-7777, 2003.

Silvaco International, Atlas User’s Manual Device Simulation Software, Silvaco International Ltd., Santa Clara, Dec., (2002).

S. M. Sultan, O. D. Clark, T. Masaud, Q. Fang, R. Gunn, M. Hakim, K. Sun, P. Ashburn and H. M. Chong, “ Remote plasma enhanced atomic layer deposition of ZnO for thin film electronic applications,†Microelectronic Engineering, vol.97, pp. 162-165, 2012.

M. Kimura, S. Inoue, T. Shimoda, and T. Sameshima, Jpn. J. Appl. Phys., Part 1, vol. 40, pp. 49, 2001.

P.Yasaei et al, “Chemical sensing with switchable transport channels in graphene grain boundaries,†Nature Communications, vol.5, Sept 2014.

R.A. Street, “ Thin-Film Transistors,†Adv. Mater. vol.21, pp. 2007-2022, 2009.

K.Vanheusden et al, “Mechanisms behind green photoluminescence in ZnO phosphor powders,†Journal of Applied Physics, vol. 79, pp. 7983-7990, 1996.




How to Cite

Razak, A., Khoo, W., & Mohamed Sultan, S. (2018). ZnO Thin Film Transistor: Effect of Traps and Grain Boundaries. ELEKTRIKA- Journal of Electrical Engineering, 17(1), 41–43. https://doi.org/10.11113/elektrika.v17n1.9