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Open AccessArticle

Numerical Analysis on Effective Mass and Traps Density Dependence of Electrical Characteristics of a-IGZO Thin-Film Transistors

1
School of Electronics Engineering, Kyungpook National University, Daegu 41566, Korea
2
Department of Electrical and Computer Engineering, University of Seoul, Seoul 02504, Korea
3
ITODYS CNRS UMR 7086, Université Paris Diderot (Paris7), 15 rue Jean-Antoine de Baïf, CEDEX 13, 75205 Paris, France
*
Author to whom correspondence should be addressed.
Electronics 2020, 9(1), 119; https://doi.org/10.3390/electronics9010119
Received: 10 December 2019 / Revised: 29 December 2019 / Accepted: 6 January 2020 / Published: 8 January 2020
(This article belongs to the Section Semiconductor Devices)
We have investigated the effect of electron effective mass (me*) and tail acceptor-like edge traps density (NTA) on the electrical characteristics of amorphous-InGaZnO (a-IGZO) thin-film transistors (TFTs) through numerical simulation. To examine the credibility of our simulation, we found that by adjusting me* to 0.34 of the free electron mass (mo), we can preferentially derive the experimentally obtained electrical properties of conventional a-IGZO TFTs through our simulation. Our initial simulation considered the effect of me* on the electrical characteristics independent of NTA. We varied the me* value while not changing the other variables related to traps density not dependent on it. As me* was incremented to 0.44 mo, the field-effect mobility (µfe) and the on-state current (Ion) decreased due to the higher sub-gap scattering based on electron capture behavior. However, the threshold voltage (Vth) was not significantly changed due to fixed effective acceptor-like traps (NTA). In reality, since the magnitude of NTA was affected by the magnitude of me*, we controlled me* together with NTA value as a secondary simulation. As the magnitude of both me* and NTA increased, µfe and Ion deceased showing the same phenomena as the first simulation. The magnitude of Vth was higher when compared to the first simulation due to the lower conductivity in the channel. In this regard, our simulation methods showed that controlling me* and NTA simultaneously would be expected to predict and optimize the electrical characteristics of a-IGZO TFTs more precisely. View Full-Text
Keywords: a-IGZO thin-film transistors; effective mass; numerical simulation; electrical characteristics; scattering a-IGZO thin-film transistors; effective mass; numerical simulation; electrical characteristics; scattering
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MDPI and ACS Style

Park, J.; Kim, D.-K.; Park, J.-I.; Kang, I.M.; Jang, J.; Kim, H.; Lang, P.; Bae, J.-H. Numerical Analysis on Effective Mass and Traps Density Dependence of Electrical Characteristics of a-IGZO Thin-Film Transistors. Electronics 2020, 9, 119.

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