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Adv Sci (Weinh). 2019 Jan 25;6(7):1801189. doi: 10.1002/advs.201801189. eCollection 2019 Apr 3.

Analysis of Ultrahigh Apparent Mobility in Oxide Field-Effect Transistors.

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State Key Lab of Opto-Electronic Materials & Technologies, Guangdong Province Key Lab of Display Material and Technology, School of Electronics and Information Technology, Shunde International Joint Research Institute Sun Yat-Sen University Guangdong 510275 China.
Shenzhen Key Lab of Thin Film Transistor and Advanced Display, Peking University Shenzhen Graduate School Peking University Shenzhen 518055 China.
Department of Applied Biology and Chemical Technology The Hong Kong Polytechnic University Hung Hom Kowloon Hong Kong SAR.
The Hong Kong Polytechnic University Shenzhen Research Institute Shenzhen 518057 China.
Department of Energy and Materials Engineering Dongguk University 30 Pildong-ro, 1 gil, Jung-gu Seoul 04620 Republic of Korea.
International Center for Materials Nanoarchitectonics (WPI-MANA) National Institute for Materials Science (NIMS) Tsukuba Ibaraki 305-0044 Japan.
Department of Physics University of Cambridge Cambridge CB3 1HK UK.


For newly developed semiconductors, obtaining high-performance transistors and identifying carrier mobility have been hot and important issues. Here, large-area fabrications and thorough analysis of InGaZnO transistors with enhanced current by simple encapsulations are reported. The enhancement in the drain current and on-off ratio is remarkable in the long-channel devices (e.g., 40 times in 200 µm long transistors) but becomes much less pronounced in short-channel devices (e.g., 2 times in 5 µm long transistors), which limits its application to the display industry. Combining gated four-probe measurements, scanning Kelvin-probe microscopy, secondary ion mass spectrometry, X-ray photoelectron spectroscopy, and device simulations, it is revealed that the enhanced apparent mobility up to several tens of times is attributed to the stabilized hydrogens in the middle area forming a degenerated channel area while that near the source-drain contacts are merely doped, which causes artifact in mobility extraction. The studies demonstrate the use of hydrogens to remarkably enhance performance of oxide transistors by inducing a new mode of device operation. Also, this study shows clearly that a thorough analysis is necessary to understand the origin of very high apparent mobilities in thin-film transistors or field-effect transistors with advanced semiconductors.


carrier mobility; doping; four‐probe measurement; surface potential scanning; thin‐film transistors

Conflict of interest statement

The authors declare no conflict of interest.

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