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Daejeon, South Korea

Yu K.M.,Hoseo University | Moon H.J.,Hoseo University | Ryu M.K.,Oxide Electronics Research Team | Cho K.I.,Oxide Electronics Research Team | And 2 more authors.
Japanese Journal of Applied Physics | Year: 2012

Under white light illumination, amorphous indium-gallium-zinc oxide (a-IGZO)-based thin-film transistors (TFTs) showed a large negative shift of threshold voltage of more than - 15 V depending on the process conditions. We investigated the influences of both gate bias and white light illumination on device properties of IGZO-based TFTs untreated and treated with high-energy electron beam irradiation (HEEBI). The TFTs were treated with HEEBI in air at room temperature (RT), electron beam energy of 0.8 MeV, and a dose of 1 × 10 14 electrons/cm 2. The HEEBI-treated TFTs showed an improved stability under negative bias illumination stress (NBIS) and positive bias illumination stress (PBIS) compared with non- HEEBI-treated TFTs, suggesting that the acceptor-like defects might be generated by HEEBI treatment near the valence band edge. © 2012 The Japan Society of Applied Physics.

Yu K.M.,Hoseo University | Yuh J.T.,Kent State University | Park S.H.K.,Oxide Electronics Research Team | Ryu M.K.,Oxide Electronics Research Team | And 2 more authors.
Japanese Journal of Applied Physics | Year: 2013

We investigated the temperature dependent recovery of the threshold voltage shift observed in both ZnO and indium gallium zinc oxide (IGZO) thin film transistors (TFTs) after application of gate bias and light illumination. Two types of recovery were observed for both the ZnO and IGZO TFTs; low temperature recovery (below 110°C) which is attributed to the trapped charge and high temperature recovery (over 110 °C) which is related to the annihilation of trap states generated during stresses. From a comparison study of the recovery rate with the analysis of hydrogen diffusion isochronal annealing, a similar behavior was observed for both TFT recovery and hydrogen diffusion. This result suggests that hydrogen plays an important role in the generation and annihilation of trap states in oxide TFTs under gate bias or light illumination stresses. © 2013 The Japan Society of Applied Physics.

Hwang Y.H.,Korea Electronics Technology Institute | Seo J.-S.,Korea Advanced Institute of Science and Technology | Yun J.M.,Korea Advanced Institute of Science and Technology | Park H.,Korea Advanced Institute of Science and Technology | And 3 more authors.
NPG Asia Materials | Year: 2013

Metal-oxide semiconductors have attracted considerable attention as next-generation circuitry for displays and energy devices because of their unique transparency and high performance. We propose a simple, novel and inexpensive 'aqueous route' for the fabrication of oxide thin-film transistors (TFTs) at low annealing temperatures (that is, <200 °C). These results provide substantial progress toward solution-processed metal-oxide TFTs through naturally formed, unique indium complex and post annealing. The fabricated TFTs exhibited acceptable electrical performance with good large-area uniformity at low temperatures. Additional vacuum annealing facilitated the condensation reaction by effectively removing byproduct water molecules and resulted in the activation of the In2O3 TFT at low annealing temperatures, even temperatures as low as 100 °C. In addition, we have demonstrated that the flexible and transparent oxide TFTs on plastic substrates exhibit good resistance to external gate bias stress. © 2013 Nature Japan K.K.

Cheong W.-S.,Oxide Electronics Research Team | Lee M.-H.,Oxide Electronics Research Team | Bak J.-Y.,Oxide Electronics Research Team | Chung S.M.,Oxide Electronics Research Team | And 3 more authors.
Proceedings of International Meeting on Information Display | Year: 2010

Transparent electronic materials have been fabricated by ionized physical vapor deposition method. Properties of TCOs and oxide semiconductors were greatly affected by the electron density of plasma, which could provide a clue for obtaining high performance thin films.

Park S.-H.K.,Oxide Electronics Research Team | Ryu M.-K.,Oxide Electronics Research Team | Yoon S.-M.,Oxide Electronics Research Team | Yang S.,Oxide Electronics Research Team | And 2 more authors.
Journal of the Society for Information Display | Year: 2010

The stability of oxide TFTs has been the main focus of this research and is probably the most crucial requ irement for the successful application to flat-panel displays. Although the high Fermi level of oxide semiconductors makes TFTs basically stable under electrical stress, the device reliability under diverse variations of electrical stress is affected by materials such as active semiconductors and gate insulators, processes for the formation of back/front channels and passivation layers, and device configurations among other things. How these factors affect the device reliability have been investigated and a review of the stability is presented. In addition, several categories of the light instability of oxide TFTs is presented and the origin is discussed. © Copyright 2010 Society for Information Display.

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