Oxide Electronics Research Team

Daejeon, South Korea

Oxide Electronics Research Team

Daejeon, South Korea
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Yang S.,Oxide Electronics Research Team | Yang S.,Kyung Hee University | Hwang C.-S.,Oxide Electronics Research Team | Lee J.-I.,Oxide Electronics Research Team | And 7 more authors.
Applied Physics Letters | Year: 2011

We have fabricated fully patterned transparent oxide/organic hybrid transistors on glass substrates that contain In-Ga-Zn-O as the active layer and a poly(4-vinyl phenol-comethyl methacrylate) copolymer as the dielectric layer. These devices exhibit a saturation mobility of 6.04cm2 /V s, a threshold voltage value of 3.53 V, a subthreshold slope of 360 mV/decade, and an on-off ratio of 1.0× 109 at a maximum processing temperature of 200 °C. We found that the bias stability characteristics of the hybrid transistors are dependent on the ambient conditions, but can also be dramatically improved by applying a hydrophobic organic passivation layer to the gate insulator. © 2011 American Institute of Physics.


Jin J.,KAIST | Ko J.-H.,KAIST | Seo S.-J.,KAIST | Hwang Y.H.,KAIST | And 7 more authors.
Proceedings of International Meeting on Information Display | Year: 2010

Oxide TFT arrays were fabricated on a low thermal expansion transparent plastic substrate by, so-called GReCoSS process (Glass-fabric Reinforced Coating Films on Surface-treated Substrate). Using this technique, a flexible oxide TFT backplane can be released from a glass carrier plate after the TFT fabrication by a simple de-bonding without using any adhesives, laser release or transfer technique.


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.


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.


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.


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.


Yang S.,Oxide Electronics Research Team | Yang S.,Kyung Hee University | Bak J.Y.,Oxide Electronics Research Team | Bak J.Y.,Kyung Hee University | And 6 more authors.
SID Conference Record of the International Display Research Conference | Year: 2011

We fabricated transparent In-Ga-Zn-O TFTs with topgate structure on glass substrate. The IGZO semiconductors with various compositional ratios were used to compare that effect on bias stability and photon-induced negative bias instability. We found that deep level state in IGZO semiconductors highly affected by In/Ga ratio.


Ryu M.K.,Oxide Electronics Research Team | Park S.-H.K.,Oxide Electronics Research Team | Yang S.H.,Oxide Electronics Research Team | Byun C.-W.,Oxide Electronics Research Team | And 4 more authors.
48th Annual SID Symposium, Seminar, and Exhibition 2010, Display Week 2010 | Year: 2010

We investigated the effect of the light-induced bias instability of indium-gallium-zinc oxide(IGZO) thin film transistors. The IGZO TFT exhibited the excellent subthreshold gate swing of 0.12V/decade, Vth of -0.5V, and high Ion/off ratio of > 109 as well as a high field-effect mobility of 26.7 cm2/Vs. The Vth is not changed after positive bias illumination stress (PBIS) for 10000sec. However, the Vth is -8 V after negative bias illumination stress (NBIS) for 10000sec. This phenomenon can be attributed the trapping of the photon-induced charges into the gate dielectric/active interface. We fabricated transparent AMOLED driven by highly stable bottom gate IGZO TFT array.


Park S.-H.K.,Oxide Electronics Research Team | Ryu M.,Oxide Electronics Research Team | Kim K.,Oxide Electronics Research Team | Yang S.,Oxide Electronics Research Team | And 4 more authors.
Proceedings of International Meeting on Information Display | Year: 2010

We have investigated the effect of active layer thickness in top gate IGZO TFT on the negative bias enhanced photo instability. While the negative bias stability of top gate IGZO TFT was not affected by the active layer thickness in the dark, negative Vth shift is increased with the increase of the active layer thickness under visible white light illumination during negative bias stress. We attributed this much increased negative Vth shift to the increase of donor species as well as the increased positive charge trapping in the gate insulator.

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