• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.256-256
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• 2012

Oxide semiconductors such as zinc tin oxide (ZTO) or indium gallium zinc oxide (IGZO) have attracted a lot of research interest owing to their high potential for application as thin film transistors (TFTs) [1,2]. However, the instability of oxide TFTs remains as an obstacle to overcome for practical applications to electronic devices. Several studies have reported that the electrical characteristics of ZnO-based transistors are very sensitive to oxygen, hydrogen, and water [3,4,5]. To improve the reliability issue for the amorphous InGaZnO (a-IGZO) thin-film transistor, back channel passivation layer is essential for the long term bias stability. In this study, we investigated the instability of amorphous indium-gallium-zinc-oxide (IGZO) thin film transistors (TFTs) by the back channel contaminations. The effect of back channel contaminations (humidity or oxygen) on oxide transistor is of importance because it might affect the transistor performance. To remove this environmental condition, we performed vacuum seasoning before the deposition of hybrid passivation layer and acquired improved stability. It was found that vacuum seasoning can remove the back channel contamination if a-IGZO film. Therefore, to achieve highly stable oxide TFTs we suggest that adsorbed chemical gas molecules have to be eliminated from the back-channel prior to forming the passivation layers.

• Transactions on Electrical and Electronic Materials
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• 제17권3호
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• pp.143-145
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• 2016

In order to find suitable source and drain (S/D) electrodes for amorphous InGaZnO thin film transistors (a-IGZO TFTs), the specific contact resistance of interface between the channel layers and various S/D electrodes, such as Ti/Au, a-IZO and multilayer of a-IGZO/Ag/a-IGZO, was investigated using the transmission line model. The a-IGZO TFTs with a-IGZO/Ag/a-IGZO of S/D electrodes had good performance and low contact resistance due to the homo-junction with channel layer. The stability was measured with different electrodes by a positive bias stress test. The result shows the a-IGZO TFTs with a-IGZO/Ag/a-IGZO electrodes were more stable than other devices.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.1586-1589
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• 2009

We investigated the influence of chemical compositions of gallium and indium cations on the performance of solgel derived amorphous gallium indium zinc oxide (a-GIZO) based thin-film transistors (TFTs). Systematical composition study allows us to understand the solutionprocessed a-GIZO TFTs. Understanding of the compositional influence can be utilized for tailoring the solution processed amorphous oxide TFTs for the specific applications.

• 반도체디스플레이기술학회지
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• 제15권1호
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• pp.52-55
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• 2016

GZO film was prepared on p-type Si wafer and then annealed at various temperatures in an air conditions to research the bonding structures in accordance with the annealing processes. GZO film annealed in an atmosphere showed the various bonding structure depending on annealing temperatures and oxygen gas flow rate during the deposition. The difference of bonding structures of GZO films made by oxygen gas flows between 18 sccm and 22 sccm was so great. The bonding structures of GZO films made by oxygen gas flow of 18 sccm were showed the crystal structure, but that of 22 sccm were showed the amorphous structure in spite of after annealing processes. The bonding structure of GZO as oxide-semiconductor was observed the trend of becoming amorphous structures at the temperature of $200^{\circ}C$. Therefore, the characteristics of oxide semiconductor are needed to research the variation near the annealing at $200^{\circ}C$.

• Transactions on Electrical and Electronic Materials
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• 제16권3호
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• pp.139-141
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• 2015

Contact resistance of interface between the channel layers and various S/D electrodes was investigated by transmission line method. Different electrodes such as Ti/Au, a-IZO, and multilayer of a-IGZO/Ag/a-IGZO were compared in terms of contact resistance, using the transmission line model. The a-IGZO TFTs with a-IGZO/Ag/a-IGZO of S/D electrodes showed good performance and low contact resistance due to the homo-junction with channel layer.

• 한국전기전자재료학회논문지
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• 제32권4호
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• pp.272-275
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• 2019

We investigated the electrical characteristics of amorphous silicon-zinc-tin-oxide (a-SZTO) thin films deposited by RF-magnetron sputtering at room temperature depending on the deposition time. We fabricated a thin film transistor (TFT) with a bottom gate structure and various channel thicknesses. With increasing channel thickness, the threshold voltage shifted negatively from -0.44 V to -2.18 V, the on current ($I_{on}$) and field effect mobility (${\mu}_{FE}$) increased because of increasing carrier concentration. The a-SZTO film was fabricated and analyzed in terms of the contact resistance and channel resistance. In this study, the transmission line method (TLM) was adopted and investigated. With increasing channel thickness, the contact resistance and sheet resistance both decreased.

• 반도체디스플레이기술학회지
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• 제14권4호
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• pp.25-29
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• 2015

In this study, RF magnetron sputtering was used to investigate the relationship between oxygen vacancy and carrier concentration in a GZO film on an amorphous structure. RF power was fixed at 50W and Ar flow was changed on a glass plate to create a thin film at room temperature. The transmittance of Al-adopted amorphous GZO was measured at 85% or higher; therefore, the transmittance was shown to be outstanding in all films. The hall mobility was also shown to be higher at the film showing the high transmittance at a short-wavelength, whereas the optical energy gap was shown to be higher at the film with high oxygen vacancy. The oxygen vacancy at the amorphous oxide semi-conductor increased the optical energy gap while it was not directly involved in increasing the mobility. The oxygen vacancy increases the carrier concentration while lowering the quality of amorphous structure; such factor, therefore affected the mobility. The increase of amorphous property is a direct way to increase the mobility of amorphous oxide semi-conductor.

• 한국전기전자재료학회논문지
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• 제27권8호
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• pp.483-485
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• 2014

Transparent amorphous In-Si-O (ISO)/Ag/In-Si-O (ISO) has been reported for low emissivity (low-e) applications. Effective Si doping into the $In_2O_3$ matrix led to a completely amorphous ISO film as well as a low resistivity and a high optical transmittance. The optical and electrical performances were examined by measuring transmittance with a UV-VIS spectrophotometer and resistivity with a Hall effect measurement. Consequently, low-e glass with ISO/Ag/ISO showed a high transparency in the visible region and low emissivity in the infrared region, indicating that ISO is a promising amorphous transparent electrode for low-e glass.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.322-325
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• 2009

Amorphous oxide semiconductors (AOSs) are expected as new channel materials in TFTs for largearea and/or flexible FPDs, and several prototype displays have been demonstrated in these five years since the first report of AOS TFT. In this paper, we review fundamental materials science of AOSs that have been clarified to date in connection with operation characteristics of AOS TFTs.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.35-37
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• 2009

In this work, we introduce new next generation activematrix backplane technologies for large-size AMOLED displays. Among the general requirements for successful market launch of AMOLED TVs, backplane issues are discussed. It will be shown that the amorphous oxide TFT is most suitable due to large scalability and superior cost effectiveness. Development status and current challenges of amorphous oxide TFTs are discussed.