• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.406-407
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• 2007

We prepared indium zinc oxide (IZO) thin film for cathode electrode such as an application of flat panel display by using the facing targets sputtering (FTS) method at room temperature. The effects of input power and film thickness were investigated with respect to physical and optical properties of films such as deposition rate, electrical properties, microstructure and transmittance. We could obtain properties of IZO thin films of under $10^{-3}\;{\Omega}-cm$ in resistivity and the thin films of over 90% in transmittance. Also, we obtained IZO thin films which were an amorphous structure.

• Transactions on Electrical and Electronic Materials
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• v.7 no.5
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• pp.271-275
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• 2006

Al oped zinc oxide (AZO) films were prepared by Facing Targets Sputtering (FTS) system for TCO applications. The electrical, optical and structural properties of AZO thin films have been investigated with input current, oxygen gas flow ratio and substrate temperature. Deposition was carried out at room temperature and $200^{\circ}C$. Working gas pressures were fixed at 1mTorr. As a result, AZO thin film deposited with an optical transmittance over 80 % and a resistivity about $10^{-4}{Omega}{\cdot}cm$.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.1081-1081
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• 2002

Top emission organic EL devices were fabricated by using metal-doped cathode interface layer to achieve low drive voltages. Also, facing-targets-type sputtering was used to sputter indium-tin oxide layer on top of organic active layer. The devices fabricated in this study showed reasonably high external quantum efficiency of about 1 % which is comparable to that of bottom-emission-type devices.

• Korean Journal of Materials Research
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• v.19 no.1
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• pp.24-27
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• 2009

Indium Gallium Zinc Oxide (IGZO) thin films were deposited onto 300 nm-thick oxidized Si substrates and glass substrates by direct current (DC) magnetron sputtering of IGZO targets at room temperature. FESEM and XRD analyses indicate that non-annealed and annealed IGZO thin films exhibit an amorphous structure. To investigate the effect of an annealing treatment, the films were thermally treated at $300^{\circ}C$ for 1hr in air. The IGZO TFTs structure was a bottom-gate type in which electrodes were deposited by the DC magnetron sputtering of Ti and Au targets at room temperature. The non-annealed and annealed IGZO TFTs exhibit an $I_{on}/I_{off}$ ratio of more than $10^5$. The saturation mobility and threshold voltage of nonannealed IGZO TFTs was $4.92{\times}10^{-1}cm^2/V{\cdot}s$ and 1.46V, respectively, whereas these values for the annealed TFTs were $1.49{\times}10^{-1}cm^2/V{\cdot}$ and 15.43V, respectively. It is believed that an increase in the surface roughness after an annealing treatment degrades the quality of the device. The transmittances of the IGZO thin films were approximately 80%. These results demonstrate that IGZO thin films are suitable for use as transparent thin film transistors (TTFTs).

• Proceedings of the KIEE Conference
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• 2005.11a
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• pp.62-64
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• 2005

Indium Tim Oxide(ITO) thin film was prepared for TOLEDs by Facing Targets Sputtering(FTS) apparatus which can suppress the damage of organic layer due to the collisions of high energetic particles. In particular, ITO thin film was prepared with changing the distance between two targets for reduced the bombardment by high energetic particles such as ${\gamma}-electron$ or negative oxygen ions. The electrical and optical properties of ITO thin films as a function of distance of between two targets were measured. Additionally, the ITO thin films were prepared on the cell (cell : MgAg/LiF/EML/HTL/ bottom electrode) with distance of between two targets. And the I-V characteristics of ITO/cell was investigated.

• Proceedings of the KIEE Conference
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• 2000.11c
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• pp.509-510
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• 2000

Piezoelectric ZnO thin films were deposited on slide glass by Facing Targets Sputtering(FTS). The Facing Targets Sputtering system can deposit thin film in plasma-free situation and change the deposition condition in wide range. The characteristics of zinc oxide thin films on power, working pressure, and substrate temperature were investigated by XRD (x-ray diffractometer), alpha-step (Tencor) and SEM (Scanning Electron Microscopy) analyses. In the results, we suggest that FTS system is very suitable to preparing high quality ZnO thin films with good c-axis orientation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.361-364
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• 2000

Antimony doped tin oxide (ATO) thin films were deposited at room temperature by reactive ion-beam sputter deposition (IBSD) technique in oxidizing atmosphere utilizing Sb and Sn metal targets. Effect of Sb doping concentration, film thickness and heat treatment on electrical and optical properties was investigated. The thickness of as-deposited films was controlled approximately to 1500 $\AA$ or 2000$\AA$, and Sb concentration to 10.8 and 14.9 wt%, as determined by SEM and XPS analyses. Heat treatment was performed at the temperature from 40$0^{\circ}C$ to 80$0^{\circ}C$ in flowing $O_2$or forming gas. The resulting ATO films showed widely changing electrical resistivity and optical transmittance values in the visible spectrum depending on the composition, thickness and firing condition.

• Journal of the Korean institute of surface engineering
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• v.40 no.3
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• pp.107-112
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• 2007

Aluminum doped zinc oxide (AZO) films were deposited on non-alkali glass substrate by DC magnetron sputtering with 3 types of AZO targets (doped with 1.0 wt%, 2.0 wt%, 3.0 wt% $Al_2O_3$). Electrical, optical properties and microstructure of AZO films have been investigated by Hall effect measurements, UV/VIS/NIR spectrophotometer, and XRD, respectively. Crystallinity of AZO films increased with increasing substrate temperature ($T_s$) and doping ratio of Al. Resistivity and optical transmittance in visible light were $8.8{\times}10^{-4}{\Omega}cm$ and above 85%, respectively, for the AZO film deposited using AZO target (doped with 3.0 wt% $Al_2O_3$) at $T_s$ of $300^{\circ}C$. On the other hand, transmittance of AZO films in near-infrared region decreased with increasing $T_s$ and doping ratio of Al, which could be attributed to the increase of carrier density.

• Journal of the Korean institute of surface engineering
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• v.42 no.6
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• pp.267-271
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• 2009

Multicomponent transparent conducting oxide films were deposited on glass substrates at 150 by dual magnetron sputtering of AZO and ITO targets. In the case of mixing a limited amount of ITO (10W), resistivity of TCO films was significantly increased compared to the AZO film; from $3.5{\times}10^{-3}$ to $9.7{\times}10^{-3}{\Omega}{\cdot}cm$. Deterioration of the electrical conductivity is attributed to the decreases in carrier concentration and Hall mobility. Improvement of the conductivity could be obtained for the films prepared with ITO powers larger than 40 W. The lowest resistivity ($\rho$) of $7.3{\times}10^{-4}{\Omega}{\cdot}cm$ was achieved when ITO power was 100 W. Effects of $H_2$ incorporation on the electrical and optical properties of AZO-ITO films were investigated in this work. Addition of small amount of hydrogen resulted in the increase of carrier concentration and the improvement of electrical conductivity. It is apparent that the roughness of AZO-ITO films decreases dramatically after the transition of microstructure from polycrystalline to amorphous phase, which gives practical advantages such as an excellent uniformity of surface and a high etching rate. AZO-ITO films grown at sputtering ambient with hydrogen gas are expected to be applicable to optoelectronic devices such as organic light emitting diodes and flexible displays due to their sufficient electrical and structural properties.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.334-334
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• 2012

Transparent oxide semiconductors have recently attracted much attention as channel layer materials due to advantageous electrical and optical characteristics such as high mobility, high stability, and good transparency. In addition, transparent oxide semiconductor can be fabricated at low temperature with a low production cost and it permits highly uniform devices such as large area displays. A variety of thin film transistors (TFTs) have been studied including ZnO, InZnO, and InGaZnO as the channel layer. Recently, there are many studies for substitution of Ga in InGaZnO TFTs due to their problem, such as stability of devices. In this work, new quaternary compound materials, tantalum-indium-tin oxide (TaInSnO) thin films were fabricated by using co-sputtering and used for the active channel layer in thin film transistors (TFTs). We deposited TaInSnO films in a mixed gas (O2+Ar) atmosphere by co-sputtering from Ta and ITO targets, respectively. The electric characteristics of TaInSnO TFTs and thin films were investigated according to the RF power applied to the $Ta_2O_5$ target. The addition of Ta elements could suppress the formation of oxygen vacancies because of the stronger oxidation tendency of Ta relative to that of In or Sn. Therefore the free carrier density decreased with increasing RF power of $Ta_2O_5$ in TaInSnO thin film. The optimized characteristics of TaInSnO TFT showed an on/off current ratio of $1.4{\times}108$, a threshold voltage of 2.91 V, a field-effect mobility of 2.37 cm2/Vs, and a subthreshold swing of 0.48 V/dec.