• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.7
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• pp.437-440
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• 2017

We report on amorphous thin-film transistors (TFTs) with indium zinc oxide (IZO) channel layers that were fabricated via a solution process. We prepared the IZO semiconductor solution with 0.1 M indium nitrate hydrate and 0.1 M zinc acetate dehydrate as precursor solutions. The solution- processed IZO TFTs showed good performance: a field-effect mobility of $7.29cm^2/Vs$, a threshold voltage of 4.66 V, a subthreshold slope of 0.48 V/dec, and a current on-to-off ratio of $1.62{\times}10^5$. To investigate the static response of our solution-processed IZO TFTs, simple resistor load-type inverters were fabricated by connecting a $2-M{\Omega}$ resistor. Our IZOTFTbased N-MOS inverter performed well at operating voltage, and therefore, isa good candidate for advanced logic circuits and display backplane.

• Transactions on Electrical and Electronic Materials
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• v.11 no.6
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• pp.253-256
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• 2010

Different active layer thicknesses for zinc oxide (ZnO) bottom-contact thin-film transistors (TFTs) were fabricated with a poly-4-vinyphenol polymeric dielectric using injector type atomic layer deposition. The properties of the ZnO TFTs were influenced by the active thickness and width-to-length (W/L) ratio of the device. The threshold voltage of ZnO TFTs shifted positively as the active layer thickness decreased, while the subthreshold slope decreased. The W/L ratio of ZnO TFTs also affected the mobility and subthreshold slope. An optimized TFT structure exhibited an on-tooff current ratio of above 106 with solid saturation.

• Electrical & Electronic Materials
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• v.8 no.6
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• pp.693-698
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• 1995

We fabricated Zinc Oxide transparent conductive thin films with 2wt% of A1203 doping using rf magnetron sputtering. And we investigated electrical and optical characteristics of them which were made with conditions ; rf power 60-300W, thickness of film 3000 11000.angs.. Resistivity, carrier concentration and Hall mobility were investigated for electrical characteristics. Transmittance and optical band gap were investigated with Spectrophotometer in the wavelength range between 200-900 nm. As a result, ZnO thin film fabricated with rf power of 180W and thickness of 5000.angs. showed the best properties. At the best condition, the sample has resistivity of 1*10$\^$-4/.ohm.cm and transmittance of 95% in the visible range.

• Journal of the Korean institute of surface engineering
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• v.33 no.4
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• pp.229-232
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• 2000

C-axis oriented zinc oxide thin films were deposited on glass substrate by reactive Facing Targets Sputtering (FTS) system. The characteristics of zinc oxide thin films on power, inter targets distance, and substrate temperature were investigated by XRD(x-ray diffractometer), alphastep (Tencor) analyses. The Facing Targets Sputtering system can deposit thin film in plasma-free situation and change the deposition condition in wide range. The excellently c-axis oriented zinc oxide thin films were obtained at sputter pressure 1mTorr, sputtering current 0.4A, substrate temperature $300^{\circ}C$, inter targets distance 100mm. In the conditions, the rocking curve of zinc oxide thin films deposited on ZnO/Glass was $3.9^{\circ}$.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.215-219
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• 2007

In this work, the indium zinc oxide (IZO) films had been deposited on the glass substrate coated with the SiO film. Based on a comparative investigation of the IZO monolayer and IZO/SiO multilayer, it is shown that the thickness of SiO film has a great effect on the mechanical properties of the thin films. The AFM images of the IZO thin film included the SiO film were shown smoother surfaces than monolayer. Resistivity was in inverse proportion to Mobility. If it deposited the SiO film on the substrate, the layer of change was generated between two layer(SiO and substrate). The layer of change influenced resistance because of oxygen content was more than the IZO monolayer.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.373-373
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• 2012

We fabricated conductive zinc oxide (ZnO) thin film at low temperature by UV-enhanced atomic layer deposition. The atomic layer deposition relies on alternate pulsing of the precursor gases onto the substrate surface and subsequent chemisorption of the precursors. In this experiment, diethylzinc (DEZ) and $H_2O$ were used as precursors with UV light. The UV light was very effective to improve the conductivity of the ZnO thin film. The thickness, transparency and resistivity were investigated by ellisometry, UV-visible spectroscopy and Four-point probe.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.6
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• pp.401-405
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• 2017

Because silicon thin film solar cells have a high absorption coefficient in visible light, they can absorb 90% of the solar spectrum in a $1-{\mu}m$-thick layer. Silicon thin film solar cells also have high transparency and are lightweight. Therefore, they can be used for building integrated photovoltaic (BIPV) systems. However, the contact electrode needs to be replaced for fabricating silicon thin film solar cells in BIPV systems, because most of the silicon thin film solar cells use metal electrodes that have a high reflectivity and low transmittance. In this study, we replace the conventional aluminum top electrode with a transparent aluminum-doped zinc oxide (AZO) electrode, the band level of which matches well with that of the intrinsic layer of the silicon thin film solar cell and has high transmittance. We show that the AZO effectively replaces the top metal electrode and the bottom fluorine-doped tin oxide (FTO) substrate without a noticeable degradation of the photovoltaic characteristics.

• Transactions on Electrical and Electronic Materials
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• v.14 no.2
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• pp.59-62
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• 2013

At an infra-red (IR) wavelength of 1,064 nm, a diode-pumped Q-switched $Nd:YVO_4$ laser was used for the direct patterning of various transparent conductive oxide (TCO) thin films on glass substrate. With various laser beam conditions, the laser ablation results showed that the indium tin oxide (ITO) film was removed completely. In contrast, zinc oxide (ZnO) film was not etched for any laser beam conditions and indium gallium zinc oxide (IGZO) was only ablated with a low scanning speed. The difference in laser ablation is thought to be due to the crystal structures and the coefficient of thermal expansion (CTE) of ITO, IGZO, and ZnO. The width of the laser-patterned grooves was dependent on the film materials, the repetition rate, and the scanning speed of the laser beam.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.252-253
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• 2011

ZnO-based thin film transistors (TFTs) are of great interest for application in next generation flat panel displays. Most research has been based on amorphous indium-gallium-zinc-oxide (IGZO) TFTs, rather than single binary oxides, such as ZnO, due to the reproducibility, uniformity, and surface smoothness of the IGZO active channel layer. However, recently, intrinsic ZnO-TFTs have been investigated, and TFT- arrayss have been demonstrated as prototypes of flat-panel displays and electronic circuits. However, ZnO thin films have some significant problems for application as an active channel layer of TFTs; it was easy to change the electrical properties of the i-ZnO thin films under external conditions. The variable electrical properties lead to unstable TFTs device characteristics under bias stress and/or temperature. In order to obtain higher performance and more stable ZnO-based TFTs, HZO thin film was used as an active channel layer. It was expected that HZO-TFTs would have more stable electrical characteristics under gate bias stress conditions because the binding energy of Hf-O is greater than that of Zn-O. For deposition of HZO thin films, Hf would be substituted with Zn, and then Hf could be suppressed to generate oxygen vacancies. In this study, the fabrication of the oxide-based TFTs with HZO active channel layer was reported with excellent stability. Application of HZO thin films as an active channel layer improved the TFT device performance and bias stability, as compared to i-ZnO TFTs. The excellent negative bias temperature stress (NBTS) stability of the device was analyzed using the HZO and i-ZnO TFTs transfer curves acquired at a high temperature (473 K).

• Proceedings of the Materials Research Society of Korea Conference
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• 2007.11a
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• pp.52.1-52.1
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• 2007