• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.670-673
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• 2008

Good mechanical properties of thin-film transistors on plastic substrates are an essential parameter in the development of robust flexible displays. In this paper, a careful investigation is carried out on TFT backplane on plastic substrates under cyclic bending conditions. Bending modes of tensile and compressive as well as parallel and perpendicular orientation-dependent bending of channel have been analyzed carefully. This analysis will be helpful in knowing the electro-mechanical performance boundaries of the TFT devices so as to determine the bending limitations of our flexible displays.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.205-207
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• 2008

The new process for hybrid silicon thin film transistor (TFT) using DPSS laser has been developed for realizing both low-temperature poly-Si (LTPS) TFT and a-Si:H TFT on the same substrate as a backplane of active matrix liquid crystal display. LTPS TFTs are integrated on the peripheral area of the panel for gate driver integrated circuit and a-Si:H TFTs are used as a switching device for pixel in the active area. The technology has been developed based on the current a-Si:H TFT fabrication process without introducing ion-doping and activation process and the field effect mobility of $4{\sim}5\;cm^2/V{\cdot}s$ and $0.5\;cm^2/V{\cdot}s$ for each TFT was obtained. The low power consumption, high reliability, and low photosensitivity are realized compared with amorphous silicon gate driver circuit and are demonstrated on the 14.1 inch WXGA+ ($1440{\times}900$) LCD Panel.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.181-185
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• 2006

The flexible 2-inch AMOLED with $176{\times}144$ pixels has been demonstrated using top emission OLED driven by organic thin film transistors (OTFTs). For the development of AMOLED display on plastic substrate, we have developed several integration and unit process technologies. Through the optimization of the process based on plastic substrate, OTFT backplane with 2 transistors and 1 capacitor in a pixel has been fabricated and integrated with top emission OLED. The active addressing by OTFT driving circuit has been achieved and green light with 15 $cd/m^2$ at 15V has been observed.

• Journal of Information Display
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• v.10 no.3
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• pp.131-136
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• 2009

This is a report on the fabrication of a flexible OTFT backplane for electrophoretic display (EPD) using a printing technology. A practical printing technology for a polycarbonate substrate was developed by combining the conventional screen and inkjet printing technologies with the wet etching and oxygen plasma processes. For the gate electrode, the screen printing technology with Ag ink was developed to define the minimum line width of ${\sim}5{\mu}m$ and the thickness of ${\sim}70nm$ with the resistivity of ${\sim}10^{-6}{\Omega}{\cdot}cm$, which are suitable for displays with SVGA resolution. For the source and drain (S/D) electrodes, PEDOT:PSS, whose conductivity was drastically enhanced to 450 S/cm by adding 10 wt% glycerol, was adopted. In addition, the modified PEDOT:PSS could be neatly confined in the specific S/D electrode area that had been pretreated with oxygen. The OTFTs that made use of the developed printing technology produced a mobility of ${\sim}0.13cm^2/Vs.ec$ and an on/off current ratio of ${\sim}10^6$, which are comparable to those using thermally evaporated Au for the S/D electrode.

• 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.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.7
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• pp.81-89
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• 2017

Autofocus(AF) Method is essential to overcome the performance degradation due to motion measurement errors under airborne SAR environment. In this paper, back-projection algorithm(BPA) is applied to SAR raw data acquired under the squinted mode, and preprocessing algorithm of AF for BPA is investigated. To apply AF to SAR image effectively, image backplane rotation method and doppler location alignment function for BPA are proposed. The proposed method is applied to SAR raw data acquired in a flight test and shows excellent performance improvement in real data.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.375-375
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• 2014

Layered semiconductor materials can be a promising candidate for large-area thin film transistors (TFTs) due to their relatively high mobility, low-power switching, mechanically flexibility, optically transparency, and amenability to a low-cost, large-area growth technique like thermal chemical vapor deposition (CVD). Unlike 2D graphene, series of transition metal dichalcogenides (TMDCs), $MX_2$ (M=Ta, Mo, W, X=S, Se, Te), have a finite bandgap (1~2 eV), which makes them highly attractive for electronics switching devices. Recently, 2D $MoS_2$ materials can be expected as next generation high-mobility thin-film transistors for OLED and LCD backplane. In this paper, we investigate in detail the electrical characteristics of 2D layered $MoS_2$ local bottom-gated transistor with the same device structure of the conventional thin film transistor, and expect the feasibility of display application.

• Journal of Information Display
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• v.10 no.4
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• pp.137-142
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• 2009

Transparent top-gate Al-Zn-Sn-O (AZTO) thin-film transistors (TFTs) with an $Al_2O_3$ protective layer (PL) on an active layer were studied, and a transparent 2.5-inch QCIF+AMOLED (active-matrix organic light-emitting diode) display panel was fabricated using an AZTO TFT backplane. The AZTO active layers were deposited via RF magnetron sputtering at room temperature, and the PL was deposited via two different atomic-layer deposition (ALD) processes. The mobility and subthreshold slope were superior in the TFTs annealed in vacuum and with oxygen plasma PLs compared to the TFTs annealed in $O_2$ and with water vapor PLs, but the bias stability of the TFTs annealed in $O_2$ and with water vapor PLs was excellent.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.785-789
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• 2005

Low temperature deposition of silicon and silicon nitride films by catalytic CVD technique was studied for application to thin film transistors on plastic substrates for flexible AMOLEDs. The substrate temperature initially held at room temperature, and was controlled successfully below $150^{\circ}C$ during the entire deposition process. Amorphous silicon films having good adhesion, good surface morphology and sufficiently low content of atomic hydrogen were obtained and could be successfully crystallized using excimer laser without a prior dehydrogenation step. $SiN_x$ films showed a good refractive index, a high deposition rate, a moderate breakdown field and a dielectric constant. The Cat-CVD silicon and silicon nitride films can be good candidates for fabricating thin films transistors on plastic substrates to drive active-matrix organic light emitting display.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.781-784
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• 2005

We have developed technology to fabricate large-size active matrix organic light-emitting diode (AMOLED) displays with good color purity. Using these innovations, we have developed a 40inch diagonal WXGA AMOLED full color display. Because the TFT circuitry occupies a large portion of the pixel structure, an efficient white emission OLED is essential to integrate the device onto the active matrix backplane. The development of these technologies enables OLED displays to fulfill the requirements for larger size applications such as HDTVs