• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.12
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• pp.25-35
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• 2001

In order to analyze the electrical characteristics of complicated thin film transistor-liquid crystal display (TFT-LCD) array circuits, it is indispensible to use simulation programs such as PSPICE and AIM-SPICE. In this paper, we present a systematic method of extracting the input parameters of poly-Si TFT for SPICE simulations. This method was applied to two different types of poly-Si TFTs, fabricated by excimer laser annealing and silicide mediated crystallization methods, and yielded good fitting results to experimental data. Among the SPICE simulators, PSPICE has the graphic user interface feature making the composition of complicated circuits easier. We added successfully a poly-Si TFT device model to the PSPICE simulator, and analyzed easily the electrical characteristics of pixels considering the line RC delay. The results of this work would contribute to efficient simulations of poly-Si TFT-LCD arrays.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.221-221
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• 2013

Striving to replace the well known silicon nanocrystals embedded in oxides with solution-processable charge-trapping materials has been debated because of large scale and cost effective demands. Herein, a silicon quantum dot-polystyrene nanocomposite (SiQD-PS NC) was synthesized by postfunctionalization of hydrogen-terminated silicon quantum dots (H-SiQDs) with styrene using a thermally induced surface-initiated polymerization approach. The NC contains two miscible components: PS and SiQD@PS, which respectively are polystyrene and polystyrene chains-capped SiQDs. Spin-coated films of the nanocomposite on various substrate were thermally annealed at different temperatures and subsequently used to construct metal-insulator-semiconductor (MIS) devices and thin film field effect transistors (TFTs) having a structure p-$S^{++}$/$SiO_2$/NC/pentacene/Au source-drain. C-V curves obtained from the MIS devices exhibit a well-defined counterclockwise hysteresis with negative fat band shifts, which was stable over a wide range of curing temperature ($50{\sim}250^{\circ}C$. The positive charge trapping capability of the NC originates from the spherical potential well structure of the SiQD@PS component while the strong chemical bonding between SiQDs and polystyrene chains accounts for the thermal stability of the charge trapping property. The transfer curve of the transistor was controllably shifted to the negative direction by chaining applied gate voltage. Thereby, this newly synthesized and solution processable SiQD-PS nanocomposite is applicable as charge trapping materials for TFT based memory devices.

• Journal of the Microelectronics and Packaging Society
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• v.16 no.4
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• pp.17-22
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• 2009

Two different organic-inorganic hybrid thin film transistors (OITFTs) with the structures of glass/ITO/ZnO/PMMA/Al (staggered structure) and glass/ITO/PMMA/ZnO/Al (inverted staggered structure), were fabricated and their electrical and structural properties were compared. The ZnO thin films used as active channel layers were deposited by the atomic layer deposition (ALD) method at a temperature of $100^{\circ}C$. To investigate the effect of the substrates on their properties, the ZnO films were deposited on bare glass, PMMA/glass and ITO/glass substrates and their crystal properties and surface morphologies were analyzed. The structural properties of the ZnO films varied with the substrate conditions. The ZnO film deposited on the ITO/glass substrate showed better crystallinity and morphologies, such as a higher preferred c-axis orientation, lower FWHM value and larger particle size compared with the one deposited on the PMMA/glass substrate. The field effect mobility ($\mu$), threshold voltage ($V_T$) and $I_{on/off}$ switching ratio for the OITFT with the staggered structure were about $0.61\;cm^2/V{\cdot}s$, 5.5 V and $10^2$, whereas those of the OITFT with the inverted staggered structure were found to be $0.31\;cm^2/V{\cdot}s$, 6.8 V and 10, respectively. The improved electrical properties for the staggered OITFTs may originate from the improved crystal properties and larger particle size of the ZnO active layer.

• Korean Journal of Clinical Laboratory Science
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• v.41 no.3
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• pp.123-127
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• 2009

After a health examination, abnormal patients were classified into two groups. One needs clinical treatment immediately, while the other one needs check-up in 2~3 month after for blood tests and preventive medical study. To discover the status and importance of the follow-up study in a health program, blood test upon health examination was compared to the test from the follow-up. We examined patients of ages from 20's to 70's. Among these patients, most of them were between 40's and 50's, and in male patients the follow-up test were more freguent than female. We examined blood obtained from January 2007 to December 2008. We analyzed and compared initial and the follow up blood test. Lipid profile, liver test, thyroid function tests (TFTs), glucose fasting, and HbA1c were examined from the blood tests. We also surveyed their distribution and status. The value of the follow up blood tests was significantly decreased with the most striking differences in lipid profiles and liver test. Follow up study is able to improve life style of patients through doctor's advice in a health program. Therefore, we can conclude that the follow up blood test is also quite critical.