• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.3
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• pp.233-237
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• 2002

A giga-bit DRAM(dynamic random access memory) technology with W/WNx/poly-Si dual gate electrode is presented in 7his papers. We fabricated $0.16\mu\textrm{m}$ CMOS using this technology and succeeded in suppressing short-channel effects. The saturation current of nMOS and surface-channel pMOS(SC-pMOS) with a $0.16\mu\textrm{m}$ gate was observed 330 $\mu\A/\mu\textrm{m}$ and 100 $\mu\A/\mu\textrm{m}$ respectively. The lower salutation current of SC-pMOS is due to the p-doped poly gate depletion. SC-pMOS shows good DIBL(dram-induced harrier lowering) and sub-threshold characteristics, and there was no boron penetration.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.8
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• pp.17-24
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• 2004

Quantum effects in the poly-gate are analyzed in two dimensions using the density-gradient method, and their impact on the short-channel effect of double-gate MOSFETs is investigated. The 2-D effects of quantum mechanical depletion at the gate to sidewall oxide is identified as the cause of large charge-dipole formation at the corner of the gate. The bias dependence of the charge dipole shows that the magnitude of the dipole peak-value increases in the subthreshold region and there is a large difference in carrier and potential distribution compared to the classical solution. Using evanescent-nude analysis, it is found that the quantum effect in the poly-gate substantially increases the short-channel effect and it is more significant than the quantum effect in the Si film. The penetration of potential contours into the poly-gate due to the dipole formation at the drain side of the gate corner is identified as the reason for the substantial increase in short-channel effects.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.26-29
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• 1999

The I-V characteristics of the n-channel offset gated poly-Si TETs have been systematically investigated in order to analyse the effects of offset region. The on currents are reduced due to the series resistance by the offset length and there is no kink phenomenon in offset devices. The off currents of the offset gated TFTs are remarkably reduced to 10$^{-12}$ A independent of gate and drain voltage because the electric field is weakened by the increase of the depletion region width near the drain region. It is shown that the offset regions behave as a series resistance and reduce lateral and vertical electric field.

• JSTS:Journal of Semiconductor Technology and Science
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• v.7 no.4
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• pp.287-298
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• 2007

A two-dimensional treatment of the potential distribution under the depletion approximation is presented for poly-crystalline silicon thin film transistors. Green's function approach is adopted to solve the two-dimensional Poisson's equation. The solution for the potential distribution is derived using Neumann's boundary condition at the silicon-silicon di-oxide interface. The developed model gives insight into device behavior due to the effects of traps and grain-boundaries. Also short-channel effects and drain induced barrier lowering effects are incorporated in the model. The potential distribution and electric field variation with various device parameters is shown. An analysis of threshold voltage is also presented. The results obtained show good agreement with simulated results and numerical modeling based on the finite difference method, thus demonstrating the validity of our model.

• JSTS:Journal of Semiconductor Technology and Science
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• v.5 no.3
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• pp.159-167
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• 2005

Quantization effects (QEs), which manifests when the device dimensions are comparable to the de Brogile wavelength, are becoming common physical phenomena in the present micro-/nanometer technology era. While most novel devices take advantage of QEs to achieve fast switching speed, miniature size and extremely small power consumption, the mainstream CMOS devices (with the exception of EEPROMs) are generally suffering in performance from these effects. In this paper, an analytical model accounting for the QEs and poly-depletion effects (PDEs) at the silicon (Si)/dielectric interface describing the capacitance-voltage (C-V) and current-voltage (I-V) characteristics of MOS devices with thin oxides is developed. It is also applicable to multi-layer gate-stack structures, since a general procedure is used for calculating the quantum inversion charge density. Using this inversion charge density, device characteristics are obtained. Also solutions for C-V can be quickly obtained without computational burden of solving over a physical grid. We conclude with comparison of the results obtained with our model and those obtained by self-consistent solution of the $Schr{\ddot{o}}dinger$ and Poisson equations and simulations reported previously in the literature. A good agreement was observed between them.

• Korean Journal of Microbiology
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• v.32 no.3
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• pp.182-185
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• 1994

Effects of nitrogen and carbon sources on the decolorization rate of poly R-478 dye by a white rot basidiomycete Coriorus versicolor IFO 30388 were examined. The fungus exhibited 87.2% of decolorization rate when it was cultured in the state of stationary in a nitrogen-limited medium (pH 4.5) which contained 2.0% glucose, 0.04% ammonium tartrate, 0.02% poly R-478 dye, 2% $KH_2PO_4$, 0.5% $MgSO_4{\cdot}7H_2O$, 0.1% $CaCl_2{\cdot}2H_2O$, 0.002% thiamine-HCl and 10 mM 2,2 dimethylsuccinate (sodium) at $28^{\circ}C$ for 10 days. Decolorization of the dye occurred in the presence of nitrogen source in the medium and decolorization rate increased rapidly after depletion of $NH_4^+$ from the medium.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.28A no.9
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• pp.736-742
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• 1991

N$^{+}$poly gate NMOSFETs and p$^{+}$ poly gate (surface type) PMOSFETs with three different gate oxides(SiO2, NO, and ONO) were fabricated. The rapid thermal nitridation and reoxidation techniques have been applied to gate oxide formation. The current drivability of the ONO NMOSFET shows larger values than that of the SiO2 NMOSFET. The snap-back occurs at a lower drain voltage for SiO$_2$ cases for ONO NMOSFET. Under the maximum substrate current bias conditions, hot-carrier effects inducting threshold voltage shift and transconductance degradation were investigated. The results indicate that ONO films exhibit less degradation in terms of threshold voltage shift. It was confirmed that the ONO samples achieve good improvement of hot-carrier immunity. In a SiO$_2$ SC-PMOSFET, with significant boron penetration, it becomes a depletion type (normally-on). But ONO films show excellent impurity barrier properties to boron penetration from the gate.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.8
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• pp.3363-3368
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• 2014

Background: Curcumin, a phenolic compound extracted from the rhizomes of Curcuma longa, has shown cytotoxic effects against a variety of cancers. The aim of this study was to identify potential microRNA (miRNA) mediators of the anticancer effects of curcumin in ovarian cancer cells. Materials and Methods: SKOV3 ovarian cancer cells were treated with curcumin ($10-60{\mu}M$) and miR-9 expression, cell proliferation, and apoptosis were assessed. The effects of miR-9 depletion on curcumin-mediated growth suppression were also examined. Phosphorylation of Akt and forkhead box protein O1 (FOXO1) was measured in cells with miR-9 overexpression or curcumin treatment. Results: Curcumin caused a significant and dose-dependent increase of miR-9 expression in SKOV3 cells, while significantly impeding cell proliferation and stimulating apoptosis. Depletion of miR-9 significantly (p<0.05) attenuated the growth-suppressive effects of curcumin on SKOV3 cells, coupled with reduced percentages of apoptotic cells. In contrast, overexpression of miR-9 significantly enhanced the cleavage of caspase-3 and poly(ADP-ribose) polymerase and promoted apoptotic death in SKOV3 cells. Western blot analysis showed that both miR-9 overexpression and curcumin similarly caused a significant (p<0.05) decline in the phosphorylation of Akt and FOXO1, compared to untreated cells. Conclusions: The present study provided evidence that curcumin exerts its cytotoxic effects against SKOV3 ovarian cancer cells largely through upregulation of miR-9 and subsequent modulation of Akt/FOXO1 axis. Further studies are needed to identify direct targets of miR-9 that mediate the anticancer effects of curcumin in ovarian cancer cells.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.5
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• pp.1374-1381
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• 2004

The water extract of Dohongsamul-tang(DHSMT)has been traditionally used for treatment of ischemic heart in oriental medicine. However, little is known about the mechanism by which the water extract of DHSMT rescues cells from these damages. Therefore, this study was designed to evaluate the protective effects of DHSMT on zinc-mediated cytotoxicity in H9c2 cardiomyoblast cells. This study demonstrates that treatment of H9c2 cells with zinc caused a decrease in cell viability in a dose dependent manner and a chromatin condensation. Zinc induced the cleavage of poly(ADP-ribose) polymerase (PARP). In addition, zinc induced the decrease of Bcl-2, as well as increase of Bak expression and mitochondrial dysfunction. Zinc-induced H9c2 cell death was remarkably prevented by the pretreatment of DHSMT with consistent suppression of the cleavage of poly(ADP-ribose) polymerase (PARP), mitochondrial dysfunction and the expression of Bak and Bcl-2. Taken together, the results suggest that zinc induced severe cell death in H9c2 cardiomyoblast cells via intracellular GSH(reduced glutathione) depletion and the protective effects of DHSMT against oxidative injuries may be achieved through modulation of mitochondrial dysfunction and scavenging of ROS(reactive oxygen species).

• The Journal of Korean Medicine
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• v.26 no.2 s.62
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• pp.63-76
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• 2005

Objectives: Reactive oxygen species (ROS) have been implicated in the pathogenesis of a wide range of acute and longterm neurodegenerative diseases. This study was undertaken to examine whether Sunghyangchungisan(SHCS), a well-known prescription in Korean traditional medicine, might have beneficial effects on ROS-induced brain cell injury. Methods: Human neuroglioma cell line A172 and H2O2 were employed as an experimental model cell and oxidant. Results: SHCS effectively protected the cells against both the necrotic and apoptotic cell death induced by H2O2. The effect of SHCS was dose-dependent at concentrations ranging from 0.2 to 5mg/ml. SHCS significantly prevented depletion of cellular ATP and activation of poly (ADP-ribose) polymerase induced by H2O2. It also helped mitochondria to preserve its functional integrity estimated by MTT reduction ability. Furthermore, SHCS significantly prevented H202-induced release of cytochrome c into cytosol. Determination of intracellular ROS showed that SHCS might exert its role as a powerful scavenger of intracellular ROS. Conclusions: The present study provides clear evidence for the beneficial effect of SHCS on ROS-induced neuroglial cell injury. The action of SHCS as an ROS-scavenger might underlie the mechanism.