• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.302.1-302.1
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• 2016

Solution-processed amorphous metal-oxide thin-film transistors (TFTs) are considered as promising candidates for the upcoming transparent and flexible electronics due to their transparent property, good performance uniformity and possibility to fabricate at a low-temperature. In addition, solution processing metal oxide TFTs may allow non-vacuum fabrication of flexible electronic which can be more utilizable for easy and low-cost fabrication. Recently, for high-mobility oxide TFTs, multi-layered oxide channel devices have been introduced such as superlattice channel structure and heterojunction structure. However, only a few studies have been mentioned on the bias illumination stress in the multi- layered oxide TFTs. Therefore, in this research, we investigated the effects of bias illumination stress in solution-processed bilayer oxide TFTs which are fabricated by the deep ultraviolet photochemical activation process. For studying the electrical and stability characteristics, we implemented positive bias stress (PBS) and negative bias illumination stress (NBIS). Also, we studied the electrical properties such as field-effect mobility, threshold voltage ($V_T$) and subthreshold slop (SS) to understand effects of the bilayer channel structure.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.421.1-421.1
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• 2016

We studied indium-doped zinc oxide (IZO) film grown by atomic layer deposition (ALD) as transparent conductive oxide (TCO). A variety of TCO layer, such as ZnO:Al (AZO), InSnO2(ITO), Zn (O,S) etc, has been grown by various method, such as ALD, chemical vapor deposition (CVD), sputtering, laser ablation, sol-gel technique, etc. Among many deposition methods, ALD has various advantages such as uniformity of film thickness, film composition, conformality, and low temperature deposition, as compared with other techniques. In this study, we deposited indium-doped zinc oxide thin films using diethyl[bis(trimethylsilyl)amido]indium [Et2InN(TMS)2] as indium precursor, DEZn as zinc precursor and H2O as oxidant for ALD and investigated the optical and electrical properties of IZO films. As an alternative, this liquid In precursor would has several advantages in indium oxide thin-film processes by ALD, especially for low resistance indium oxide thin film and high deposition rate as compared to InCp, InCl3, TMIn precursors etc. We found out that Indium oxide films grown by Et2InN(TMS)2 and H2O precursor show ALD growth mode and ALD growth window. We also found out the different growth rate of Indium oxide as the substrate and investigated the effect of the substrate on Indium oxide growth.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.182.1-182.1
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• 2015

Transparent conducting oxides (TCOs)는 높은 투과율과 낮은 전기전도도를 갖고 있어 광다이오드, 태양전지 등 광소자에 적용하기 위해 많은 연구가 진행되어 왔다. 특히 Indium oxide 계열의 박막은 TCO 물질 중 하나로서 3.6 eV 의 wide bandgap을 가지고 있고, 높은 투과율과 낮은 전기 전도도 (< $10-3{\Omega}cm$)를 보여 다양한 응용이 가능해 오랫동안 연구 되어 지고 있다. 게다가 Indium oxide 계열의 박막은 낮은 가격과 화학적 안정성, 공정과정의 편의성 등 다양한 이점을 가지고 있어서 현재는 더 낮은 가격으로 생성해 더 높은 효율을 만드는데 관심이 집중되고 있다. 이러한 박막은 태양광 흡수층에서 생성되는 캐리어의 이동 및 외부 전극과의 접촉에서 발생하는 손실을 줄이기 위한 전극용 소재로 연구되어지고 있다. 본 연구에서는 Indium Molybdenum Oxide 박막을 Indium oxide와 Molybdenum 타겟을 이용하여 co-sputtering 방법으로 증착하였다. Indium molybdenum oxide 박막은 일정한 Mo 도핑농도와 일정한 Ar 개스 분압에서 다양한 기판온도 변화를 통해 증착하였다. 제작된 Indium molybdenum oxide 박막은 Hall Effect Measurement, Ultraviolet-Visible spectroscopy 및 X-Ray Diffraction (XRD) 등을 분석해 기판의 온도변화에 따른 전기비저항 및 광 투과도의 특성변화를 조사하였다.

• Journal of Life Science
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• v.12 no.4
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• pp.423-426
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• 2002

Enantioselective resolution of racemic para-nitrostyrene oxide was investigated using epoxide hydrolase activity of Aspergillus niger LK for the production of optically pure (S)-para-nitrostyrene oxide. To overcome the poor solubility of the substrate, enantioselective hydrolysis in an organic solvent was attempted under optimized reaction conditions including reaction temperature and water content. (S)-para-Nitrostyrene oxide with high optical purity (> 99% ee) was obtained at 37% yield using fungal epoxide hydrolase-catalyzed enantioselective resolution.

• Biomolecules & Therapeutics
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• v.7 no.4
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• pp.315-321
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• 1999

Since it has been known that hypoxia increases inducible nitric oxide synthase (iNOS) gene expression through hypoxia responsive element, it was possible to establish the hypothesis that nitric oxide could be a mediator of hypoxia to inhibit Cyplal promoter activity. In order to test this hypothesis, we have undertaken the study to examine the effects of hypoxia and nitric oxide on Cyplal promoter activity in Hepa I cells. Mouse Cyplal 5'flanking DNA, 1.6 Kb was cloned into pGL3 expression vector in order to construct pmCyplal-Luc. Hepa I cells were transfected with pmCyplal-Luc and were treated with $10^{-9}$ M TCDD and nitric oxide producing agents, such as lipopolysaccharide(LPS), sodium nitroprusside (SNP). Luciferase activity of reporter gene was measured from pmCyplal-Luc transfected Hepa I cell lysate which contains 2 g total protein using luciferin as a substrate. Nitric oxide producing agents, such as lipopolysaccharide (LPS), sodium nitroprusside(SNP) showed inhibition of luciferase activity that was induced by $10^{-9}$M TCDD treatment with dose dependent manner. Concomitant treatment of 1mM $N^G$-nitro-ι-arginine with $10^{-6}$~$10^{-4}$M sodium nitro-prusside recovered luciferase activity from the TCDD induced luciferase activity that was inhibited by nitric oxide producing agents. These demonstrated that nitric oxide could be a mediator of inhibitors on dioxin induced Cyplal expression in Hepa I cells.

• Korean Journal of Pharmacognosy
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• v.35 no.4 s.139
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• pp.283-287
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• 2004

The effect of water extract from Cnidii Rhizoma (CRW) on proliferation of human breast cancer cells, nitric oxide production, nitric oxide synthase expression, and ornithine decarboxylase activity was tested. CRW inhibited the growth of both estrogen-dependent MCF-7 and estrogen-independent MDA-MB-23I human breast cancer cells. Lipopolysaccharide-induced nitric oxide (NO) production was significantly reduced by CRW at the concentration of 0.5, 1.0 and 5.0 mg/ml. Expression of inducible nitric oxide synthase (iNOS) was also suppressed with the treatment of CRW in Raw 264.7 cells. CRW inhibited induction of ornithine decarboxylase by 12-0-tetradecanoylphorbol-13-acetate, a key enzyme of polyamine biosynthesis, which is enhanced in tumour promotion. Therefore, CRW is worth further investigation with respect to breast cancer chemoprevention or therapy.

• Electrical & Electronic Materials
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• v.9 no.5
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• pp.476-482
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• 1996

The multi-dielectric layer SiO$_{2}$/Si$_{3}$N$_{4}$/SiO$_{2}$(ONO) is used to improve electrical capacitance and to scale down the memory device. In this paper, improvement of the capacitance by reducing the bottom oxide thickness in the nitride deposition with load lock(L/L) vacuum system is studied. Bottom oxide thickness under the nitride layer is measured by ellipsometer both in L/L and non-L/L systems. Both results are in the range of 3-10.angs. and 10-15.angs., respectively, independent of the nitride and top oxide thickness. Effective thickness and cell capacitance for SONOS capacitor are in the range of 50-52.angs. and 35-37fF respectively in the case of nitride 70.angs. in L/L vacuum system. Compared with non-L/L system, the bottom oxide thickness in the case of L/L system decreases while cell capacitance increases about 4 fF. The results obtained in this study are also applicable to ONO scaling in the thin bottom oxide region of memory stacked capacitor.

• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.723-725
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• 1998

STI CMP process are substituting gradually for LOCOS(Local Oxidation of Silicon) process to be available below sub-0.5um technology and to get planarized. The other hand, STI CMP process(especially STI CMP with RIE etch back process) has some kinds of defect like Nitride residue, Torn Oxide defect, etc. In this paper, we studied how to reduce Torn Oxide defects after STI CMP with RIE etch back process. Although Torn Oxide defects which occur on Oxide on Trench area is not deep and not sever, Torn oxide defects on Moat area is sometimes very deep and makes the yield loss. We did test on pattern wafers witch go through Trench process, APCVD process, and RIE etch back process by using an REC 472 polisher, IC1000/SUV A4 PAD and KOH base slurry to reduce the number of torn defects and to study what is the root causes of torn oxide defects.

• Korean Journal of Materials Research
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• v.22 no.1
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• pp.1-7
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• 2012

Thin film electrode consisting purely of porous anodic tin oxide with well-defined nano-channeled structure was fabricated for the first time and its electrochemical properties were investigated for application to an anode in a rechargeable lithium battery. To prepare the thin film electrode, first, a bi-layer of porous anodic tin oxides with well-defined nano-channels and discrete nano-channels with lots of lateral micro-cracks was prepared by pulsed and continuous anodization processes, respectively. Subsequent to the Cu coating on the layer, well-defined nano-channeled tin oxide was mechanically separated from the specimen, leading to an electrode comprised of porous tin oxide and a Cu current collector. The porous tin oxide nearly maintained its initial nano-structured character in spite of there being a series of fabrication steps. The resulting tin oxide film electrode reacted reversibly with lithium as an anode in a rechargeable lithium battery. Moreover, the tin oxide showed far more enhanced cycling stability than that of powders obtained from anodic tin oxides, strongly indicating that this thin film electrode is mechanically more stable against cycling-induced internal stress. In spite of the enhanced cycling stability, however, the reduction in the initial irreversible capacity and additional improvement of cycling stability are still needed to allow for practical use.

• Corrosion Science and Technology
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• v.14 no.6
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• pp.301-312
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• 2015

Corrosion of zirconium fuel cladding is known to limit the lifetime and reloading cycles of fuel in nuclear reactors. Oxide layers formed on ZIRLO4^{TM}$ cladding samples, after immersion for 300-hour and 50-day in a simulated primary water chemistry condition ($360^{\circ}C$ and 20 MPa), were analyzed by using the scanning transmission electron microscopy (STEM), in-situ transmission electron microscopy (in-situ TEM) with the focused ion beam (FIB) technique, and X-ray diffraction (XRD). Both samples (immersion for 300 hours and 50 days) revealed the presence of the ZrO sub-oxide phase at the metal/oxide interface and columnar grains developed perpendicularly to the metal/oxide interface. Voids and micro-cracks were also detected near the water/oxide interface, while relatively large lateral cracks were found just above the less advanced metal/oxide interface. Equiaxed grains were mainly observed near the water/oxide interface.