• Journal of the Korean Ceramic Society
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• v.25 no.2
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• pp.136-142
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• 1988

β-Al2O3, which is used for solid electrolyte membrances in sodium-sulfur batteries, was prepared by sol-gel process. Sodium-n-propoxide NaOC3H7 and aluminum-isopropoxide Al(OC3H7)3 were hydrolyzated in the solution at pH 3, pH 7, pH 9 and pH 11, respectively. The sol-gel processed samples were calcined at several temperature steps, respectively and analysed by thermal analyser(DT-TGA), infrared spectrum analyser and X-ray diffraction analyser. The gelling rate of solution at pH 7 was much higher than that of the solution at pH 3. Thermal exchanging behavior of the gels at pH 3 were similar to Na2O·Al2O3·6H2O and, above pH 7, were similar to Na2O·Al2O3·3H2O. When samples' composition ratio was 9.13 : 90.87 [NaOC3H7:Al(OC3H7)3] at pH 7, β-Al2O3 was formed at 1100℃.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.391-395
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• 2000

In this study, the temperature coefficient of resonant frequency(TC $F_{r}$), dielectric and piezoelectric properties of Pb[(S $b_{1}$2/N $b_{1}$2/)$_{0.0035}$-(M $n_{1}$3/N $b_{2}$3/)$_{0.0065}$-(Z $r_{x}$ $Ti_{1-x}$ )$_{0.90}$] $O_3$ceramics is investigated with Zr/Ti ratio. The dielectric constant and electromechanical coupling factor( $k_{p}$) showed the highest values of 1257, 0.562 respectively when the Zr/Ti ratio is 49.5/50.5. The mechanical quality factor( $Q_{m}$) is the lowest value of 713 when the Zr/Ti ratio is 49.5/50.5, and increased with the decrease of the Zr/Ti ratio. The temperature coefficient of resonant frequency(TC $F_{r}$) change abruptly at the morphotropic phase boundary(MPB), which is between the rhombohedral phase with highly negative TC $F_{r}$ of -106ppm/$^{\circ}C$ and the tetragonal phase with highly positive TC $F_{r}$ of +64pp $m^{\circ}C$ as Zr/Ti ratio changes from 50/50 to 49.5/50.5.50.5..5.50.5.5.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.9
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• pp.681-685
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• 2012

We investigated the dry etching characteristics of TiN in $TiN/Al_2O_3$ gate stack using a inductively coupled plasma system. TiN thin film is etched by BCl3/He plasma. The etching parameters are the gas mixing ratio, the RF power, the DC-bias voltages and process pressures. The highest etch rate is in $BCl_3/He$ (25%:75%) plasma. The selectivity of TiN thin film to $Al_2O_3$ is pretty similar with $BCl_3/He$ plasma. The chemical reactions of the etched TiN thin films are investigated by X-ray photoelectron spectroscopy. The intensities of the Ti 2p and the N 1s peaks are modified by $BCl_3$ plasma. Intensity and binding energy of Ti and N could be changed due to a chemical reaction on the surface of TiN thin films. Also we investigated that the non-volatile byproducts such as $TiCl_x$ formed by chemical reaction with Cl radicals on the surface of TiN thin films.

• Journal of the Korean Chemical Society
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• v.23 no.3
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• pp.161-164
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• 1979

The effect of acidity and the metal surface area of the Pd loaded zeolite catalysts; prepared from $Ca^{2+}-,\;La^{3+}-,\;NH_4^+-$exchanged Y and dealuminated HY was studied for the reaction of n-butane. The amount of strong acid site determined by the temperature programmed desorption of ammonia increased in the order NaY < CaY < LaY. Total amount of acid site decreased with increasing degree of dealumination, but the portion of strong acid site increased with increasing $SiO_2/Al_2O_3$ ratio. The effective metal surface area determined by the CO adsorption technique was large for those zeolite catalysts having strong acidity. It was found that conversion of n-butane was strongly dependent on the acidity and the effective metal surface area of the catalysts. The fact that the conversion of n-butane was proportional to the effective metal surface area suggests that the dehydrogenation by metallic component is the primary step in the reaction of n-butane.

• Solar Energy
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• v.8 no.2
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• pp.19-25
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• 1988

[ $SnO_2$ ] thin films have been deposited on the pyrex glasses and silicon wafers by CVD method. Tin oxide films had a good transmittance above 80% in the visible region and the lowest sheet resistance at $520^{\circ}C$. When the ratio of $SbCl_3$ was 2wt%. The optimum conditions were obtained at the oxidation time of 3 minutes in the case that Voc and Jsc were 0.40V and $33.5mA/cm^2$ respectively and the corresponding conversion efficiency was 6.07%.

• Korean Journal of Ecology and Environment
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• v.41 no.spc
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• pp.27-34
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• 2008

The vertical distribution and origin of particulate organic matter (POM) were investigated in Shingu reservoir on 4th July (pre-monsoon) and 7th August (post-monsoon) 2006. High turbid water (120 NTU) were found at 4.5 m water depth in postmonsoon period. The average C/N ratio of POM was about 5.70 and 6.96 in surface water and bottom water, respectively in pre-monsoon period, exhibiting the close values to its ratio in phytoplankton cell. However, the average C/N ratio was 7.10 in surface water and 12.81 in bottom water in post-monsoon period. In addition, the ${\delta}^{13}C$ values of POM in pre-monsoon period ranged from -25.1%o to -26.1%o in whole water column, but the ${\delta}^{13}C$ values of POM in post-monsoon period showed relatively wide range between -23.2%o and -27.5%o. The apparently lighter values (average -27.5%o) in near bottom water (4.5 m water depth) demonstrate that POM in high turbid water in post-monsoon period may be derived from the outside terrestrial plants through heavy rainfall during the summer monsoon period. The present study suggests that carbon and nitrogen stable isotope ratios as well as C/N ratios should be useful indexes to clarify the origin of POM.

• Journal of the Microelectronics and Packaging Society
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• v.20 no.1
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• pp.27-31
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• 2013

Copper-oxide (CuO) thin films were prepared by reactive sputtering of Cu onto Si wafers and characterized using a statistical design of experiments approach. The most significant factor in controlling the electrical resistivity and deposition rate was determined to be the $O_2$ fraction. The deposited CuO thin films were characterized in terms of their physical and chemical properties, using X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), X-ray diffraction (XRD), and 4-point resistance measurements. The deposited copper thin films were characterized by XPS and XRD analyses to consist of $Cu^{2+}$. The CuO thin films of highest resistivity exhibited superior rectifying responses with regard to n-type Si wafers, with a current ratio of $3.8{\times}10^3$. These superior responses are believed to be associated with the formation of a charge-depletion region originating from the p-type CuO and n-type Si materials.

• Proceedings of the KSME Conference
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• 2000.11b
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• pp.156-161
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• 2000

In this study, quantitative nitric oxide concentration distributions are investigated in the post-flame zone of laminar premixed $CH_4/O_2/N_2$, flames by laser-induced fluorescence (LIF). The measurements are taken in flames for different equivalence ratios varying from $0.8{\sim}1.4$, and flow rate is fixed as 5slpm. The NO A-X (0,0) vibrational band around 226 nm is excited using a XeCl excimer-pumped dye laser. Selecting an appropriate NO transition minimizes interferences from Rayleigh scattering and $O_2$ fluorescence. NO concentration is rised when equivalence ratios increase at different vertical distances form nozzle tip. In any case, the maximum NO concentration reaches the maximum in reaction zone.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.136-136
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• 2011

반도체 및 전자기기 산업에 있어서 NVM은 아주 중요한 부분을 차지하고 있다. NVM은 디스플레이 분야에 많은 기여를 하고 있는데, 측히 AMOLED에 적용이 가능하여 온도에 따라 변하는 구동 전류, 휘도, color balance에 따른 문제를 해결하는데 큰 역할을 한다. 본 연구에서는 bottom gate 구조의 nc-Si NVM 실험을 진행하였다. P-type silicon substrate (0.01~0.02 ${\Omega}-cm$) 위에 Blocking layer 층인 SiO2 (SiH4:N2O=6:30)를 12.5nm증착하였고, Charge trap layer 층인 SiNx (SiH4:NH3=6:4)를 20 nm 증착하였다. 마지막으로 Tunneling layer 층인 SiOxNy은 N2O (2.5 sccm) 플라즈마 처리를 통해 2.5 nm 증착하였다. 이러한 ONO 구조층 위에 nc-Si을 50 nm 증착후에 Source와 Drain 층을 Al 120 nm로 evaporator 이용하여 증착하였다. 제작한 샘플을 전기적 특성인 Threshold voltage, Subthreshold swing, Field effect mobility, ON/OFF current ratio, Programming & Erasing 특성, Charge retention 특성 등을 알아보았다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.228-231
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• 1999

The preparation and electrical properties of LIPON electrolyte were investigated in order to fabricate all solid state thin film battery. The LIPON thin film was deposited by r.f. sputtering of Li$_3$PO$_4$ target in O$_2$-N$_2$ mixtures. The LIPON deposited at N$_2$+10% O$_2$ ratio had a conductivity at 25 $^{\circ}C$ of 1.8${\times}$10$\^$-6/S/cm. The ion conductivity of the LIPON films decreased as the O$_2$ content of the process gas increased.