• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.12
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• pp.37-42
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• 1999

In this paper, some of main processes for the next generation integrated circuits, such as Cu damascene process using CMP, electron beam lithography, $SiO_2$ CVD and RIE, Ti/Cu-CVD were carried cut and then, two level Cu interconnects were accomplished. In the results of CMP unit processes, a 4,635 ${\AA}$/min of removal rate, a selectivity of Cu : $SiO_2$ of 150:1, a uniformity of 4.0% are obtained under process conditions of a head pressure of 4 PSI, table and head speed of 25rpm, a oscillation distance of 40 mm, and a slurry flow rate of 40 ml/min. Also 0.18 ${\mu}m\;SiO_2$ via-line patterns are fabricated using 1000 ${\mu}C/cm^2$ dose, 6 minute and 30 second development time and 1 minute and 30 second etching time. And finally sub-0.2 ${\mu}$ twolevel metal interconnects using the developed processes were fabricated and the problems of multilevel interconnects are discussed.

• Korean journal of applied entomology
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• v.49 no.3
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• pp.205-210
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• 2010

The bean bug, Riptortus pedestris (=clavatus) Fabricius (Hemiptera: Alydidae) is a serious pest of soybean in many countries. It enters a reproductive diapause in the winter by short day length (<13.5 h.) in Korea and Japan. The combined effects of temperatures ($25^{\circ}C$ and $8^{\circ}C$) and day lengths (10L:14D and 14L:10D) upon the termination of the male's diapause were studied. The combinations are (1) HTLD = $25^{\circ}C$, 14L:10D treatment for 1, 2, 3 weeks and 30 days; (2) HTSD = $25^{\circ}C$, 10L:14D treatment for 1, 2, and 3 weeks; (3) LTLD$\rightarrow$HTLD = $8^{\circ}C$, 14L:10D treatment for 1, 2, and 3 weeks followed by HTLD treatment; (4) LTSD$\rightarrow$HTLD = $8^{\circ}C$, 10L:14D treatment for 1, 2, and 3 weeks followed by HTLD. The amount of aggregation pheromone components secreted was adopted as the criteria for diapause termination in males. Males did not secrete aggregation pheromone under HTSD conditions. However, the males treated with HTLD for more than 21 days secreted significantly higher amounts of aggregation components, (E)-2-hexenyl (Z)-3-hexenoate and (E)-2-hexenyl (E)-2-hexenoate, compared to the control or HTSD treatments. The three components of the aggregation pheromone were secreted by the 14%, 29%, and 100% males treated with HTLD for 7 days, respectively. However more than 83% of the HTLD-treated males secreted all three components by the $30^{th}$ day under the treatment. In comparison, the pheromone amounts secreted by the males treated with LTLD$\rightarrow$HTLD or LTSD$\rightarrow$HTLD were equal or less than those secreted by males with continuous HTLD treatment.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.375-375
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• 2009

For many large-scale applications of high-temperature superconducting materials, large critical current density($J_c$) in high applied magnetic fields are required. A number of methods have been reported to introduce artificial pinning centers(APCs) in $YBa_2Cu_3O_{7-\delta}$(YBCO) films for enhancement of their $J_c$. We report measurements of critical current in $YBa_2Cu_3O_{7-\delta}$ films deposited by PLD on $SrTiO_3$ substrates decorated with Au nanoparticles. Au nanoparticles were synthesized on STO substrates with self assembled monolayer. Microstructural analysis of the obtained YBCO films was performed by using cross-section transmission electron microscopy(TEM). Phase and textural analysis was done using X-ray diffraction. The surface morphology and surface roughness(Ra) of the layers was measured by atomic force microscopy(AFM).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.11
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• pp.935-940
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• 2009

In this research, the composites (100-x)LCP-xBNT (x = 0, 10, 20, 30, 40 vol.%) were fabricated with thermoplastic LCP(Liquid Crystal Polymer) and BNT($BaNd_2Ti_4O_{12}$) which is a high frequency dielectric material. Their dielectric properties, mechanical strength and microstructure were investigated by Impedance analyser, Instron and SEM. In order to fabricate LCP-BNT composites, LCP resin was put into the twin screw type mixer($310^{\circ}C$), melted by keeping for 10 min. After that, BNT filler was dispersed with melted LCP resin for 15 min. in the mixer. For measuring the dielectric properties and mechanical strength, Composite specimens were made by pressing composite granule (LCP-BNT) with 7 ton in the mold at $310^{\circ}C$. With increasing the BNT content (0~40 vol.%) of the composite, Its dielectric constant increased, dielectric loss and flexural strength decreased. The dielectric constant and flexural strength of composites with 20~30 vol.% of BNT filler are 4.1~6.0 and 35~55 MPa respectively. BNT/LCP composite is the potential substrate material for the high frequency application.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.128-128
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• 2013

Fabrication of heterogeneous catalysts using Atomic Layer Deposition (ALD) has recently been attracting attention of surface chemists and physicists. In this talk, I will present recent results about structures and chemical activities of various catalysts prepared by ALD, particularly focusing on Ni-based catalysts. Ni has been considered as potential catalysts for $CO_2$ reforming of methane (CRM); however, Ni often undergoes rapid decrease in catalytic activity with time, and therefore, application of Ni as catalysts for CRM has been regarded as difficult so far. Deactivation of Ni catalysts during CRM reaction is from either coke formation on Ni surface or sintering of Ni particles during reaction. Two different strategies have been used for enhancing stability of Ni-based catalysts; $TiO_2$ nanoparticles were deposited on micrometer-size Ni particles by ALD, which turned out to reduce coke formation on Ni surfaces. Ni nanoparticles deposited by ALD on mesoporous silica showed high activity and long-term stability from CRM without coke deposition and sintering during CRM reaction. Ni-based catalysts have been also used for oxidation of toluene, which is one of the most notorious gases responsible for sick-building syndrome. It was shown that onset-temperature of Ni catalysts for toluene oxidation is as low as $120^{\circ}C$. At $250\circ}C$, total oxidation of toluene to $CO_2$ with a 100% conversion was found.

• Proceedings of the KIEE Conference
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• 2008.10a
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• pp.171-172
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• 2008

$(Ba_{0.57}Sr_{0.33}Ca_{0.10})TiO_3$ (BSCT) thick films doped with 0.1 mol% $MnCO_3$ and $Yb_2O_3$ ($0.1{\sim}0.7$ mol%) were fabricated by the screen printing method on the alumina substrate. And the structural and electrical properties as a function of $Yb_2O_3$ amount were investigated. The lattice constants of the BSCT thick film doped with 0.1 mol% is 0.3955 nm. The specimen doped with 0.7 mol% $Yb_2O_3$ showed dense and uniform grains with diameters of about 6.3 mm. The thickness of all BSCT thick films was approximately 60 mm. The Curie temperature of the BSCT specimen doped with 0.1 mol% $Yb_2O_3$ was $18^{\circ}C$, and the dielectric constantand dielectric loss at this temperature was 4637 and 4.2%, respectively. The BSCT specimen doped with 0.1 mol% $Yb_2O_3$ showed the maximum value of $349{\times}10^{-9}C/cm^2K$ at Curie temperature. The figure of merit $F_D$ for specific detectivity of the specimens doped with 0.1 mol% $Yb_2O_3$ showed the highest value of $10.9{\times}10^{-9}Ccm/J$.

• Transactions on Electrical and Electronic Materials
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• v.5 no.3
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• pp.109-112
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• 2004

In this study, in order to develop the low temperature sintering ceramics for ultrasonic vibrator, Pb(Sb$\_$$\frac{1}{2}$/Nb$\_$$\frac{1}{2}$/) O$_3$-Pb(Ni$\_$1/3/Nb$\_$2/3/)O$_3$-Pb(Zr$\_$0.48/Ti$\_$0.52/)O$_3$ ceramics were manufactured as a function of the amount of CuO addition, and their dielectric and piezoelectric characteristics were investigated. With increasing CuO addition, the grain size and density increased up to 0.3 wt% CuO addition. Taking into consideration electromechanical coupling factor(k$\_$p/) of 0.53, mechanical quality factor(Q$\_$m/) of 423, dielectric constant($\varepsilon$$\_$r/) of 1,759 and piezoelectric constant(d$\_$33/) of 362pC/N, it could be concluded that 0.5 wt% CuO added composition ceramic sintered at 920$^{\circ}C$ was suitable for ultrasonic vibrator application.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.657-661
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• 2002

PZT powder was prepared by partial oxalate method using $(Zr_{0.53}Ti_{0.47})O_2$, $Pb(NO_3)_2$ and $(COOH)_2{\cdot}2H_2O$ as a precipitant. $Nb_2O_5$ additive effect on microstructure and piezoelectric properties of PZT ceramics were investigated. The coexistence of rhombohedral and tetragonal phases of PZT ceramics at the sintering temperature of $1100^{\circ}C$ was revealed from the X-ray diffraction patterns. The grain size PZT ceramics was decreased with the increase $Nb^{5+}$. and the sinterbility of PZT ceramics was decreased with the increase $Nb^{5+}$ addition. The electromechanical coupling factors $K_p$ show above 0.60 at $1100^{\circ}C$ sintering temperature by $Nb_2O_5$ addition above 0.6mol%.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.22-25
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• 2002

In this paper, we deposited MgO buffer layer on p-type (100)Si substrate in the condition of substrate temperature 400$^{\circ}C$, working gas ratio Ar:O$_2$=80:20, RF Power 50W, working pressure 10mtorr, and the thickness of the film was about 300${\AA}$. Then we deposited Ba$\sub$0.5/Sr$\sub$0.5/TiO$_3$ thin film using RF Magnetron sputtering method on the MgO/Si substrate in various RF power of 25W, 50W, 75W. The film deposited in 50W showed the best crystalline from the XRD measurement. To know the electrical properties of the film, we manufactured Al/BSTMgO(300${\AA}$)/Si/Al structure capacitor. In the result of I-V measurement, The leakage current density of the capacitor was lower than 10$\^$-7/A/$\textrm{cm}^2$ at the range of ${\pm}$150kV/cm. From C-V characteristics of the capacitor, can calculate the dielectric constant and it was 305. Finally we deposited BST thin film on bare Si substrate and (100)MgO substrate in the same deposition condition. From the comparate of the properties of these samples, we found the properties of BST thin film which deposited on MgO/Si substrate were better than on bare Si substrate and similar to on MgO substrate.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.05b
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• pp.34-38
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• 2000

Recently, the ceramics of high permittivity are applied to DRAM and FRAM. In this study, (Ba, Sr)$TiO_3$ (BST) ceramics thin films were prepared by Sol-Gel method. BST solution was made and spin-coated on Pt/$SiO_2$/Si substrate at 4000 [rpm] for 10 seconds. Coated specimens were dried at $150[^{\circ}C]$ for 5 minutes. Coating process was repeated 3 times and then sintered at $750[^{\circ}C]$ for 30 minutes. Each specimen was analyzed structure and electrical characteristics by Fractal Process. Thickness of BST ceramics thin films are about $2000{\AA}$. Dielectric constant and loss of thin films was little decreased at 1[KHz] - 1[MHz]. Dielectric constant and loss to frequency were 250 and 0.02 in BST3. The property of leakage current as the realation between the current and the voltage was that change of the leakage current was stable when the applied voltage was 0~3[V].