• 한국결정성장학회지
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• 제20권1호
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• pp.21-24
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• 2010

고주파 유전체 세라믹 $(Ca_{0.7}Sr_{0.3})_m(Ti_yZr_{1-y})O_3$ 의 미세구조 및 전기적 특성에 대한 Ti 이온 및 몰비의 영향을 조사하였다. $CaZrO_3$의 Zr 위치에 Ti 이온의 치환은 세라믹 소체의 소결밀도 및 미세구조에 큰 영향을 미친다. Zr 위치에 Ti 이온의 치환량 증가에 따라, 소결밀도는 급격히 증가하고, 몰비 m=1.01에서 치밀한 미세조직이 얻어졌다. 한편, 몰비 m=0.99 조성에 대해서는 Ti 치환량이 증가하여도 소결밀도 및 미세구조는 거의 변화가 없이 일정하였다. Ti 치환량 증가에 따라 TCC (temperature coeITicient of capacitance) 곡선은 시계방향으로 회전하여 몰비 m=0.99, 1.01 조성에 대해 COG 특성을 만족하였다. $CaZrO_3$의 TCC 및 소결특성 제어를 위해서는 Ti 치환량이 몰비보다는 효과적임을 보여준다.

• 한국재료학회지
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• 제19권11호
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• pp.576-580
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• 2009

$BaTiO_3$/epoxy composites have been widely investigated as promising materials for embedded capacitors in printed circuit boards. It is generally known that the dielectric constant (K) of the $BaTiO_3$/epoxy composites increases with improvement of the dispersion of $BaTiO_3$ particles in the epoxy matrix that comes from adding surfactant. The influences of surfactant addition on the dielectric properties of the $BaTiO_3$/epoxy composites are reported in the present study. The dielectric constant of the $BaTiO_3$/epoxy composites is not significantly affected by the surfactant addition. However, the temperature coefficient of capacitance increases and the peel strength decreases as the amount of added surfactant increases. The influences of surfactant addition on the dielectric properties of the neat epoxy are also very similar to those of the $BaTiO_3$/epoxy composites. The residual surfactant in the $BaTiO_3$/epoxy composites affects the temperature coefficient of capacitance and the peel strength of the epoxy matrix, which in turn affects the temperature coefficient of capacitance and the peel strength of the $BaTiO_3$/epoxy composites.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1988년도 추계학술대회 논문집
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• pp.8-11
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• 1988

(1-x-y)Pb($Zn_{1/3}Nb_{2/3})0_3-BaTiO_3PbTiO_3(0.05{\leq}x{\leq}0.20, 0.05{\leq}y{\leq}0.15$) ternary compound ceramics were fabricated by the mixed oxide method. The dielectric properties with temperature and frequency of the specimens were investigated. Relative dielectric constants of the specimens were increased with $BaTiO_3$ contents. Increasing the $BaTiO_3$contents, the variation in the relative dielectric constant with frequency, the temperature coefficient of capacitance (TCC) and the dielectric loss were decreased.

• 한국세라믹학회지
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• 제48권4호
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• pp.323-327
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• 2011

The effects of $Dy_2O_3$ and $Er_2O_3$ co-doping on electrical properties and temperature stability of barium titanate ($BaTiO_3$) ceramics were investigated in terms of microstructure and structural analysis. The dielectric constant and the insulation resistance (IR) of 0.7 mol% $Dy_2O_3$ and 0.3 mol% $Er_2O_3$ co-doped dielectrics had about 60% and 20% higher than the values of undoped one, respectively, and the temperature coefficient of capacitance (TCC) met the X7R specification. The addition of $Dy_2O_3$ contributed to electrical properties caused by increase of tetragonality; however, preferential diffusion of $Dy^{3+}$ ions toward A site in $BaTiO_3$ grain exhibited an adverse effect on temperature stability by grain growth. On the other hand, The $Er_2O_3$ addition in $BaTiO_3$ could affect the TCC behavior and the IR with suppression of grain growth caused by reinforcement of grain boundary and electrical compensation. Therefore, the enhanced electrical properties and temperature stability through the co-doping could be deduced from the increase of tetragonality and the suppression of grain growth.

• 한국결정성장학회지
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• 제19권2호
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• pp.102-105
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• 2009

$BaTiO_3$ 입자 크기가 MLCCs의 절연 특성 및 MLCCs 특성 열화에 미치는 영향을 알아보기 위해 서로 다른 입자를 사용하여 제작한 MLCCs의 가속열화시험을 $150^{\circ}C$, 75 V조건에서 실시하였다. 실험에 사용된 MLCCs는 각각 $0.525{\mu}m$, $0.555{\mu}m$, $0.580{\mu}m$의 입자 크기를 가지는 $BaTiO_3$와 Ni계 전극을 사용하여 상용화된 공정을 통해 제조되었다. 제조된 MLCCs에 대해 정상 유무 확인을 위해 X5R조건 하에서 TCC(Temperature Coefficient of Capacitance) 측정을 통해 유전 변화율에 대해 알아보았다. 세 가지 입자 크기에 따른 절연저항의 거동을 알아보기 위해 BDV(Breakdown Voltage)를 실시하였고, 가속열화시험 후 입자의 크기에 따른 MLCCs 열화의 정도와 원인을 알아보기 위해 XPS(If-ray photoelectron spectroscopy)를 통해 고장분석을 하였다. $BaTiO_3$의 입자 크기가 작을수록 절연파괴저항 및 절연저항 열화에 우수한 특성을 나타내었고, XPS 분석 결과 확인된 NiO peak과 $BaTiO_3$ peak 감소를 통해 MLCCs 열화원인이 유전체의 산소 환원과 환원된 산소와 전극간 반응임을 알 수 있었다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 II
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• pp.1061-1064
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• 2003

In this paper, we deposited A1$_2$O$_3$ thin film using atomic layer deposition(ALD) method on Ti and fabricated metal-insulator-metal(MIM) capacitor. In the result of this study, the typical deposition rate was about 1.12$\AA$/cycle. About 30 nm of Ti was consumed during deposition and TiO$_{x}$ was formed at the interface of A1$_2$O$_3$ and Ti. Its surface roughness was 1.54nm. The leakage current density was 1.5 nA/$\textrm{cm}^2$. The temperature coefficient of capacitance(TCC) of MIM capacitor was 41 ppm/$^{\circ}C$ at 1MHz and 100 ppm/$^{\circ}C$ at 100 kHz.z.

• 한국전기전자재료학회논문지
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• 제29권7호
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• pp.404-407
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• 2016

In this study, to develop low temperature sintering capacitor composition ceramics with the good dielectric properties, $(Ba_{0.86}Ca_{0.14})(Ti_{0.85}Zr_{0.12}Sn_{0.03})O_3$ (BCTZ) ceramics were prepared by the conventional solid-state reaction method. The effects of $B_2O_3$ addition on the dielectric properties and microstructure was investigated. The XRD patterns demonstrated that all the specimens showed Perovskite phase, and secondary phases are indicated in the measurement range of XRD. And also, temperature coefficient of capacitance(TCC) of all the specimen sintered at $1,180^{\circ}C$ showed +3~-56% except for x=0.006. For all the specimens, observed one peak was tetragonal cubic difuse phase transition temperature(Tc), which is located in the vicinity of room temperature.

• 한국전기전자재료학회논문지
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• 제21권7호
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• pp.645-651
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• 2008

To reduce noise in high frequency and distortion of signal, the composition of $(Ca_{0.7}Sr_{0.3})(Zr_{0.97}Ti_{0.03})O_3$ and $(Ba_{0.2}Ca_{0.4}Sr_{0.4})TiO_3$ was developed. The composition was not solid solution, but mixtures of various phases composed of Ca, Sr, Zr, Ti and Ba oxides. The dielectric constant increased, the quality factor and the insulation resistance decreased with $(Ba_{0.2}Ca_{0.4}Sr_{0.4})TiO_3$ content. The composition of $0.4(Ba_{0.2}Ca_{0.4}Sr_{0.4})TiO_3$ satisfied the electric characteristics and the temperature coefficient of dielectric constant (TCC). In addition, the glass frit and $MnO_2$ also affected the electric characteristics. From the result of the best fit simulation, $MnO_2$ 0.3 mol%, the glass frit 0.6 wt% showed the insulation resistance $906{\Omega}{\cdot}F$, the quality factor 821, and the dielectric constant 92. With the selected composition, MLCC capacitors sized $4.5{\times}3.2{\times}2.5mm$ were manufactured with 105 layered of the dielectric thickness $16{\mu}m$ using Ni inner electrode, They represented the capacitance $98{\sim}102$ nF, the quality factor 1,200 and the insulation resistance $1,500{\Omega}{\cdot}F$. Also, they had high break-down voltage with $107{\sim}115V/{\mu}m$, and satisfied the SL TCC characteristics.

• 한국세라믹학회지
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• 제46권2호
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• pp.131-136
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• 2009

Radio frequency (RF) plasma treatment is studied for the size reduction and the spheroidization of coarse particles to change them into nano-sized powders of spherical shape in MLCC fields. The uni-nanoadditives manufactured by RF plasma processing for high dispersion have been investigated for the effect on core-shell structure in dielectrics of MLCC. Microstructures have been characterized using scanning electron microscope (SEM), transmission electron microscope (TEM) and Electron Probe Micro Analyzer (EPMA). We compared the distribution of core-shell grains between specimens manufactured using uni-nanoadditive and using mixed additive. In addition, the uniformity of rare earth elements in the core-shell structured grains was analyzed. It was shown, from TEM observations, that the sintered specimen manufactured using uni-nanoadditives had more dense small grains with well-developed core-shell structure than the specimen using mixed additives, which had a homogeneous microstructure without abnormal grain growth and shows broad temperature coefficient of capacitance (TCC) curves in all temperature ranges because of well dispersed additives.

• 한국전기전자재료학회논문지
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• 제23권3호
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• pp.216-221
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• 2010

Employing statistical design of experiments, the difference in doping behaviors of rare-earth ions and their effects on the dielectric property and microstructure of $BaTiO_3$-MgO-$MnO_2$-($Ba_{0.4}Ca_{0.6}$) $SiO_3-Re_2O_3$ (Re = $Y_2O_3$, $Er_2O_3$) system were investigated. Through the statistical analysis we have found that the amount of $Re_2O_3$ are significantly affecting on the dielectric properties. The $Re_2O_3$ improved the dielectric constant, dielectric loss and R*C constant, so the appropriate contents of $Y_2O_3$ and $Er_2O_3$ were 0.8 ~ 1.2 mol% and 0.8 ~ 1.3 mol%, respectively. The MLCC(mutilayer chip capacitor) with $2.0{\times}1.2{\times}1.2mm$ size and 475 nF was also suited for X7R with the above composition. It showed that the dielectric constant and RC constant were 2,839 and 3,675 ${\Omega}F$, respectively in the sintering condition at $1250^{\circ}C$ in $Po_2$ $10^{-7}$ Mpa.