• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제37회 하계학술대회 초록집
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• pp.50-50
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• 2009

• 한국세라믹학회지
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• 제29권9호
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• pp.695-704
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• 1992

In (Pb, La)(Zr, Ti)O3 ceramic system, the functionally gradient material (FGM) was developed, and its processing and properties were investigated. The FGMs were successfully prepared through doctor blade method with acrylic binder system as well as mold stacking press method. The ultrasonic treatment was very effective for particle dispersion in slurry, and it lead to form clack-free green films. The strain-voltage characteristics of the FGM system was significantly improved which fabricated between a high piezoelectric-low dielectric and a low piezoelectric-high dielectric composition layer.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
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• pp.131-134
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• 2003

[ $ZnWO_4$ ] shows excellent frequency selectivity due to its high quality factor($Q{\times}f$) at microwave frequencies. However, in order to use $ZnWO_4$ as multilayered wireless communication components, its other properties such as sintering temperature($1050^{\circ}C$), ${\tau}_f$ ($-70ppm/^{\circ}C$) and ${\varepsilon}_r(15.5)$ should be modified. In present study, $TiO_2$ and LiF were used to improve the microwave dielectric and sintering properties of $ZnWO_4$. $TiO_2$ additions to $ZnWO_4$ changed ${\tau}_f$ from negative to positive value, and also increased ${\varepsilon}_r$ due to its high ${\tau}_f$ ($+400ppm/^{\circ}C$) and ${\varepsilon}_r$(100). At 20 mol% $TiO_2$ addition, ${\tau}_f$ was controlled to near zero $ppm/^{\circ}C$ with ${\varepsilon}_r=19.4$ and $Q{\times}f=50000GHz$. However, the sintering temperature was still high to $1100^{\circ}C$. LiF addition to the $ZnWO_4+TiO_2$ mixture was greatly reduced the sintering temperature from $1100^{\circ}C$ to $850^{\circ}C$ due to liquid phase formation. Also LiF addition decreased the ${\tau}_f$ value due to its high negative ${\tau}_f$ value. Therefore, by controlling the $TiO_2$ and LiF amount, temperature stable LTCC material in the $ZnWO_4$-TiO_2-LiF$ system could be fabricated.

• Transactions on Electrical and Electronic Materials
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• 제3권3호
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• pp.25-28
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• 2002

In this study, microstructural, dielectric and electrical properties of (Pb$\sub$0.83/) (La$\sub$0.2/Ce$\sub$0.8/)$\sub$0.08/TiO$_3$(PCT) ceramics as a function of MnO$_2$ addition and electrode size variation were investigated for 30 MHz high frequency ceramic resonator application. Grain size was gradually increased according to the increase of MnO$_2$ addition amount. Moreover, the density showed a constant value with increasing MnO$_2$ addition amount. Dielectric constant was decreased with increasing MnO$_2$ addition amount. Curie temperature of all the composition ceramics was nearly constant around 330$^{\circ}C$. The maximum D.R.of 50.5 dB and maximum Q$\sub$mt3/ of 1842 in the 3$\^$rd/ overtone vibration mode were appeared at the composition of 0.3wt% MnO$_2$, respectively.

• 한국재료학회지
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• 제34권6호
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• pp.283-290
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• 2024

The aggressive scaling of dynamic random-access memory capacitors has increased the need to maintain high capacitance despite the limited physical thickness of electrodes and dielectrics. This makes it essential to use high-k dielectric materials. TiO₂ has a large dielectric constant, ranging from 30~75 in the anatase phase to 90~170 in rutile phase. However, it has significant leakage current due to low energy barriers for electron conduction, which is a critical drawback. Suppressing the leakage current while scaling to achieve an equivalent oxide thickness (EOT) below 0.5 nm is necessary to control the influence of interlayers on capacitor performance. For this, Pt and Ru, with their high work function, can be used instead of a conventional TiN substrate to increase the Schottky barrier height. Additionally, forming rutile-TiO₂ on RuO₂ with excellent lattice compatibility by epitaxial growth can minimize leakage current. Furthermore, plasma-enhanced atomic layer deposition (PEALD) can be used to deposit a uniform thin film with high density and low defects at low temperatures, to reduce the impact of interfacial reactions on electrical properties at high temperatures. In this study, TiO₂ was deposited using PEALD, using substrates of Pt and Ru treated with rapid thermal annealing at 500 and 600 ℃, to compare structural, chemical, and electrical characteristics with reference to a TiN substrate. As a result, leakage current was suppressed to around 10^-6 A/cm² at 1 V, and an EOT at the 0.5 nm level was achieved.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1995년도 추계학술대회 논문집
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• pp.14-17
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• 1995

In this study, fur the use of portable communication multilayer devices. 0.15wt% V$_2$O$\_$5/ added BiNbO$_4$which is low-fire microwave dielectric ceramic as able to co-fire with high conductors was made into specimens with the additions of Cr$_2$O$_3$0.04, 0.2, 0.4, 0.8, 1.2wt%. These specimens were sintered at 930, 960. 990, 1030$^{\circ}C$ respectively to make the microwave dielectric resonators. These resonators were investigated by measuring the structure and dielectric properties. The density of the specimens was increased by the amounts of the Cr$_2$O$_3$and increased by increasing the temperature. 0.8wt% Cr$_2$O$_3$added and sintered at 960$^{\circ}C$ specimen skewed 49 dielectric constant. Q$.$f values were increased by the amounts of Cr$_2$O$_3$. And Q value was deteriorated by the additions of Cr$_2$O$_3$at sufficiently sintered temperatures. Negative resonant temperature coefficients were moved to positive by the amounts of Cr$_2$O$_3$and returned negative again at 1.2wt%. Temperature characteristics were deteriorated at 1030$^{\circ}C$.

• 전자공학회논문지A
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• 제30A권5호
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• pp.30-35
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• 1993

We have investigated microwave dielectric properties of TiO$_{2}$ added (Pb$_{1-x}$Ca$_{x}$)ZrO$_{3}$ Ceramics with x=0.33, 0.35, and 0.37 sintered at 1400$^{\circ}C$ for 2 h. For additions of up to 3wt% of TiO$_{2}$ in (Pb$_{0.63}$ Ca$_{0.37}$)ZrO$_{3}$ (x=0.37), TiO$_{2}$ was completely soluble in (Pb, Ca)ZrO3 phase and did not affect the grain size of ceramics. Dielectric constant and temperature coefficient of resonant frequency increased due to the formation of solid solution, whereas Q value decreased linearly as TiO$_{2}$ increased up to 1 wt%. However, the dielectric loss was very high as TiO$_{2}$ exceeded 2 wt%. It was also shown that as Ca ion content in 0.5 wt% TiO$_{2}$ added (Pb$_{1-x}$,Ca$_{x}$)ZrO$_{3}$ decreased from x=0.37 to x=0.33, dielectric constant increased and Q value decreased.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 C
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• pp.1417-1419
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• 1997

In this paper, the dielectric properties is made researches by the dose of electron beam in order to investigate the electrical properties for transformer oils due to electron beam irradiation. To measure the dielectric loss of irradiated specimen, the liquid electrode of coaxial cylindrical shape is used, and its geometric capacitance is 16 [pF]. And the dielectric dissipation factor, $tan{\delta}$, is measured by using the Video Bridge 2150. The thermal static oven with an automatic temperature controller is used so as to apply specific temperature to specimen. This experiments for measuring the dielectric loss is performed at $20{\sim}120[^{\circ}C]$ in temperature range, $30{\sim}1.5{\times}10^5[Hz]$ in frequency and $300{\sim}500[mV]$ in voltage.

• Bulletin of the Korean Chemical Society
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• 제34권1호
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• pp.99-106
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• 2013

Polyaniline-yttrium trioxide (PAni-$Y_2O_3$) composites were synthesized by the in-situ polymerization of aniline in the presence of $Y_2O_3$ The composite formation and structural changes in these composites were investigated by X-ray diffraction (XRD), Fourier transform infra red spectroscopy (FTIR), scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). The direct current (DC) electrical conductivity of the order of $0.51{\times}10^{-2}\;S\;cm^{-1}-0.283\;S\;cm^{-1}$ in the temperature range 300 K-473 K indicates semiconducting behavior of the composites. Room temperature AC conductivity and dielectric response of the composites were studied in the frequency range of 10 Hz to 1 MHz. The variation of AC conductivity with frequency obeyed the power law, which decreased with increasing weight percentage (wt %) of $Y_2O_3$. Studies on dielectric properties shows the relaxation contribution coupled by electrode polarization effect. The dielectric constant and dielectric loss in these composites depend on the content of $Y_2O_3$ with a percolation threshold at 20 wt % of $Y_2O_3$ in PAni. Electromagnetic interference shielding effectiveness (EMI SE) of the composites in the frequency range 100 Hz to 2 GHz was in the practically useful range of -12.2 dB to -17.2 dB. The observed electrical and shielding properties were attributed to the interaction of $Y_2O_3$ particles with the PAni molecular chains.

• E2M - 전기 전자와 첨단 소재
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• 제10권7호
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• pp.674-681
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• 1997

Ternary compound ceramics, (1-y-x) BaTiO$_3$-y SrTiO$_3$-x MgTiO$_3$(0.00 x 0.20), were fabricated by the conventional ceramic process. The structural and dielectric properties of specimens were investigated while varying the composition and sintering temperature(1,200~1,45$0^{\circ}C$) in order to obtain the optimum condition of capacitor. As is well known, Curie temperature(T$_{c}$) of high dielectric-based ceramic(BaTiO$_3$) was shifted and temperature of capacitance was decreased in according to increase of solid solution with (Sr, Mg)TiO$_3$. As a result, a suitable condition of compound rate for capacitor was obtained such as the BSM-11(0.8BaTiO$_3$-0.1SrTiO$_3$-0.1MgTiO$_3$), and sintering temperature was sintered at 1,25$0^{\circ}C$ for two hours. In this case, dielectric constant<1,300, dielectric loss(tan$\delta$)<0.03, and the variation rate of capacitance had less than 3% in the range -10~7$0^{\circ}C$.>.