• Journal of the Korean Ceramic Society
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• v.26 no.1
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• pp.43-50
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• 1989

This experiment was conducted to investigate correlation between microstructure and electrical properties according to Zr/Ti mole ratio in Rhombohedral Phase PZT. Domain behavoir was investigated by the change of thermal expansion coefficient. Piezoelectric properties, the temperature dependence of dielectric constant and the change of dielectric constant before and after poling were measured. Crystal structure, the measurement of lattice parameter were carried by X-ray analysis. Domain pattern before and after poling was examined by SEM.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.125-129
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• 2004

[ $BaTi_4O_9$ ] thin film were grown on $Pt/Ti/SiO_2/Si$ substrate using rf magnetron sputter, and the microstructure and dielectric properties of the thin films were investigated. For the film grown at $350^{\circ}C$ and rapidly thermal annealed at $900^{\circ}C$, the $BaTi_5O_{11}$ Phase was formed. However, the $BaTi_4O_9$ phase was formed when the growing temperature exceeded $450^{\circ}C$ The dielectric constant of the $BaTi_4O_9$ thin film grown at $550^{\circ}C$ and rapidly thermal annealed at $900^{\circ}C$ was about 40 at low frequency range($100kHz{\sim}1MHz$) and 36 at microwave range($1{\sim}10GHz$) which is very close to that of the bulk $BaTi_4O_9$ phase. The dissipation factor was very low, about 0.005 at low frequency as well as microwave range.

• Journal of the Korean Vacuum Society
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• v.1 no.1
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• pp.190-197
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• 1992

In this study we have investigated physical and electrical properties of high temperature oxide (HTO) thin film using dichlorosilane (DCS) gas. This film had low etch rate and excellent step coverage, and its characteristics of Si-O bond were similar to those of thermal oxide. I-V curves also showed similar electrical properties to those of thermally grown oxide (SiO2) while time dependent dielectric breakdown (TDDB) results revealed 1/4 value of thermal oxide. However, defect density was measured to be much lower value than that of thermal oxide.

• 한국정보디스플레이학회:학술대회논문집
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• 2000.01a
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• pp.181-182
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• 2000

The glass compositions of $PbO-SiO_2-B_2O_3$ system and $P_2O_5-PbO-ZnO$ system for the transparent dielectric materials for front panel and $P_2O_5-ZnO-BaO$ and $SiO_2-ZnO-B_2O_3$ for the reflective dielectric materials for back panel of PDP(Plasma Display Panel) were investigated. As a transparent dielectric materials for front panel, $PbO-SiO_2-B_2O_3$ glass showed good dielectric properties, high transparency and proper thermal expansion matching to soda-lime glass substrate. And the reflective dielectric materials for back panel were prepared from parent glass of $SiO_2-ZnO-B_2O_3$ system and oxide filler. It was found that these glass-ceramics are useful materials for reflective dielectric layers, as those have a similar thermal expansion to soda-lime glass plate, high reflectance, low sintering temperature.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.2
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• pp.103-118
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• 2022

With the recent increase in demand for electronic devices, multi-layer ceramic capacitors (MLCCs) have become the most important core component. In particular, the next-generation MLCC with extremely high reliability is required for the 4^th industrial revolution and electric vehicle applications. Therefore, it is necessary to develop dielectric ceramic materials with high dielectric properties and reliability. During the decades, electrical properties of BaTiO₃ based dielectric ceramics, which have been widely used in MLCC industrial field, have been improved by microstructure and defect chemistry control. However, electrical properties of BaTiO₃ have reached their limits, and new types of dielectric materials have been widely studied. Based on these backgrounds, this report presents the recent development trends of BaTiO₃-based dielectric materials for the next-generation MLCCs, and suggests promising candidates to replace BaTiO₃ ceramics.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.6
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• pp.460-465
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• 2001

(Ba$_{0.6-x}$Sr$_{0.4}$Ca$_{x}$)TiO$_3$(x=1.10,0.15,0.20) specimens were fabricated by the solid state reaction method and then the structural and dielectric properties as a function of he composition ratio and sintering temperature were studied. As a result of the differential thermal analysis(DTA), exothermic peak was observed at around 102$0^{\circ}C$ due to the formation of the polycrystalline perovskite phase. The BSCT(50/40/10) specimen sintered at 150$0^{\circ}C$ showed the highest average grain size(18.25${\mu}{\textrm}{m}$). The Curie temperature and dielectric constant at room temperature decreased with increasing Ca content. The dielectric constant and dielectric loss of the BSCT(50/40/10) specimen, sintered at 145$0^{\circ}C$, were about 4324 and 0.972% at 1KHz, respectively.ively.

• Journal of the Korean Ceramic Society
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• v.32 no.9
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• pp.1056-1064
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• 1995

95Pb(Mg1/3Nb2/3)O3-5PbTiO3 (hereinafter designated as 95PMN-5PT) system was prepared by the columbite-precursor method with 2 mol% excess PbO to compensate the PbO loss during thermal process. The amount of CuO was 1~10 mol%, and the effects of CuO addition on the dielectric properties of this system have been investigated. From the microstructures, XRD analysis and dielectric measurements, the solubility limit of CuO in 95PMN-5PT was found to be around 3 mol%. Lattice parameter and Curie temperature were found to be decreased as the amount of CuO increased up to the solubility limit. This result confirmed that the Cu2+-ions substituted the Pb2+-ions. It was revealed that the addition of CuO on 95PMN-5PT promoted the sinterability and properties. The room temperature dielectric constant, the loss factor and the specific resistivity of the specimens processed with optimum conditions were 23000, 1%, and 8$\times$1011Ω.cm, respectively.

• Journal of Electrical Engineering and information Science
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• v.3 no.1
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• pp.68-72
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• 1998

The photomachinable glass-ceramics of Ag and CeO2 doped Li203-SiO2 (LAS)glass system was investigated as a function of UV irradiation time. After the expose and the non-exposed samples were heated, they went under crystalline phase with DTA, SEM, TEM and XRD of normal/high temperature. In this work, crystalline phases, microstructure and dielectric properties were studied under the various time of UV irradiation and heat treatment.

• Macromolecular Research
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• v.15 no.4
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• pp.357-362
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• 2007

Polyimide/carbon nanotube (CNT) composite films, for potential use in high performance microelectronics and aerospace applications, were prepared by mixing a polyisoimide (PII) solution and a CNT suspension in NMP, followed by casting, evaporation and thermal imidization. The CNTs were modified by a nitric acid treatment to improve the thermal and electrical properties, as well as to provide good dispersion of the CNTs in a polymer matrix. The formation of functional groups on the modified CNT was confirmed by Raman spectroscopy. Scanning electron microscopy revealed the modified CNTs to be well dispersed in the polyimide matrix, with a uniform diameter of ca. 50 nm. The thermal stability of the films containing the CNTs was improved due to the enhanced interfacial interaction and good dispersion between the polyimide matrix and modified CNTs. In addition, the thermal expansion coefficient of the composites films was slightly decreased, but the dielectric constants increased linearly with increasing CNT content.

• Macromolecular Research
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• v.15 no.2
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• pp.185-190
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• 2007

Poly(norbornene dimethyl dicarboxylate)s, (PNDMD)s, were prepared by addition polymerization with palladium(II) catalyst from pure exo-monomers, and their structure and properties were compared with those of poly(norbornene dicarboxylic acid dialkyl ester)s, (PNDADA)s. Both polymer series exhibited good solubility in general organic solvents and excellent thermal stability up to $330^{\circ}C$. Wide-angle X-ray scattering (WAXS) study indicated the presence of nano-scale layer-like order in amorphous PNDADAs, while PNDMDs showed random amorphous structure. The glass transition temperatures and dielectric constants of solid polymers were found to decrease as the alkyl side-chain length increases for both polymer series. However, PNDMDs showed lower glass transition temperatures and higher dielectric constants, as compared with those of PNDADAs containing the same alkyl substituents. This difference, caused by the higher side-group mobility of PNDMDs, may be closely related to the nano-scale order in amorphous PNDADAs and its absence in PNDMDs.