• Journal of the Korean Vacuum Society
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• v.18 no.1
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• pp.24-29
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• 2009

The SiOC film as inter layer insulator was researched the reason of the decreasing the dielectric constant by the ionic polarization and electronic polarization, respectively. The dielectric constant was measured using the conventional C-V measurement system, and the reflective index owing to the electronic polarization. Two kinds of dielectric constants were compared and then induced the origin of low-k materials. The chemical properties of the SiOC film were analyzed by the FTIR spectra, and the carbon content was obtained by the deconvoluted data of FTIR spectra. The variation of the carbon content tended to similar to the trend of reflective index, but was in inverse proportion to the dielectric constant. The effect of the electronic polarization did not affect the decreasing the dielectric constant, however the ionic polarization decreased effectively the dielectric constant of the SiOC film.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.10a
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• pp.20.2-20.2
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• 2011

BMNO dielectric materials with a pyrochlore structure have been chosen and they have quite high dielectric constants about 210 for the bulk material. In the case of thin films, 200-nm-thick BMNO films deposited at room temperature showed a low leakage current density of about $10^{-8}\;A/cm^2$ at 3 V and a dielectric constant of about 45 at 100 kHz. Because high dielectric constant BMNO thin films kept an amorphous phase at a high temperature above $900^{\circ}C$. High dielectric constant BMNO thin films grown at room temperature have many applications for flexible electronic devices. However, because the dielectric constant of the BMNO films deposited at room temperature is still low, percolative BMNO films (i.e., those were grown in a pure argon atmosphere) sandwiched between ultra-thin BMNO films grown in an oxygen and argon mixture have greater dielectric constants than standard BMNO films. However, they still showed a leakage problem at a high voltage application. Accordingly, a new nano-structure that uses BMNO was required to construct the films with a dielectric constant higher than that of its bulk material. The fundamental reason that the BMNO-Bi nano-composite films grown by RF-Sputtering deposition had a dielectric constant higher than that of the bulk material was addressed in the present study. Also we used the graphene as bottom electrode instead of the Cu bottom electrode. At first, we got the high leakage current density value relatively. but through this experiment, we could get improved leakage current density value.

• Journal of the Korean Ceramic Society
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• v.29 no.7
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• pp.572-576
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• 1992

Dielectric constant of ferroelectric ceramics with poling is important in relation to the mechanism of dielectric breakdown. From the research about the dielectric constant variation with poling in tetragonal and rhombohedral phase PZT ceramics, it is known that the dielectric constant after poling is determined by competing effects between increasing effects (compressive stress induced by electrostriction of piezoelectric effects) and decreasing increase in large grain size with poling is smaller than in small grain size.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.289-292
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• 2003

Laboratory tests were performed to investigate the dielectric property of saturated sands contaminated by heavy metals solution at low frequency. Differences of contamination and the real part of dielectric constant depend on heavy metal concentration was measured at low frequency, 100KHz below. The optimal frequency to develop the detection potentials of monitoring was 1KHz, 10KHz, 100KHz. At this frequency, Heavy metal contamination of saturated sands contamination can be recommended by analysis of complex dielectric constant.

• Journal of the Korean Vacuum Society
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• v.17 no.4
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• pp.341-345
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• 2008

The SiOC film of carbon centered system was prepared using bistrimethylsilylmethane and oxygen mixed precursor by the chemical vapor deposition. The chemical properties of the SiOC film were analyzed by the contact anlge and FTIR spectra. The dielectric constant of the deposited films decreased after annealing process, and the correlation between the increasing the BTMSM/$O_2$ flow rate ratio and the dielectric constant did not exist. However, the trend of increasing or decreasing of the dielectric constant repeated and there is the correlation ship between the dielectric constant and the Si-O-C bond in the range of $950{\sim}1200\;cm^{-1}$. The dielectric constant decreased between samples with the chemical shift. The lowest dielectric constant was 1.65 at the sample, which was observed the chemical shift.

• Tribology and Lubricants
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• v.37 no.2
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• pp.41-47
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• 2021

An experimental device was developed for analysis of hydraulic oil characteristics with dielectric constant sensors. Online analysis is the most effective method of the three methods used for analyzing lubricant oils. This is because it can monitor the machine condition effectively using oil sensors in real time without requiring excellent analysis skill and eliminates human errors. Determining the oil quality usually requires complex laboratory equipment for measuring factors such as density, viscosity, base number, acid number, water content, additive, and wear debris. However, the electric constant is another indicator of oil quality that can be measured on-site. The electric constant is the ratio of the capacitance of a capacitor using that material as a dielectric, compared with a similar capacitor that has a vacuum as its dielectric. The electric constant affects the factors such as the base oil, additive, temperature, electric field frequency, water content, and contaminants. In this study, the tendency of the electric constant is investigated with a variation of temperature, water content, and dust weight. The experimental device can control working temperature and mix the contaminants with oil. A machine condition monitoring program developed to analyze hydraulic oil is described. This program provides graph and digital values with variation of time. Moreover, it includes an alarm system for when the oil condition is bad.

• Proceedings of the KIEE Conference
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• 2005.11a
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• pp.36-38
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• 2005

This study is about how to lower the driving voltage that enables to move the micro droplet by the EWOD (Electro Wetting On Dielectric) mechanism. EWOD is well known that it is used ${\mu}-TAS$ digital micro fluidics system. As the device which is fabricated with dielectric layer between electrode and micro droplet is applied voltage, the hydrophobic surface is changed into the hydrophilic surface by electrical property. Therefore, EWOD induces the movement of micro droplet with reducing contact angle of micro droplet. The driving voltage was depended on the dielectric constant of dielectric layer, thus it can be reduced by increase of dielectric constant. Typically, very high voltage ($100V{\sim}$) is used to move the micro droplet. In previous study, we used $Ta_{2}O_{5}$ as the dielectric layer and driving voltage was 23V that reduced 24 percent compared with $SiO_2$. In this study, we used $BZN(Bi_{2}O_{3}ZnO-Nb_{2}O_{5})$ layer which had high dielectric constant. It was operated the just 12V. And micro droplet was moved within Is on 15V. It was reduced the voltage until 35 percents compare with $Ta_{2}O_{5}$ and 50 percents compare with $SiO_2$. The movement of micro droplet within 1s was achieved with BZN (ferroelectrics)just on 15V.

• Transactions on Electrical and Electronic Materials
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• v.10 no.4
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• pp.116-120
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• 2009

Ceramic-polymer composites have been investigated for their suitability as embedded capacitor materials because they combine the processing ability of polymers with the desired dielectric properties of ceramics. This paper discusses the dielectric properties of the ceramic ($BaTiO_3$)-polymer (Epoxy) composition as a function of ceramic particle size at a ceramic loading of 40 vol%. The dielectric constant of these ceramic-polymer composites increases as the powder size decreases. Results show that ceramic-polymer composites have a high dielectric constant associated with the $BaTiO_3$ powder with a 200 nm particle size, high insulation resistance, high breakdown voltage (> 22 KV/mm), and low dielectric loss (0.018-0.024) at 1 MHz.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1738-1745
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• 2015

Radiation characteristics of a probe-fed rectangular microstrip patch antenna printed on a finite grounded high permittivity substrate are investigated systematically for various square grounded dielectric substrate sizes with several thicknesses and dielectric constants by experiment and full wave simulation. The effect of the substrate size on the radiation characteristics of a rectangular patch antenna is mainly determined by the effective dielectric constant of surface waves on a grounded dielectric substrate. As the effective dielectric constant of surface waves increases, the substrate sizes for the maximum broadside gain and the required onset for a large magnitude of squint angle decrease, while the variations of the broadside gain, the front-to-back ratio, and the magnitude of squint angle versus the substrate size increase due to the increase of the power of the surface wave.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.989-992
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• 2001

(Ba$\sub$0.6-x/Sr$\sub$0.4/Ca$\sub$x/)TiO$_3$(x=0.10, 0.15, 0.20) specimens were fabricated by the solid state reaction method and then the structural and dielectric properties as a function of the composition ratio and sintering temperature were studied. The BSCT(50/40/10) specimen sintered at 1500$^{\circ}C$ showed the highest average grain size(18.25 ${\mu}$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 1450$^{\circ}C$, were about 4324 and 0.972% at 1KHz, respectively. Dielectric constant at room temperature decreased with increasing an applied field, tunability of the BSCT(50/40/10) sintered at 1300$^{\circ}C$ was 18%.