• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.355-356
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• 2002

The dielectric permittance and the dielectric loss factor of several lubricating oils were measured at frequencies from 100 Hz to 1.5 MHz. The measurements were carried out under atmospheric pressure as a function of temperature and under fixed temperature as a function of pressure. Temperature and pressure dependence of dielectric relaxation time were investigated. The temperature dependence of relaxation time obeyed the Vogel-Fulcher-Tammann (VFT) law. We modified the VFT equation in order to express the dielectric relaxation time as a function of temperature and pressure. Furthermore. by taking into consideration the similarity of the temperature and pressure dependence between dielectric relaxation and mechanical relaxation. the prediction of high-pressure viscosity were conducted. The predicted results were compared with the viscosity data obtained from the falling-sphere type viscometer.

• 한국재료학회지
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• 제24권4호
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• pp.207-213
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• 2014

Flexible $BaTiO_3$ films as dielectric materials for high energy density capacitors were deposited on polyethylene terephthalate (PET) substrates by r.f. magnetron sputtering. The growth behavior, microstructure and electrical properties of the flexible $BaTiO_3$ films were dependent on the sputtering pressure during sputtering. The RMS roughness and crystallite size of the $BaTiO_3$ increased with increasing sputtering pressure. All $BaTiO_3$ films had an amorphous structure, regardless of the sputtering pressures, due to the low PET substrate temperature. The composition of films showed an atomic ratio (Ba:Ti:O) of 0.9:1.1:3. The electrical properties of the $BaTiO_3$ films were affected by the microstructure and roughness. The $BaTiO_3$ films prepared at 100 mTorr exhibited a dielectric constant of ~80 at 1 kHz and a leakage current of $10^{-8}A$ at 400 kV/cm. Also, films showed polarization of $8{\mu}C/cm^2$ at 100 kV/cm and remnant polarization ($P_r$) of $2{\mu}C/cm^2$. This suggests that sputter deposited flexible $BaTiO_3$ films are a promising dielectric that can be used in high energy density capacitors owing to their high dielectric constant, low leakage current and stable preparation by sputtering.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.114-114
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• 2012

Metal-oxide-semiconductor field-effect transistors (MOSFETs)의 critical dimension (CD)가 sub 45 nm로 줄어듬에 따라 기존에 gate dielectric으로 사용하고 있는 SiO2에서 발생되는 high gate leakage current 때문에 새로운 high dielectric constant (k) 물질들이 연구되기 시작하였다. 여러 가지 high-k 물질 중에서, aluminum-oxide (Al2O3)는 높은 dielectric constant (~10)와 전자 터널링 barrier height (~2eV) 등을 가지기 때문에 많은 연구가 되고 있다. 그러나 Al2O3를 anisotropic한 patterning을 하기 위해 주로 사용되고 있는 halogen-based 플라즈마 식각 과정에서 나타나는 Al2O3와 하부 layer간의 낮은 식각 selectivity 뿐만 아니라 표면에 발생되는 defect, stoichiometry modification, roughness 변화 등의 많은 문제점들로 인하여 device performance가 감소하기 때문에 이를 해결하기 위한 많은 연구들이 진행중이다. 따라서 본 연구에서는 실리콘 기판위의 atomic layer deposition (ALD)로 증착된 Al2O3를 BCl3/Ar 중성빔을 이용하여 원자층 식각한 후 식각 특성을 분석해 보았다. Al2O3 표면을 BCl3로 absorption시킨 후 Ar 중성빔으로 desorption 시키는 과정에서 volatile한 aluminum-chlorides와 boron oxychloride가 형성되어 layer by layer로 제거됨을 관찰 할 수 있었다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.1092-1095
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• 2005

The effect of the dielectric constant (${\varepsilon}$) of bonding materials in screen-printed carbon nanotube cathode on field enhancement factor was investigated using the ANSYS software for high-efficient CNT-cathodes. The field enhancement factor increased with decreasing the dielectric constant and reaching a maximum value when the dielectric constant is 1, the value for a vacuum. This indicates that the best bonding materials for screen-printing CNT cathodes should have a low dielectric constant and this can be used as criteria for selecting bonding materials for use in CNT pastes for high-efficient CNT-cathodes

• 대한전자공학회논문지SD
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• 제37권4호
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• pp.15-24
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• 2000

고유전 커패시터의 유전완화 특성은 시간영역에서 나타나는 커패시터의 동적특성으로 이해될 수 있으며 이것은 DRAM의 재충전 시간동안 충전된 전하를 잃어버리는 가장 주된 요인으로 인식된다. 그러므로 DRAM 동작에 미치는 영향을 고려하기 위하여 고유전 커패시터의 유전완화에 대한 등가회로를 만드는 것이 필수적이다. 그러나 아직까지 등가회로를 만들 수 있는 일반적이고 이론적인 방법이 제시되지 않고 있다. 근 본 연구에서는 고유전 커패시터의 등가회로를 주파수 영역에서 모델링하는 새로운 방법을 개발하였다. 이 방법은 이론적인 체계를 갖춘 일반적인 방법이다. 또한, 본 연구에서는 실험과정을 통해서 이 방법의 타당성으로 확인하였고, 궁극적으로 새로운 방법으로 얻어진 등가회로를 활용하여 유전완화가 DRAM 동작에 미치는 영향을 고찰하였다.

• 한국재료학회지
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• 제29권12호
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• pp.753-756
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• 2019

Orthorhombic dysprosium manganite DyMnO₃ with single phase is synthesized using solid-state reaction technique and the crystal structure and dielectric properties as functions of temperature and frequency are investigated. Thermally activated dielectric relaxations are shown in the temperature dependence of the complex permittivity, and the respective peaks are found to be shifted to higher temperatures as the measuring frequency increases. In Arrhenius plots, activation energies of 0.32 and 0.24 eV for the high- and low-temperature relaxations are observed, respectively. Analysis of the relationship between the real and imaginary parts of the permittivity and the frequencies allows us to explain the dielectric behavior of DyMnO₃ ceramics by the universal dielectric response model. A separation of the intrinsic grain and grain boundary properties is achieved using an equivalent circuit model. The dielectric responses of this circuit are discerned by impedance spectroscopy study. The determined grain and grain boundary effects in the orthorhombic DyMnO₃ ceramics are responsible for the observed high- and low-temperature relaxations in the dielectric properties.

• 반도체디스플레이기술학회지
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• 제20권4호
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• pp.167-170
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• 2021

Integrated passive device (IPD) technology has emerged with the need for 5G. In order to integrate and miniaturize capacitors inside IPD, various studies are actively performed using high-k materials and trench structures. In this paper, an EM(Electromagnetic) simulation study was performed by applying an oxide dielectric to the capacitors having a various trench type structures. Commercially available materials HfO₂, Al₂O₃, and Ta₂O₅ are applied to non, circle, trefoil, and quatrefoil type trench structures to confirm changes in each material or structure. As a result, the bigger the capacitor area and the higher dielectric constant of the oxide dielectric, the insertion loss tended to decrease.

• 한국군사과학기술학회지
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• 제10권3호
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• pp.114-119
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• 2007

Dielectric properties of quartz glass and $Si_3N_4$ are investigated using the waveguide method from room temperature to $800^{\circ}C$. For the case of dielectric constant, $Si_3N_4$ showed similar increase with quartz glass up to $300^{\circ}C$, but less increase from $300^{\circ}C$ to $800^{\circ}C$. For the case of loss tangent, those showed gradual increase with temperature except of some temperature points. The loss tangent of $Si_3N_4$ and quartz glass increased up to 18.2% and 12.5% respectively. Through these researches, high temperature dielectric properties of silicon nitride materials are characterized.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.207-207
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• 2008

Modern industry has focused on processing that produce low- loss dielectric substrates used complex micron-sized devices using tick film technologies such as tape casting and slip casting. However, these processes have inherent disadvantages fabricating high density interconnect with embedded passives for high speed communication electronic devices. Here, we have successfully fabricated porous alumina dielectric layer infiltrated with polymer solution by using inkjet printing process. Alumina suspensions were formulated as dielectric ink that were optimized to use in inkjet process. The layer was confirmed by field emission scanning electron microscope (FE-SEM) for measuring microstructure and volume fraction. In addition, the reaction kinetics and electrical properties were characterized by FT-IR and the impedance analyzer. The volume fraction of alumina in porous dielectric alumina layer is around 70% much higher than that in the conventional process. Furthermore, after infiltration on the dielectric layer using polymer resins such as cyanate ester. Excellent Q factors of the dielectric is about 200 when confirmed by impedance analyzer without any high temperature process.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 추계학술발표대회
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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.