• 한국전기전자재료학회논문지
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• 제22권1호
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• pp.53-60
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• 2009

$ZrTiO_4$ dielectric thin films were coated by metal-organic decomposition, and annealed by rapid thermal processing up to $900^{\circ}C$ for their crytallization. Crystallized single-phase $ZrTiO_4$ thin films were fabricated above the annealing temperature of $800^{\circ}C$, but their grains were randomly oriented without specific textured orientation. Best dielectric properties were presented by the sample annealed at $800^{\circ}C$ which had crystalline structure and flat surface. Dielectric constant of the film was maintained at 32 throughout full frequency range up to 6 GHz, and dielectric loss was varied between 0.01 and 0.04.

• 한국세라믹학회지
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• 제32권5호
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• pp.635-641
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• 1995

The effects of A-site substitution with alkaline-earth ions (Ca, Sr and Ba) on the perovskite-phase formation and dielectric properties for Pb1-xMx(Zn1/3Nb2/3)O3 (0.0 x 0.5)-based relaxors were studied. Considerable improvements in the sinterability and the extent fo perovskite formation were observed with increasing the A-site substitution (x) and sintering temperature. The maximum dielectric permittivity appeared at x=0.1 for Sr and Ba substitutiion, while the relative dielectric permittivity was almost invariant in the case of Ca ion substitution. Curie temperature decreased with increasing relative amount of Sr and Ba ions but was almost invariant in case of Ca ion substitution. With increasing the amount of x, the diffuseness parameter ($\delta$) increased but the maximum dielectric constant decreased, demonstrating an enhanced diffuse phase transition (DPT) in the presence of alkaline-earth cations.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 춘계학술대회 논문집
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• pp.29-32
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• 2005

Poly (methyl methacrylate) (PMMA) is one of the promising representive of polymer gate dielectric for its high resistivity and sutible dielectric constant. PMMA (Mw=96700) films were prepared on p-Si by spin coating method. PMMA were coated compactively and flatly as observeed by AFM. MIS(Al/PMMA/p-Si) structure was made and capacitance-voltage (C-V) and current-voltage (I-V) measurements were done with PMMA films for different thermal treatment temperature. PMMA films were showed proper dielectric constant and breakdown voltage. Above the glass transition temperature PMMA films degraded. C-V measured at various frequencies, dielectric constant increased a little. The absence of hysteresis in the C-V characteristics, which eliminate the possibility of mobile charges in the PMMA films. The observed thermal stability, smooth surfaces, dielectric constant, I-V behavior implies PMMA formed by spin coating can be used as an efficient gate dielectric layer in OTFTs.

• Tribology and Lubricants
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• 제37권6호
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• pp.203-207
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• 2021

This study presents the development of dielectric constant sensors to measure lubricant properties. The lubricant oil sensor is used to measure oil properties and machine conditions. Various condition monitoring methods are applied to diagnose machine conditions. Machine condition monitoring using oil sensors has advantage over other machine condition monitoring methods. The fault conditions can be noticed at the early stages by the detection of wear particles using oil sensors. Therefore, it provides an early warning in the failure procedure. A variety of oil sensors are applied to check the machine condition. Among all oil sensors, only one sensor can measure the tendency of several properties such as acidity and water content. A dielectric constant sensor is also used to measure various oil properties; therefore, it is very useful. The dielectric constant is the ratio of the capacitance of a capacitor using that material as a dielectric to that of a similar capacitor using vacuum as its dielectric. The dielectric constant has an effect on water content, contaminants, base oil, additive, and so forth. In this study, the dielectric constant sensor is fabricated using MEMS process. In the fabrication process, the shape, gap of the electrode array, and thickness of the insulation material are considered to improve the sensitivity of the sensor.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제51권5호
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• pp.185-190
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• 2002

Capacitor material utilized in the downsizing passive devices and dynamic random access memory(DRAM) requires the physical and electrical properties at given area such as capacitor thickness reduction, relative dielectric constant increase, low leakage current and thermal stability. Common capacitor materials, $SiO_2$, $Si_3N_4$, $SiO_2$/$Si_3N_4$,TaN and et al., used until recently have reached their physical limits in their application to several hundred angstrom scale capacitor. $Ta_2O_{5}$ is known to be a good alternative to the existing materials for the capacitor application because of its high dielectric constant (25 ~35), low leakage current and high breakdown strength. Despite the numerous investigations of $Ta_2O_{5}$ material, there have little been established the clear understanding of the annealing effect on capacitance characteristic and conduction mechanism, design and fabrication for $Ta_2O_{5}$ film capacitor. This study presents the structure-property relationship of reactive-sputtered $Ta_2O_{5}$ MIM capacitor structure processed by annealing in a vacuum. X-ray diffraction patterns skewed the existence of amorphous phase in as-deposited condition and the formation of preferentially oriented-$Ta_2O_{5}$ in 670, $700^{\circ}C$ annealing. On 670, $700^{\circ}C$ annealing under the vacuum, the leakage current decrease and the enhanced temperature-capacitance characteristic stability. and the leakage current behavior is stable irrespective of applied electric field. The results states that keeping $Ta_2O_{5}$ annealed at vacuum gives rise to improvement of electrical characteristics in the capacitor by reducing oxygen-vacancy and the broken bond between Ta and O.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 C
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• pp.1618-1620
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• 2004

The $Pb(Zr_{0.4}Ti_{0.6})O_3/Pb(Zr_{0.6}Ti_{0.4})O_3$ [PZT(4060)/(6040)] multilayered thin films were deposited by RF Sputtering method on the Pt/Ti/$SiO_2$/Si substrate. This procedure was repeated several times to form PZT(4060)/(6040) heterolayerd thin films. The effects on the structural and dielectric properties of PZT multilayered thin films were investigated. The MFM(Metal Ferroelectric Metal) type capacitors were made using the PZT(4060)/(6040) multilayered thin films deposited with optimum deposition condition. An enhanced dielectric property was observed in the PZT(4060)/(6040) multilayered thin films. The relative dielectric constant and dielectric loss at 100Hz of the PZT(4060)/(6040)-5 multilayered thin films were about 1106 and 0.016, respectively.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(2)
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• pp.76-79
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• 2000

The 3$\mu\textrm{m}$-thick PVDF (Polyvinyiidene fluoride) thin film have been prepared using physical vapor deposition with electric field, and its FT-IR specrum, dielectric property and electric conduction phenomenon have been investigated. Since the characteristic peaks ate detected at 509.45 and 1273.6〔cm〕 in the FT-IR spectrum, we are confirmed that the ${\beta}$ -phase is dominant in the PVDF thin film. In the results of dielectric properties, the PVDF thin film shows anomalous dispersion, i.e. gradual decrease of dielectric constant with increase of frequency, and also that the dielectric absorption point changes from 200Hz to 7000Hz with increasing temperature of thin film, which is consistent with the Debye's theory. The activation energy (ΔH) obtained from temperature dependence of dielectric loss is 21.64 ㎉/㏖. We confirm that the electric conduction mechanism of PVDF thin film is dominated by ionic conduction by investigating the dependence of the leakage current of the thin film on the temperature and the electric field.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2003년도 춘계종합학술대회
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• pp.696-699
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• 2003

본 연구에서는 MDFM (Metal-Dielectric-ferroelectric-Metal) 구조의 강유전체 캐패시터와 수정된 Sawyer-Tower 회로를 접목시켜 강유전체의 이력곡선을 정밀하게 계산하기 위한 모델을 제시하였다. 본 모델은 스위칭 쌍극자 분극의 수학적 표현을 수치적분 알고리즘에 적용하였으며, 강유전체와 하부전극사이에 dielectric 층을 포함시켜 피로특성을 고려할 수 있다. 본 모델의 예측치를 PLT(10) 강유전체 박막의 측정결과와 비교하여 본 모델의 유효성을 입증하였다.

• 한국전기전자재료학회논문지
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• 제11권3호
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• pp.208-213
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• 1998

Microwave dielectric properties of $BiNbO_4$ containing CuO and $V_2O_5$(BN ceramics). BN ceramic with 0.07wt% $V_2O_5$ and 0.03wt% CuO (BNC3V7) was sintered at $900^{\circ}C$ where it is possible for these to be co-fired with Ag electrode. The dielectric constant of 44.3, TCF (Temperature Coefficient of resonance Frequency) of 2 ppm/$^{\circ}$ and Q${\times}f_o$ value (product of Quality value and resonance Frequency) of 22,000GHz could be obtained from those ceramics. It is observed that orthorhombic structure was stable $1000^{\circ}C$. As sintering temperature increases, the dielectric properties decreased. The main reasons were abnormal grain growth and the main peak of triclinic moved from the main peak of orthorhombic.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.2
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• pp.822-825
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• 2003

Maxwell displacement current (MDC) measurement has been employed to study the dielectric property of Langmuir-films. A method for determining the dielectric relaxation time $\tau$ of floating monolayers on water surface is presented. WC flowing across monolayers is analyzed using a rod-like molecular model. It is revealed that the dielectric relaxation time $\tau$ of monolayers in the isotropic polar orientational phase is determined using a liner relationship between the monolayer compression speed ${\alpha}$ and the molecular area Am. Compression speed ${\alpha}$ was about 30, 40, 50mm/min.