• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2012년도 추계학술대회
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• pp.586-589
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• 2012

In this paper, a tunable capacitor like an interdigital one is presented for low-voltage applications. In order to reduce operation voltage by enhancing fringing electric fields, two finger-patterned electrodes are vertically separated by employing a multi-layer thin film dielectric of a para-/ferro-/para-electrics without spacing between electrodes. The proposed tunable capacitor was fabricated on a quartz wafer and its characteristics are analyzed in terms of effective capacitance and tunability with a function of applied voltages, compared to the conventional interdigital capacitor (IDC). At 8V and 2 GHz, the proposed tunable capacitor shows the tunability of 18 % that is 10.3 % higher than that of the compared one.

• 반도체디스플레이기술학회지
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• 제9권3호
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• pp.75-78
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• 2010

In this study we investigated the electrical properties of ZnO-based MOS capacitor with $HfO_2$ as the gate dielectric. MIM capacitor, which uses either $HfO_2$ or $Al_2O_3$ as the dielectric layer, is also studied to understand the dependency of the dielectrics on the preparation conditions. It was found that thinner $HfO_2$ films yield better electrical properties, namely lower leakage current and higher breakdown electric field. These properties were observed to deteriorate when subsequently annealed. Capacitance in the depletion region of MOS capacitor was found to increase with UV ozone treatment time up to 60min. However, when the treatment time was extended to 120min, the trend is reversed. The 'threshold voltage' was also observed to positively shift with UV ozone treatment time up to 60min. The shift apparently saturated for longer treatment.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 추계학술발표대회
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• pp.25.2-25.2
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• 2011

Recently, thin film capacitors used for vehicle inverters are small size, high capacitance, fast response, and large capacitance. But its applications were made up of liquid as electrolyte, so its capacitors are limited to low operating temperature range and the polarity. This research proposes using Ni-P alloys by electroless plating as the electrode instead of liquid electrode. Our substrate has a high aspect ratio and complicated shape because of anodic aluminum oxide (AAO). We used AAO because film thickness and effective surface area are depended on for high capacitance. As the metal electrode instead of electrolyte is injected into AAO, the film capacitor has advantages high voltage, wide operating temperature, and excellent frequency property. However, thin film capacitor made by electroless-plated Ni on AAO for full-filling into etched tunnel was limited from optimizing the deposition process so as to prevent open-through pore structures at the electroless plating owing to complicated morphological structure. In this paper, the electroless plating parameters are controlled by temperature in electroless Ni plating for reducing reaction rate. The Electrical properties with I-V and capacitance density were measured. By using nickel electrode, the capacitance density for the etched and Ni electroless plated films was 100 nFcm-2 while that for a film without any etch tunnel was 12.5 nFcm-2. Breakdown voltage and leakage current are improved, as the properties of metal deposition by electroless plating. The synthesized final nanostructures were characterized by scanning electron microscopy (SEM).

• 한국재료학회지
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• 제24권5호
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• pp.259-265
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• 2014

$ZrO_2$ films were coated on aluminum etching foil by the sol-gel method to apply $ZrO_2$ as a dielectric material in an aluminum(Al) electrolytic capacitor. $ZrO_2$ films annealed above $450^{\circ}C$ appeared to have a tetragonal structure. The withdrawal speed during dip-coating, and the annealing temperature, influenced crack-growth in the films. The $ZrO_2$ films annealed at $500^{\circ}C$ exhibited a dielectric constant of 33 at 1 kHz. Also, uniform $ZrO_2$ tunnels formed in Al etch-pits $1{\mu}m$ in diameter. However, $ZrO_2$ film of 100-200 nm thickness showed the withstanding voltage of 15 V, which was unsuitable for a high-voltage capacitor. In order to improve the withstanding voltage, $ZrO_2$-coated Al etching foils were anodized at 300 V. After being anodized, the $Al_2O_3$ film grew in the directions of both the Al-metal matrix and the $ZrO_2$ film, and the $ZrO_2$-coated Al foil showed a withstanding voltage of 300 V. However, the capacitance of the $ZrO_2$-coated Al foil exhibited only a small increase because the thickness of the $Al_2O_3$ film was 4-5 times thicker than that of $ZrO_2$ film.

• 한국항행학회논문지
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• 제16권6호
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• pp.1038-1043
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• 2012

본 연구에서는 재구성 RF 회로 설계 응용을 위해 BZN/BST/BZN 다층 유전체를 이용한 고-가변 커패시터를 설계 및 그 특성을 측정하였다. 고-가변 특성의 BST계 강유전체와 저-손실 특성의 BZN계 상유전체를 이용하여 47%의 가변성과 0.005의 $tan{\delta}$ 값을 갖는 저-손실 고-가변 BZN/BST/BZN 다층 유전체를 제작하였다. 이 다층 유전체를 이용하여 quartz 기판 위에 $327{\times}642{\mu}m2$ 크기로 제작된 가변 커패시터 칩은 15 V의 인가전압과 800 MHz 주파수에서 Q-factor가 10이고 60 %의 가변율을 달성하였다.

• 센서학회지
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• 제16권2호
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• pp.97-103
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• 2007

Crystallized carbon nitride film that has many stable physical and/or chemical properties has been expected potentially by a new electrical material. However, one of the most significant problems degrading the quality of carbon nitride films is an existence of N-H and C-H bonds from the deposition environment. The possibility of these reactions with hydroxyl group in carbon nitride films, caused by a hydrogen attack, was suggested and proved in our previous reports that this undesired effect could be applied for fabricating micro-humidity sensors. In this study, MIS capacitor and MIM capacitor with $5{\mu}m{\times}5{\mu}m$ meshes were fabricated. As an insulator, carbon nitride film was deposited on a $Si_{3}N_{4}/SiO_{2}/Si$ substrate using reactive magnetron sputtering system, and its dielectric constant, C-V characteristics and humidity sensing properties were investigated. The fabricated humidity sensors showed a linearity in the humidity range of 0 %RH to 80 %RH. These results reveal that MIS and MIM $CN_{X}$ capacitive humidity sensors can be used for Si based micro-humidity sensors.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.197-197
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• 2008

There are fast growing demands for new dielectric materials for passive capacitors of RF-ICs and other wireless applications. One of the bulk microwave dielectric materials which have superior properties is $ZrTiO_4$ due to its large dielectric constant and high quality factor. Therefore, $ZrTiO_4$ is worth studying as a form of thin film to be applied for passive capacitors of integrated circuits. In this study, we fabricated metal-insulator-metal type capacitors with $ZrTiO_4$ dielectric thin film, and evaluated their capacitor properties.

• 한국전기전자재료학회논문지
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• 제11권8호
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• pp.596-600
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• 1998

A method for the nondestructive read-out of the memory in ferroelectric thin films is demonstrated using the detection second harmonic currents introduced in the ferrolelectric capacitor as a response to an ac signal. The sign and phase of the second harmonic current depends on the polarized state +$P_r or -P_r$, The studied ferroelectric PZT thin film is found to have desirable features for the use as a memory element. This method and material seems as a promising approach for the nonvolatile memory storage.

• 반도체디스플레이기술학회지
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• 제19권4호
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• pp.84-87
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• 2020

The properties of ultra-thin two-dimensional (2D) organic ferroelectric Langmuir-Blodgett (LB) films of the poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] were investigated to find possible applicability in flexible and wearable electronics applications. In the C-V characteristics of the MFM capacitor of 2-monolayer of 5 nm films, a butterfly hysteresis curve due to the ferroelectricity of P(VDF-TrFE) was confirmed. Typical residual polarization value was measured at 2μC/㎠. When the MFM capacitor with ultra-thin ferroelectric film was measured by applying a 10 Hz bipolar pulse, it was shown that 65% of the initial polarization value in 105 cycles deteriorated the polarization. The leakage current density of the 2-monolayer film was maintained at about 5 × 10-8 A/㎠ for the case at a 5MV/cm electric field. The resistivity of the 2-monolayer film in the case at an electric field at 5 MV/cm was more than 2.35 × 1013 Ω·cm.

• Transactions on Electrical and Electronic Materials
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• 제10권4호
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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.