• Korean Journal of Materials Research
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• v.29 no.3
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• pp.175-182
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• 2019

This study examines paraelectric $Bi_{1.5}Zn_{1.0}Nb_{1.5}O_7$ (BZN), which has no hysteresis and high dielectric strength, for energy density capacitor applications. To increase the breakdown dielectric strength of the BZN film further, poly(vinylidene fluoride) BZN-PVDF composite film is fabricated by aerosol deposition. The volume ratio of each composition is calculated using dielectric constant of each composition, and we find that it was 12:88 vol% (BZN:PVDF). To modulate the structure and dielectric properties of the ferroelectric polymer PVDF, the composite film is heat-treated at $200^{\circ}C$ for 5 and 30 minutes following quenching. The amount of ${\alpha}-phase$ in the PVDF increases with an increasing annealing time, which in turn decreases the dielectric constant and dielectric loss. The breakdown dielectric strength of the BZN film increases by mixing PVDF. However, the breakdown field decreases with an increasing annealing time. The BZN-PVDF composite film has the energy density of $4.9J/cm^3$, which is larger than that of the pure BZN film of $3.6J/cm^3$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.1
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• pp.822-826
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• 2015

This study investigated the possible use of vibration from polyvinylidene fluoride(PVDF) film to enhance the performance of the deteriorated tunnel drainage due to physical/chemical clogging of the fine particles through a series of laboratory experiments. The test program was consisted of two different experiments, fundamental investigation and drainage model test. In the fundamental investigation, flow of clay slurry mixed with 50% water (freshwater and brine) on PVDF film with various frequencies was examined. In the model tests, slurry clogging to the woven fiber attached to drainage pipe and its reduction by vibration was investigated. Results of the experiment show that vibration from PVDF film enhances the drain performance significantly. Based upon the investigation, it gives an essential data that are needed for a potential use of hybrid drainage system with PVDF.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.420-422
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• 1995

PVDF (polyvinylidene fluoride) has at least from known crystalline structure ( ; they are referred to as the $\alpha$, $\beta$, $\gamma$ and $\alpha_p$ phase or forms II, I, III and $IV_p$). In this study, the manufactured PVDF thin films through vapor deposition method had for II ( ; the substrate temperature at 30$^{\circ}C$). The dielectric behavior of poly(vinylidene fluoride) is affected by orientation and crystal modification. The very high value of the dielectric constant for high temperature conditioned film is believed to be due to the orientation effect. The loss peak caused by molecular motion of the molecules in crystalline regions.

• Progress in Superconductivity
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• v.3 no.1
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• pp.74-77
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• 2001

We have fabricated a high-Tc superconductive transistor with polyvinylidene fluoride (PVDF) gate electrode on MgO bicrystal Josephson junction by spin-coating method. The PVDF ferroelectric film is found to be suitable fur a gate electrode of the superconductive transistor since it has not only small leakage current but also high dieletric constant at low temperature. For the application of superconducting-FET, we investigated millimeter wave properties (60 GHz band) of the Josephson junction with PVDF gate electrode.

• Journal of Sensor Science and Technology
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• v.32 no.5
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• pp.328-333
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• 2023

This study experimentally verified the etch rate of the SiO₂ sacrificial layer etching process with a single etch hole using vapor-phase hydrogen fluoride (VHF) etching. To fabricate small-sized polysilicon etch holes, both circular and triangular pattern masks were employed. Etch holes were fabricated in the polysilicon thin film on the SiO₂ sacrificial layer, and VHF etching was performed to release the polysilicon thin film. The lateral etch rate was measured for varying etch hole sizes and sacrificial layer thicknesses. Based on the measured results, we obtained an approximate equation for the etch rate as a function of the etch hole size and sacrificial layer thickness. The etch rates obtained in this study can be utilized to minimize structural damage caused by incomplete or excessive etching in sacrificial layer processes. In addition, the results of this study provide insights for optimizing sacrificial layer etching and properly designing the size and spacing of the etch holes. In the future, further research will be conducted to explore the formation of structures using chemical vapor deposition (CVD) processes to simultaneously seal etch hole and prevent adhesion owing to polysilicon film vibration.

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1190-1192
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• 1995

Poly(vinylidene fluoride)(PVDF) is one of the most studied polymers in the latest date. The interest in PVDF lies in its remarkable piezoelectric and pyroelectric properties. Also, PVDF has at least four known crystalline structures(; they are referred to as the ${\alpha},\;{\beta},\;{\gamma}\;and\;{\alpha}_p$ phase or forms II, I, III and $IV_p$). In this study, the manufactured PVDF thin film through vapor deposition method had form II(; the glass at $70^{\circ}C$). This thin film was investigated by x-ray diffraction(XRD), Fourier Transform Infrared(FT-IR) spectroscopy and Differential Thermal Analysis(DTA). XRD and FT-IR indicate crystallization forms from the glass at $70^{\circ}C$ into form II.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.10
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• pp.923-929
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• 2008

On the piezoelectric polymer, PVDF (poly vinylidene fluoride), the transparent conducting oxide (TCO) electrode material thin film was deposited by roll to roll sputtering process mentioned as a mass product-friendly process for display application. The deposition method for ITO Indium Tin Oxides) as our TCO was DC magnetron sputtering optimized for polymer substrate with the low process temperature. As a result, a high transparent and good conductive ITO/PVDF film was prepared. During the process, especially, the gas mixture ratio of Ar and Oxygen was concluded as an important factor for determining the film's physical properties. There were the optimum ranges for process conditions of mixture gas ratio for ITO/PVDF From these results, the doping mechanism between the oxygen atom and the metal element, Indium or Tin was highly influenced by oxygen partial pressure condition during the deposition process at ambient temperature, which gives the conductivity to oxide electrode, as generally accepted. With our studies, the process windows of TCO for display and other application can be expected.

• Journal of Sensor Science and Technology
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• v.11 no.4
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• pp.200-208
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• 2002

This paper represents the development of an array-type flexible tactile sensor using PVDF(polyvinylidene fluoride) film and flexible circuitry. The tactile sensor which has $8{\times}8$ taxels is made by using PVDF film and FPC(flexible printed circuit) technique. Experimental results on static and dynamic properties are obtained by applying arbitrary forces and frequencies generated by the shaker. In the static characteristics, the threshold and the linearity of the sensor are investigated. Also dynamic response of the sensor subjected to the variable frequencies is examined. The signals of a contact force to the tactile sensor are sensed and processed in the DSP system in which the signals are digitalized and filtered. Finally, the signals are integrated for taking the force profile. The processed signals of the outputs of the sensor are visualized on a personal computer, the shape and force distribution of the contacted object are obtained using two and three-dimensional image in real time. The reasonable performance for the detection of contact state is verified through the experiment.

• Electrical & Electronic Materials
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• v.10 no.10
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• pp.1029-1033
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• 1997

A prototype MFSFET using ferroelectric fluoride BaMgF$_4$as a gate insulator has been successfully fabricated with the help of 2 sheets of metal mask. The fluoride film was deposited in an ultrai-high vacuum system at a substrate temperature of below 30$0^{\circ}C$ and an in-situ post-deposition annealing was conducted for 20 seconds at $650^{\circ}C$ in the same chamber. The interface state density of the BaMgF$_4$/Si(100) interface calculated by a MFS capacitor fabricated on the same wafer was about 8$\times$10$^{10}$ /cm$^2$.eV. The I$_{D}$-V$_{G}$ characteristics of the MFSFET show a hysteresis loop due to the ferroelectric nature of the BaMgF$_4$film. It is also demonstrated that the I$_{D}$ can be controlled by the “write” plus which was applied before the measurements even at the same “read”gate voltage.ltage.

• Journal of the Microelectronics and Packaging Society
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• v.8 no.3
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• pp.63-67
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• 2001

Up to now, most studies about Pt-etching have been focused on physical sputtering mechanism with Cl-based plasma, while only a limited results are available for etching characteristics with fluorine-based plasma. In this study, etch characteristics of Pt thin film with $Cl_2$/Ar and $SF_{6}$/Ar Ar gas chemistries have been studied with ECR plasma etching system. It is confirmed that $SF_{6}$/Ar Ar plasma chemistry could make volatile etch-products through the reaction with Pt thin film. Also the improvement in etch rate, etch profile and surface roughness is obtained due to the formation of volatile platinum fluoride compounds.