• International Journal of Internet, Broadcasting and Communication
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• v.6 no.1
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• pp.13-15
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• 2014

We develop a method to fabricate a flexible thin film audio systems using polyvinylidene fluoride(PVDF). The system we designed showed the properties of increased flexibility, transparency, and sound pressure levels. As an input port of two terminals, transparent oxide thin film with a low resistivity is adopted. In order to provide dielectric insulation, a transparent insulating oxide thin film is coated to obtain double-layered structure. In the range of visible light, the output from the output of the system showed a increased and improved sound pressure level. The piezoelectric polymer film of PVDF is used to produce mechanical vibration due to the applied electrical voltage signal. An analog electric voltage signal is transformed into sound waves in the audio system.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.479-479
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• 2011

Flexible inverters based on complementary thin-film transistor (CTFTs) are important because they have low power consumption and other advantages over single type TFT inverters. In addition, integrated CTFTs in flexible electronic circuits on low-cost, large area and mechanically flexible substrates have potentials in various applications such as radio-frequency identification tags (RFIDs), sensors, and backplanes for flexible displays. In this work, we introduce flexible complementary inverters using pentacene and amorphous indium gallium zinc oxide (IGZO) for the p-channel and n-channel, respectively. The CTFTs were fabricated on polyimide (PI) substrate. Firstly, a thin poly-4-vinyl phenol (PVP) layer was spin coated on PI substrate to make a smooth surface with rms surface roughness of 0.3 nm, which was required to grow high quality IGZO layers. Then, Ni gate electrode was deposited on the PVP layer by e-beam evaporator. 400-nm-thick PVP and 20-nm-thick ALD Al2O3 dielectric was deposited in sequence as a double gate dielectric layer for high flexibility and low leakage current. Then, IGZO and pentacene semiconductor layers were deposited by rf sputter and thermal evaporator, respectively, using shadow masks. Finally, Al and Au source/drain electrodes of 70 nm were respectively deposited on each semiconductor layer using shadow masks by thermal evaporator. Basic electrical characteristics of individual transistors and the whole CTFTs were measured by a semiconductor parameter analyzer (HP4145B, Agilent Technologies) at room temperature in the dark. Performance of those devices then was measured under static and dynamic mechanical deformation. Effects of cyclic bending were also examined. The voltage transfer characteristics (Vout- Vin) and voltage gain (-dVout/dVin) of flexible inverter circuit were analyzed and the effects of mechanical bending will be discussed in detail.

• Proceedings of the KIEE Conference
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• 2001.11a
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• pp.168-170
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• 2001

The NiCr is an important material for present thin-film resistor application owing to its low TCR and thermal stability. In this work, the NiCr thin films were deposited on corning glass substrate by reactive magnetron sputtering and the annealing at temperatures range from 300 to $500^{\circ}C$ for 20 min in vacuum. X-ray, AFM, $R_s$(surface leakage current) have been used to study the structural and electrical properties of the NiCr thin films. The high precision NiCr thin films resistor with TCR(temperature coefficient of resistance) of less then 10 ppm/$^{\circ}C$ was obtained under in in-situ annealing at $300^{\circ}C$ on Cr buffer layer substrate. It is clear that the NiCr thin-films resistor electrical properties are low TCR related with it's annealing and buffer layer condition. NiCr thin film resistor having a good thermal stability and low TCR properties are expected for the application to the dielectric material of passive component.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.81-84
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• 2004

The NiCr is an important material for present thin-film resistor application owing to its low TCR and thermal stability. In this work, the NiCr thin films were deposited on coming glass substrate by reactive magnetron sputtering and the annealing at temperatures range from 300 to $500^{\circ}C$ for 20 min in vacuum. X-ray, AFM, $R_s$(surface leakage current) have been used to study the structural and electrical properties of the NiCr thin films. The high precision NiCr thin films resistor with TCR(temperature coefficient of resistance) of less then $10\;ppm/^{\circ}C$ was obtained under in in-situ annealing at $300^{\circ}C$ on Cr buffer layer substrate. It is clear that the NiCr thin-films resistor electrical properties are low TCR related with it's annealing and buffer layer condition. NiCr thin film resistor having a good thermal stability and low TCR properties are expected for the application to the dielectric material of passive component.

• Journal of the Korean Vacuum Society
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• v.8 no.2
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• pp.93-101
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• 1999

The purposed of this paper is to investigate the electrical and thermal stability of Polyvinylidene fluoride(PVDF) organic thin films prepared by the vapor deposition method. The differential scanning calorimetry curve of the PVDF organic thin films prepared by increasing substrate temperature showed that the melting curve increased from $128^{\circ}C$ to $142^{\circ}C$. This result implied that the PVDF organic thin film prepared by increasing substrate temperature increased intermolecular force in the crystalline region. The anomalous properties in dielectric constant and dielectric loss at low frequency and high temperature were described for PVDF organic thin film containing impurity carriers. It was confirmed that in view of electric conductive characteristics the ohm's law is satisfied in the range of lower electric field and ln J was proportional to the electric field ln E as like the conventional property of ionic conduction in the range of higher electric field. It was confirmed that major carrier of conductivity was ions. The electrical stability was improved according to an increase of the substrate temperature. On the basis of this experimental result, it could be observed that the optimum temperature of substrate for the electrical and thermal stability was at $105^{\circ}C$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.7
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• pp.567-571
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• 2001

We investigated the structural and electrical properties of Ba(Zr$_{x}$Ti$_{1-x}$ )O$_3$(BZT) thin films with a mole fraction of x=0.2 and a thickness of 150 nm. BZT films were prepared on Pt/SiO$_2$/Si substrate with the various substrate temperature by a RF magnetron sputtering system. When the substrate temperature was above 50$0^{\circ}C$, we obtained multi-crystalline BZT films oriented to (110), (111), and (200) directions. As the substrate temperature increases, the films are crystallized and their dielectric constants become high. C-V characteristic curve of the film deposited at high temperature is more sensitive than that of the film deposited at low temperature. The parameters of the BZT film are as follows; the dielectric constants(dissipation factors) at 1 MHz are 95(0.021), 140(0.024), and 240(0.033) deposited at 400, 500, $600^{\circ}C$, respectively; the leakage currents at 666.7 kV/cm are 5.73, 23.5, and 72.8x10$^{-8}$ A/$\textrm{cm}^2$ fo the films deposited at 400, 500, and 600 $^{\circ}C$, respectively; the leakage currents at 666.7kV/cm are 5.73, 23.5, and 72.8x10$^{-8}$ A/$\textrm{cm}^2$ for the films deposited at 400, 500, $600^{\circ}C$, respectively. The BZT film deposited at 40$0^{\circ}C$ shows stable electrical properties, but dielectric constant for application is a little small.ll.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.1046-1048
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• 2004

Performances of organic thin film transistors (OTFTs) can be detrimentally affected by the state of the gate dielectric. Because of the bad stability of polymers, OTFTs with polymer gate dielectrics often provide abnormal characteristics. In this study, we report the condensation effect of the polymer gate dielectric layer. For the observations of the effect of the condensation, the spin-coated polymer layers with various deposition conditions were fabricated and left under low vacuum condition for several days. It is observed that the thickness of polymer layer and the electrical characteristic of OTFTs vary with the condensation time.

• Journal of the Korean Vacuum Society
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• v.7 no.3
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• pp.167-272
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• 1998

The fluorine doped silicon oxide (SiOF) intermetal dielectric (IMD) films havc been of interest due to their lower dielectric constant and compatibility with existing process tools. However, instability issues related to hond and increasing dielectric constant due to water absorption when the SiOF film was exposured to atmospheric ambient. Therefore, the purpose nf this research is to study the effect of post oxygen plasma treatment on the resistance of nioisture absorption and reliability of SiOF film. Improvement of moisture ahsorption resistance of SiOF film is due to the forming of thin $SiO_2$ layer at the SiOF film surface. It is thought that the main effect of the improvement of moisture absorption resistance was densification of the top layer and reduction in the numher of Si-F honds that tend to associate with OH honds. However, the dielectric constant was inucased when plasma treatment time is above 5 min. In this study, therefore, it is thought that the proper plasma treatment time is 3 min when plasma treatment condition is 700 W of microwave power, 3 mTorr of process pressure and $300^{\circ}C$ of substrate temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.395-395
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• 2007

We report on the fabrication of soluble pentacene-based thin-film transistors (TFTs) that consist of $NiO_x$, poly-vinyl phenol (PVP), and Ni for the source-drain (SID) electrodes, gate dielectric, and gate electrode, respectively. The $NiO_x$ SID electrodes of which the work function is well matched to that of soluble pentacene are deposited on a soluble pentacenechannel by sputter deposited of NiO powder and show a moderately low but still effective transmittance of ~65% in the visible range along with a good sheet resistance of ${\sim}40{\Omega}/{\square}$. The maximum saturation current of our soluble pentacene-based TFT is about $15{\mu}A$ at a gate bias of -40showing a high field effect mobility of $0.06cm^2/Vs$ in the dark, and the on/off current ratio of our TFT is about $10^4$. It is concluded that jointly adopting $NiO_x$ for the S/D electrodes and PVP for gate dielectric realizes a high-quality soluble pentacene-based TFT.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.71-71
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• 2012

As the critical dimensions of integrated circuits are scaled down, the line width and spacing between the metal interconnects are made smaller. The dielectric film used as insulation between the metal lines contributes to the resistance-capacitance (RC) time constant that governs the device speed. If the RC time delay, cross talk and lowering the power dissipation are to be reduced, the intermetal dielectric (IMD) films should have a low dielectric constant. The introduction of Cu and low-k dielectrics has incrementally improved the situation as compared to the conventional $Al/SiO_2$ technology by reducing both the resistivity and the capacitance between interconnects. Some of the potential candidate materials to be used as an ILD are organic and inorganic precursors such as hydrogensilsequioxane (HSQ), silsesquioxane (SSQ), methylsilsisequioxane (MSQ) and carbon doped silicon oxide (SiOCH), It has been shown that organic functional groups can dramatically decrease dielectric constant by increasing the free volume of films. Recently, various inorganic precursors have been used to prepare the SiOCH films. The k value of the material depends on the number of $CH_3$ groups built into the structure since they lower both polarity and density of the material by steric hindrance, which the replacement of Si-O bonds with Si-$CH_3$ (methyl group) bonds causes bulk porosity due to the formation of nano-sized voids within the silicon oxide matrix. In this talk, we will be introduce some properties of SiOC(-H) thin films deposited with the dimethyldimethoxysilane (DMDMS: $C_4H_{12}O_2Si$) and oxygen as precursors by using plasma-enhanced chemical vapor deposition with and without ultraviolet (UV) irradiation.