• Electrical & Electronic Materials
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• v.16 no.9
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• pp.62.2-62
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• 2003

Material Characteristics of zirconium oxide thin films obtained by plasma enhanced chemical vapor deposition on p-type Si(100) substrates were investigated to explain their unable electrical properties. The films obtained without heating had polycrystalline nanograins that are mostly of a tetragonal phase under oxygen-deficient plasma conditions but transformed into a monoclinic phase with increasing $O_2$ addition in the plasma. Mostly amorphous bulk $ZrO_2$ with a relatively thicker and smoother interfacial layer was obtained from oxygen-rich plasmas, resulting in a decrease in both the overall dielectric constant and the leakage current density. the interfacial layer formed between the bulk $ZrO_2$ and Si substrate was analyzed to be zirconium silicate, which approached $SiO_2$ as its zirconium content decreased with the increasing gas phase $O_2$ content.

• Journal of the Korean Ceramic Society
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• v.31 no.8
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• pp.920-926
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• 1994

Ta doped PZT thin films were prepared by a reactive sputtering method with a 3-gun magnetron co-sputter, and effects of Ta doping on physical and electrical properties of the films were studied. Within the doping range of 0 to 3.6 at%, Ta doping enhanced the crystallographic orientation of (110), but reduced that of (100). Ta doped PZT had a larger grain size of about 20 ${\mu}{\textrm}{m}$ compared with that of 5 ${\mu}{\textrm}{m}$ for un-doped PZT. Pits and holes of PZT films which used to appear with annealing at high temperature due to evaporation of PbO were much suppressed with addition of Ta. The leakage current could be reduced down to 1.27$\times$10-8 A/$\textrm{cm}^2$ and the charge storge density as large as 25.8$\mu$C/$\textrm{cm}^2$ was obtained.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.35-35
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• 2003

Recent progress in the integration of the ferroelectric random access memories (FRAM) has attracted much interest. Strontium bismuth tantalate(SBT) is one of the most attractive materials for use in nonvolatile-memory applications due to low-voltage operations, low leakage current, and its excellent fatigue-free property. High-density FRAMs operated at a low voltage below 1.5V are applicable to mobile devices operated by battery. SBT films thinner than 0.1 #m can be operated at a low voltage, because the coercive voltage (Vc) decreases as the film thickness is reduced. In addition, the thickness of the SBT film will have to be reduced so it can fit between adjacent storage nodes in a pedestal type capacitor in future FRAMs.

• Journal of Electrical Engineering and Technology
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• v.6 no.6
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• pp.836-841
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• 2011

Plasma polymerized methyl methacrylate (ppMMA) thin films were deposited by plasma polymerization technique with different plasma powers and subsequently thermally treated at temperatures of 60 to $150^{\circ}C$. To find a better ppMMA preparation technique for application to organic thin film transistor (OTFT) as dielectric layer, the chemical composition, surface morphology, and electrical properties of ppMMA were investigated. The effect of ppMMA thin-film preparation conditions on the resulting thin film properties were discussed, specifically O-H site content in the pMMA, dielectric constant, leakage current density, and hysteresis.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.963_964
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• 2009

This paper presents an output ripple reduction of Active-Clamp Forward Converter, which is mainly composed of interleaving two active-clamping forward converters. By interleaving, Output ripple is reduced. The leakage inductance of the transformer or an additional resonant inductance is employed to achieve ZVS during the dead times. The duty cycles are not limited to be equal and within 50%. The complementary switching and the resulted interleaved output inductor currents diminish the current ripple in output capacitors. Accordingly, the smaller output chokes and capacitors lower the converter volume and increase the power density. Detailed analysis of this ouput reduction of Active-Clamp Forward Converter is described.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.672-675
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• 2001

The Sr$\sub$0.8/Bi$\sub$2.4/Ta$_2$O$\sub$9/(SBT) thin films are deposited on Pt-coated electrode(Pt/TiO$_2$/SiO$_2$/Si) using RF magnetron sputtering method. With increasing annealing tempera ture from 600[$^{\circ}C$] to 850[$^{\circ}C$], Bi-layered perovskite phase was crystallized above 650[$^{\circ}C$]. The maximum remanent polarization and the coercive electric field is 11.60[${\mu}$C/$\textrm{cm}^2$], 48[kV/cm] respectively. The dielectric constant and leakage current density is 213, 1.01${\times}$10$\^$-8/ A/$\textrm{cm}^2$ respectively at annealing temperature of 750[$^{\circ}C$].

• Transactions on Electrical and Electronic Materials
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• v.6 no.4
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• pp.144-148
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• 2005

The microstructure and electrical properties of varistor ceramics, which are composed of Zn-Pr­Co-Cr-Dy-oxide system, were investigated at various dysprosia $(Dy_2O_3)$ addition contents. The $DY_2O_3$ microstructurally played the role of inhibition for the densification and grain growth. As the $DY_2O_3$ content increased, the density decreased in the range of $5.51-4.90 g/cm^3$, reaching maximum at $0.5 mol\%$ and the average ZnO grain size decreased in the range of $17.7-6.0{\mu}m$. The incorporation of $DY_2O_3$ significantly improved the nonlinear properties of varistors, above 30 in nonlinear exponent, compared with that without $DY_2O_3$. The varistors with the best performance of nonlinear properties was obtained $DY_2O_3$ content of $1.0 mol\%$, 49 in nonlinear exponent and $0.5{\mu}A$ in leakage current.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1288-1290
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• 2005

We report on the structural and electrical properties of amorphous Yttria-stabilized zirconia (YSZ) thin films which are the potential high-k gate dielectric material of organic thin film transistor (OTFT). To investigate the influence of the oxygen flow rate on the structural and electrical properties of the YSZ films, XRD, XPS, J-E, I-V were carried out in this work. Oxygen vacancies are expected to be the most predominant type of defect in metal-oxide dielectrics. The leakage current density decreased mainly because of the reduction of oxygen vacancies with increasing oxygen flow rate.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.11
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• pp.946-952
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• 2002

The electrical and dielectric characteristics of ZPCCY-based varistor ceramics were investigated in the sintering time range of 1∼3 h. Increasing sintering time deteriorated the nonlinearity, in which nonlinear exponent is decreased from 51.2 to 23.8 and leakage current is increased from 1.3 to 5.6 $\mu$A. As sintering time increases, the donor concentration was decreased in the range of (1.25∼l.73)$\times$10$\^$18/cm$\^$-3/ and the density of interface states is (3.64∼94.19)$\times$10$\^$12/cm$\^$-2/ with increasing sintering time. The increase in sintering time caused tan $\delta$ to increase in the range of 0.043 to 0.062 and relaxation time to increase in the range of 1.55 to 2.23 ㎲.

• Proceedings of the IEEK Conference
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• 2000.11b
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• pp.29-32
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• 2000

Meta1-ferroelectric-insulator-semiconductor(MFIS) devices using Pt/LiNbO$_{3}$/AIN/Si structure were successfully fabricated. AIN thin films were made into metal-insulator-semiconductor(MIS) devices by evaporating aluminum in a dot array on the film surface. The dielectric constant of the AIN film calculated from the capacitance in the accumulation region in the capacitance-voltage(C-V ) characteristic is 8. The gate leakage current density of MIS devices using a aluminum electrode showed the least value of 1$\times$10$^{-8A}$ $\textrm{cm}^2$ order at the electric field of 500㎸/cm. A typica] value of the dielectric constant of MFIS device was about 23 derived from 1MHz capacitance-voltage (C-V) measurement and the resistivity of the film at the field of 500㎸/cm was about 5.6$\times$ 10$^{13}$ $\Omega$.cmcm