• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 Techno-Fair 및 추계학술대회 논문집 전기물성,응용부문
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• pp.171-172
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• 2008

$(Ba_{0.57}Sr_{0.33}Ca_{0.10})TiO_3$ (BSCT) thick films doped with 0.1 mol% $MnCO_3$ and $Yb_2O_3$ ($0.1{\sim}0.7$ mol%) were fabricated by the screen printing method on the alumina substrate. And the structural and electrical properties as a function of $Yb_2O_3$ amount were investigated. The lattice constants of the BSCT thick film doped with 0.1 mol% is 0.3955 nm. The specimen doped with 0.7 mol% $Yb_2O_3$ showed dense and uniform grains with diameters of about 6.3 mm. The thickness of all BSCT thick films was approximately 60 mm. The Curie temperature of the BSCT specimen doped with 0.1 mol% $Yb_2O_3$ was $18^{\circ}C$, and the dielectric constantand dielectric loss at this temperature was 4637 and 4.2%, respectively. The BSCT specimen doped with 0.1 mol% $Yb_2O_3$ showed the maximum value of $349{\times}10^{-9}C/cm^2K$ at Curie temperature. The figure of merit $F_D$ for specific detectivity of the specimens doped with 0.1 mol% $Yb_2O_3$ showed the highest value of $10.9{\times}10^{-9}Ccm/J$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
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• pp.300-304
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• 2002

We fabricated thick film monopole antennas using Mo-doped $BiNbO_{4}$ ceramics and investigated their electrical properties as a function of the Mo-doping concentration. Compared with undoped $BiNbO_{4}$ ceramics, 10 at.% Mo-doping improved microwave dielectric properties of ceramics by increased sintered density as well as decreased space charge density. Further increase in the Mo-doping concentration caused formation of $Bi_{2}MoO_{6}$ phases, resulting in deterioration of the microwave characteristics. The gain and bandwidth of the ceramic monopole antenna were also greatly affected by the Mo-doping concentration. When Mo-doping concentration was 10 at%, highest gain of ~0.7dBi with lowest bandwidth of 30% at 2.3GHz was obtained.

• 센서학회지
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• 제17권6호
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• pp.418-424
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• 2008

The PZT based piezoelectric thick films prepared by screen printing method have been mainly used as a functional material for MEMS applications due to their compatibility of MEMS process. However the screen printed thick films generally reveal poor electrical and mechanical properties because of their porous microstructure. To improve microstructure we mixed attrition milled powder with ball milled powder of 0.01Pb$(Mg_{1/2}W_{1/2})O_3$-0.41Pb$(Ni_{1/3}Nb_{2/3})O_3$-$0.35PbTiO_3$-$0.23PbZrO_3$+0.1 wt% ${Y_2}{O_3}$+1.5 wt% ZnO composition. By mixing 25 % of attrition milled powder and 75 % of ball milled powder, the broadest particle size distribution was obtained, leading to a dense thick film with crack-free microstructure and improved dielectric properties. The X-ray diffraction analysis revealed that the film was in wellcrystallized perovskite phase. The remanent polarization was increased from $13.7{\mu}C/cm^2$ to $23.3{\mu}C/cm^2$ at the addition of 25 % attrition milled powder.

• 마이크로전자및패키징학회지
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• 제8권3호
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• pp.69-75
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• 2001

후막광식각 기술은 스크린 인쇄 등의 일반적 후막공정에 노광 및 현상등의 리소그라피 공정 을 접목시킨 새로운 기술이다. 그린시트를 적층한 후 감광성 Ag 페이스트를 도포하고, 패턴을 노광, 현상, 동시소성하여 스크린 인쇄법으로는 어려운 25 $\mu\textrm{m}$ 선폭과 25 $\mu\textrm{m}$ 선간공백을 구현하였다. 알루미나 기판을 사용하였을 경우에도 유사한 방법으로 20 $\mu\textrm{m}$에 가까운 선폭이 구현 가능하였으며, 노광량과 현상시간이 미세라인 형성에 있어서 가장 중요한 공정변수임을 확인하였다. 또한, 광식각 기술을 이용하여 정밀도가 높고 고주파 대역에서 전송특성이 우수한 microstrip 전송선로와 series gap 공진기를 제작하여, 이로부터 기판의 유전률 및 유전손실을 계산하였다.

• Journal of Information Display
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• 제4권2호
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• pp.1-6
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• 2003

In this paper, we demonstrate that the organic electrophosphorescent device is driven by the organic thin film transistor with spin-coated photoacryl gate insulator. It was found that electrical output characteristics in our organic thin film transistors using the staggered-inverted top-contact structure showed the non-saturated slope in the saturation region and the sub-threshold nonlinearity in the triode region, where we obtained the maximum power luminance that was about 90 $cd/m^2$. Field effect mobility, threshold voltage, and on-off current ratio in 0.45 ${\mu}m$ thick gate dielectric layer were 0.17 $cm^2/Vs$, -7 V, and $10^6$ , respectively. In order to form polyimide as a gate insulator, vapor deposition polymerization process was also introduced instead of spin-coating process, where polyimide film was co-deposited by high-vacuum thermal evaporation from 4,4'-oxydiphthalic anhydride (ODPA) and 4,4'-oxydianiline (ODA) and cured at 150${\sqsubset}$for 1hr. It was also found that field effect mobility, threshold voltage, on-off current ratio, and sub-threshold slope with 0.45 ${\mu}m$ thick gate dielectric films were 0.134 $cm^2/Vs$, -7 V, and $10^6$ A/A, and 1 V/decade, respectively.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.35-36
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• 2006

The influence of the concentration of precursor solution and the number of solution coatings on the densification of the Pb($Zr_xTi_{1-x}$)$O_3$(PZT) thick films was studied. PZT powder and PZT precursor solution were prepared by sol-gel method and PZT thick films were fabricated by the screen-printing method on the alumina substrates. The powder and solution of composition were PZT(70/30) and PZT(30/70), respectively. The coating and drying procedure was repeated 4 times. And then the PZT precursor solution was spin-coated on the PZT thick films. A concentration of a coating solution was 0.5 to 2.0 mol/L[M] and the number of coating was repeated from 0 to 6. The relative dielectric constant of the PZT thick film was increased with increasing the number of solution coatings and the thick films with 15M, 6-time coated showed the 698. The remanent polarization of the 1.5M, 6-time coated PZT thick films was 38.3 ${\mu}C/cm^2$.

• 한국전기전자재료학회논문지
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• 제37권2호
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• pp.119-132
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• 2024

Dielectric ceramic capacitors present high output power density due to the fast energy charge and discharge nature of dielectric polarization. By forming dense ceramic films with nano-grains through the Aerosol Deposition (AD) process, dielectric ceramic capacitors can have high dielectric breakdown strength, high energy storage density, and leading to high power density. Dielectric capacitors fabricated by AD process are expected to meet the increasing demand in applications that require not only high energy density but also high power output in a short time. This article reviews the recent progress on the dielectric ceramic capacitors with improved energy storage properties through AD process, including energy storage capacitors based on both leadbased and lead-free dielectric ceramics.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제55권8호
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• pp.392-398
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• 2006

The properties of tunable dielectric materials on RF frequency band are important high tunability and low loss for RF variable devices, variable capacitor, phased array antenna and other components application. Various composite of BST(barium strontium titanate) ratio combined with other non-electrical active oxide ceramics have been formulated for such uses. We present the tunable properties and Curie temperature on BST thick films. The grain growth of the weight ratio of $BaTiO_3$ increased. This can be explained by the substitute $Sr^{2+}$ ion for $Ba^{2+}$ ion in the $BaTiO_3$ system. The Curie temperature was shifted to lower temperature with increasing $SrTiO_3$in the $BaTiO_3-SrTiO_3$ system, because of decreasing the lattice constant. Also, the dielectric constant, tunability and K-factor of $(Ba_xSr_{1-x})TiO_3$ at over the Curie temperature decreased, at over the $60^{\circ}C$ fixation, maximum dielectric constant at Curie temperature and hence sharper phase transformation occurred at Curie temperature. The result were interpreted as a process of internal stress relaxation resulting form the increase of $90^{\circ}$ domains induced the BST. As a result, It is concluded that over the Curie temperature, frequency response and DC field effect for the tunable properties of BST thick film are suppressed by the transition broadening. For the application of tunable devices, that the curie temperature was investigated to be increased.

• 전자공학회논문지A
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• 제29A권9호
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• pp.29-35
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• 1992

Dielectric thin film of N/O (Si$_{3}N_[4}/SIO_{2}$) for high density stacked dynamic-RAM cell was formed by LPCVD and oxidation(Dry & pyrogenic oxidation methods) of the top Si$_{3}N_[4}$ film. The thickness, structure and composition of this film were measured by ellipsometer, high frequency C-V meter, high resolution TEM, AES, and SIMS. The thickness limit of Si$_{3}N_[4}$ film in making thin N/O structure layer was 7nm. In this experiment, the film with thinner than 7nm was not thick enough as oxygen diffusion barrier, and oxygen punched through the film and interfacial oxidation occurred at the phase boundary between Si$_{3}N_[4}$ and polycrystalline silicon electrode.

• 한국광학회지
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• 제14권3호
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• pp.266-271
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• 2003

수 $\mu\textrm{m}$ 이상의 두께를 가지는 비교적 두꺼운 박막의 경우 박막에 의한 간섭효과로 인하여 나타나는 반사율 스펙트럼에서의 진동주기로부터 막의 두께를 얻는다. 대개 빠른 데이터 처리를 위해서 고속 푸리에 변환(Fast Fourier Transformation, FFI)을 사용하여 진동주기(또는 진동수)를 구한다. 본 연구에서는 반사율 또는 투과율 스펙트럼을 빛의 에너지 축상에서 푸리에 변환하는 종래의 방법을 개선하여 박막의 굴절률 분산을 반영하는 수정된 고속 푸리에 변환 방법을 최초로 도입하였다. 이 새로운 방법은 굴절률 분산에서 유래하는 유효굴절률 결정에서의 오차를 줄여주고 푸리에 변환 피크의 폭 넓어짐을 막아줌으로써 막 두께 결정의 정밀도를 크게 향상시킨다. 수정된 고속 푸리에 변환방법을 80 $\mu\textrm{m}$의 덮게층과 13 $\mu\textrm{m}$의 사이층이 있는 시료의 반사 스펙트럼에 적용하여 고 타당성을 확인하였다.