• Proceedings of the KIEE Conference
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• 2005.11a
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• pp.189-190
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• 2005

Ploycrystalline $Pb(Zr_{0.5},Ti_{0.5))O_3$ and $BaTiO_3$ powder were prepared by sol-gel process. The alumina substrate were sintered at $1400^{\circ}C$ with bottom electrode of Pt for 2 hours. The Pb(Zr0.5,Ti0.5)O3 / BaTiO3 multilayered thick films with laminating times were fabricated on alumina substrate by screening printing method. The obtained thick films were sintered at $800^{\circ}C$ with upper electrode of Ag paste for 1 hour. Structural properties of Pb(Zr0.5,Ti0.5)O3 / BaTiO3 multilayered thick films were investigated. As a result of the Differential Thermal Analysis(DTA) of Pb(Zr0.5,Ti0.5)O3, exothermic peak was observed at around 650 $^{\circ}C$. The X-ray diffraction (XRD) patterns indicated that BaTiO3 and Pb(Zr0.5,Ti0.5)O3 phases and porosities were formed in the interface of Pb(Zr0.5,Ti0.5)O3 / BaTiO3multilayered thick films.

• Journal of the Korean institute of surface engineering
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• v.40 no.1
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• pp.6-10
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• 2007

For low-emissivity application on window glass, coalescence of thin film silver islands is crucial for high transmittance in the visible and high reflectance in the infrared. It is well known that the underlayer affects the growth mode. In this work, the effect of the underlayer on the growth of silver films deposited by filtered cathodic vacuum arc is discussed. While a nominal 0.1 nm niobium underlayer has promoted the coalescence of silver islands, a 0.2 nm layer did not show these features. From a thermodynamic approach, Nb seeding less one monolayer is considered to reduce the surface energy between the silver atoms and $Nb/TiO_2$ surface, resulting the change of its growth from 3D islands to 2D-layer modes. If the seed layer exceeds one monolayer, however, a rougher surface is formed because the surface energy of Nb itself is superior to that of $Nb-TiO_2$. The onset of silver layer on the roughened Nb surface is required more silver.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.11a
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• pp.35-42
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• 2001

Nanotribological characteristics between a Si$_3$N$_4$ AFM tip and hydrophobic thin films were experimentally studied. Tests were performed to measure the nano adhesion and friction in both AFM(atomic force microscope) and LFM(lateral force microscope) modes in various ranges of normal load. Plasma-modified thin polymeric films were deposited on Si-wafer (100). Results showed that wetting angle of plasma-modified thin polymeric film increased with the treating time, which resulted in the hydrophobic surface and the decrease of adhesion and friction. Nanotribological characteristics of these surfaces were compared with those of other hydrophobic surfaces, such as DLC, OTS and IBAD-Ag coated surfaces. Those of OTS coated surface was superior to those of others, though wetting angle of plasma-modified thin polymeric film is higher.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.6
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• pp.497-504
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• 2014

The digital signage display is actively researched as the next generation of large FPD. To commercialize those digital signage display, the manufacturing cost must be downed with printing method instead of conventional photolithography. Here, we demonstrate a reverse offset printed TFT electrodes for the digital signage display. For the fabricated source/drain and gate electrode, we used Ag ink, silicone blanket, Clich$\acute{e}$ and reverse offset printer. We printed uniform TFT electrode patterns with narrow line width(10 ${\mu}m$ range) and thin thickness(nm range). In the end the printing source/drain and gate electrode are successfully achieved by optimization of experimental conditions such as Clich$\acute{e}$ surface treatment, ink coating process, delay time, off/set process and curing temperature. Also, we checked that the printing align accuracy was within 5 ${\mu}m$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.96-98
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• 1999

유기전계발광소자(OELD)의 성능 향상을 위한 많은 연구가 진행되고 있지만 아직까지 금속전극과 유기발 광층 사이의 접촉저항(Contact Resistance)에 관한 연구는 거의 보고되지 않고 있다. Ohmic 접합에서 접촉 저항은 효율적이고 신뢰성 있는 소자제작에 있어서 간과되어서는 안될 매우 중요한 부분이다. 본 연구에서는 금속전극과 유기발광충 사이의 접촉저항에 관해서 논의하고자 한다. 본 연구에서 제작된 샘플은 금속전극으로 Ag, 유기발광재료로서 Alq$_3$를 사용하였으며, Alq3의 두께를 100 $\AA$에서 500 $\AA$까지 각각 다르게 하여 서로 다른 두께의 유기발광층을 가지는 샘플을 제작하였다. 금속전극의 매트릭스 구조에 의해 형성된 적선의 크기는 3 mm x 2 mm이며, 제작된 샘플의 접촉비저항은 TLM(Transmission Line Measurement) 방법을 이용하여 구하였다. Planar한 TLM model로부터 새로운 vertical model을 유추하였으며, 이를 근거로 접촉저항 및 transfer length 등을 계산하였다. 상온에서 측정된 전체 저항값은 유기발광층의 두께가 증가함 에 따라 증가하는 경향을 나타냈으며, 이 때 계산된 접촉비저항은 1.49$\times$$10^1$ $\Omega$-$\textrm{cm}^2$ 이다. 접촉저항은 전극 사이의 거리의 증가에 따라 증가하지만, 측정시간의 thermal budget의 영향으로 상대적으로 전체저항이 감 소하였으나, 저항감소분의 포화에 따라서, 거리에 비례하여 다시 저항이 증가하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.329-332
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• 1999

In this paper, BST((Bao.&o,dTi0:3) thin films were deposited by the rf magnetron sputtering method on Pt/$SiO_2$/Si substrate. Pt, $RuO_2$, Ag, Cu films for the formation of top electrode were deposited on BST thm films. And then Top Electrodes/BST/Pt capacitors were annealed with rapid thermal annealing(RTA) at various temperature. We have investigated effect of post-annealing on the electrical properties such as dielectric constant and leakage current of the capacitors. It was found that electrical properties of the capacitors were greatly depended on the annealing temperatures as well as the materials of top electrodes. In BST thin films with Pt top electrode was annealed at $700^{\circ}C$. the dielectric constant was measured to the value of 346 at l[kHzl and the leakage current was obtained to the value of $8.76\times10^8$[A/$\textrm{cm}^2$] at the forward bias of 2[V].

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.20.2-20.2
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• 2009

최근 무전해 식각법을 이용한 실리콘 나노와이어 합성이 다양한 각도에서 이루어지고 있다. 무전해 식각법을 통한 나노와이어 합성은, 단결정 실리콘 기판에 촉매를 올려 기판을 식각할 수 있는데, 이 방법을 이용하여 넓은 면적의 수직방향으로 배열된 10 ~ 300nm 지름의 단결정 실리콘 나노와이어를 합성할 수 있다. 본 연구에서는 무전해 식각법으로 boron이 도핑된 p-type실리콘 기판을 식각하여 실리콘 나노와이어를 합성하였고, 단일 나노와이어의 field-effect transistor(FET) 소자가 가지는 전기적 특성에 대하여 분석하였다. 특히 무전해 식각법을 이용하여 나노와이어를 합성할 때, 촉매로 사용되는 Ag particle이 나노와이어에 미치는 영향에 대해서 분석해 보았다. FET 소자의 게이트 절연막은 가장 일반적으로 사용되는 SiO2 (300nm)와 고유전체로 잘 알려진HfO2(80nm)를 사용하여 전기적 특성을 비교하여 보았다. 한편, HfO2 박막은 atomiclayer deposition(ALD)장비를 이용하여 증착하였다. 합성된 실리콘 나노와이어의 경우 X-ray diffraction(XRD)로 결정성을 확인하였으며, high-resolution transmission electron microscopy(HRTEM)으로 결정성 및 나노와이어의 표면 형태를 확인하였다. 전기적 특성은 I-V 측정을 통하여 Ion/Ioff ratio, 이동도, subthreshold swing, subthreshold voltage값을 평가하였다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.6
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• pp.538-546
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• 2006

We report on characteristics of specially designed inductively-coupled-plasma chemical vapor deposition (ICP-CVD) system for top-emitting organic light emitting diodes (TOLEDs). Using high-density plasma on the order of $10^{11}$ electrons/$cm^3$ generated by linear-type antennas connected in parallel and specially designed substrate cooling system, a 100 nm-thick transparent $SiN_{x}$ passivation layer was deposited on thin Mg-Ag cathode layer at substrate temperature below $50\;^{\circ}C$ without a noticeable plasma damage. In addition, substrate-mask chucking system equipped with a mechanical mask aligner enabled us to pattern the $SiN_x$ passivation layer without conventional lithography processes. Even at low substrate temperature, a $SiN_x$ passivation layer prepared by ICP-CVD shows a good moisture resistance and transparency of $5{\times}10^{-3}g/m^2/day$ and 92 %, respectively. This indicates that the ICP-CVD system is a promising methode to substitute conventional plasma enhanced CVD (PECVD) in thin film passivation process.

• Electrical & Electronic Materials
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• v.7 no.5
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• pp.389-396
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• 1994

The bilayer film of Ag/a-S $e_{75.G}$ $e_{25}$ and the monolayer film of a-S $e_{75.G}$ $e_{25}$ act as a negative-type and a positive-type resist in focused ion beam lithography, respectively. Using a model which takes into account the ion stopping power, the ion projected range, the ion concentration implanted into resists and the ion transmission coefficient, etc., the ion resist parameters are calculated for a broad range of ion energies and implanted doses. Ion sources of A $r^{+}$, S $i^{++}$ and G $a^{+}$ are used to expose resists. As the calculated results, the energy loss per unit distance by Ga'$^{+}$ ion is about 10$^{3}$[keV/.mu.M] and nearly constant for all energy range. Especially, the projected range and struggling for 80[keV] G $a^{+}$ ion energy are 0.0425[.mu.m] and 0.020[.mu.m], , respectively and the resist thickness of a-S $e_{75}$ G $e_{25}$ to minimize the ion penetration rate into a substrate is 0.118[.mu.m].u.m]..u.m].

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.1960-1961
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• 2005

Ploycrystalline $Pb(Zr_{0.5},Ti_{0.5})O_3$ and $BaTiO_3$ powder were prepared by sol-gel process. The alumina substrate were sintered at $1400^{\circ}C$ with bottom electrode of Pt for 2 hours. The Pb(Zr0.5, Ti0.5)O3/BaTiO3 multilayered thick films with laminating times were fabricated on alumina substrate by screening printing method. The obtained thick films were sintered at $800^{\circ}C$ with upper electrode of Ag paste for 1 hour, Structural properties of Pb(Zr0.5,Ti0.5)O3/BaTiO3 multilayered thick films were investigated. As a result of the Differential Thermal Analysis(DTA) of Pb(Zr0.5,Ti0.5)O3, exothermic peak was observed at around $650^{\circ}C$. The X-ray diffraction (XRD) patterns indicated that BaTiO3 and Pb(Zr0.5,Ti0.5)O3 phases and porosities were formed in the interface of Pb(Zr0.5,Ti0.5)O3 / EaTiO3 multilayered thick films.