• 세라미스트
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• 제3권1호
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• pp.45-52
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• 2000

전자싸이클로트론공명플라즈마 화학기상증착법(ECR-PECVD)에 의한 Pt 및 $RuO_2$ 기판에서의 PZT 박막의 증착특성 및 전기적 특성을 조사하였다. $RuO_2$ 기판에서는 Pt 기판에 비하여 Pb-관련 이차상이 형성되기 쉬웠고, PZT 페로브스카이트 핵생성이 어려웠다. 하지만, $RuO_2$ 기판에서도 금속유기 원료기체의 정확한 유량조절(특히, $Pb(DPM)_2$ 유량)과 Ti-oxide 씨앗층의 도입을 통하여 $450^{\circ}C$의 비교적 낮은 증착온도에서 단일한페로브스카이트 박막 제조가 가능하였으며, $RuO_2$ 기판에서도 미세구조가 향상된 PZT 박막의 경우 $10^{-6}A/cm^2@100kV/cm$의 우수한 누설전류 특성을 나타내었다. 4 가지 전극배열의 PZT 커패시터들 중에서 $RuO_2//RuO_2$ 커패시터는 누설전류밀도가 $10^{-4}A/cm^2@100kV/cm$ 정도로 높았지만, 피로현상은 나타나지 않았다. 일방향 전계 (unipolar) 피로특성에서 나타난 polarization-shift 현상과 양방향 전계 (bipolar) 피로특성의 온도의존성 결과는 PZT 박막내 charged defect의 이동이 어려움을 나타내었다. Bipolar 신호에 의한 피로현상은 인가전계에 의한 분극반전 과정에서 Pt 계면에서 charged defect의 형성과 관련이 있는 것으로 판단되었다. 또한, 상하부 전극물질 이 다른 경우에는 상하부 계면의 charged defect 밀도에 차이가 생겨 내부전계가 형성되는 것으로 판단되었다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 추계학술발표강연 및 논문개요집
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• pp.68-68
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• 2003

SiC는 wide bandgap 물질로서 그 material properties로 인하여, high tmperature, high power, high frequency영역으로의 사용이 기대되는 물질이다. 따라서 SiC에 대한 기본적인 연구와 더불어, 그 소자 제작 및 응용에의 연구가 절실한 시점이다. 이에, SiC 기본적인 소자중 하나인 Schottky diode에 대해 연구하였다. 본 논문은 Schottky contact 물질로써 현재까지 연구가 미비한 Ru을 사용하였다. Ru은 Pt 계열물질로써, 다른 metal에 비하여 열역학적으로 안정하며, 또한 그의 산소 화합물인 RuO2는 다른 oxide에 비하여 전도성 이 높은 장점을 가지고 있다. 따라서 Ru-SiC diode는 이러한 측면에서 연구할 만한 가치가 있다.

• Journal of Electrochemical Science and Technology
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• 제1권1호
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• pp.19-24
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• 2010

Alloying degree is an important structural factor of PtRu catalysts for direct methanol fuel cells (DMFC). In this work, carbon supported PtRu catalysts were synthesized by reduction method using anhydrous ethanol as a solvent and $NaBH_4$ as a reducing agent. Using anhydrous ethanol as a solvent resulted in high alloying degree and good dispersion. The morphological structure and crystallanity of synthesized catalysts were characterized by X-ray diffraction (XRD), high resolution transmission electron microscope (HR-TEM). CO stripping and methanol oxidation reaction were measured. Due to high alloying degree catalyst prepared in anhydrous ethanol, exhibited low onset potential for methanol oxidation and negative peak shift of CO oxidation than commercial sample. Consequently, samples, applying ethanol as a solvent, exhibited not only enhanced CO oxidation, but also increased methanol oxidation reaction (MOR) activity compared with commercial PtRu/C (40 wt%, E-tek) and 40 wt% PtRu/C prepared in water solution.

• 전자공학회논문지D
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• 제35D권3호
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• pp.39-45
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• 1998

SrBi$_{2}$Ta$_{2}$O$_{9}$ (SBT) ferroelectric thin films for nonvolatile memory were prepared on Pt/Ti/SiO$_{2}$/Si and RuO$_{2}$/SiO$_{2}$/Si substrates by RF magnetron sputtering. The dependences of crystalline and electrical properties on the lower electrode type(Pt and RuO$_{2}$) and the annealing temperatures were investigated. SBT films regardless of their electrode types showed typeical Bi layered peroviskite crystal structures. The crystalline quality of as-deposited SBT films was improved by the rapid thermal annealing at 650.deg. C for 30 sec. The remanetn polarization of 2Pr (Pr+-Pr-) of the annealed SBT films deposited on Pt/Ti/SiO$_{2}$/Si substrates were about 11 .mu.C/cm$^{2}$ and 3 .mu.C/cm$^{2}$, respectively. The leakage currents at 3 V bias voltage were about 0.8 .mu.A/cm$^{2}$ for SBT/ Pt/Ti/SiO$_{2}$/Si and about 1 .mu.A/cm$^{2}$ for SBT/RuO$_{2}$/SiO$_{2}$/Si sample. SBT films annealed at 650 .deg. C showed no degradation in Pr values after 10$^{11}$ polarization switching cycles, indicating good fatigue properties. In addition, for SBT samples deposited on Pt/Ti/SiO$_{2}$/Si, Pr values increased to more than that of initial state, suggesting the increament of leakage current caused by repeated polarization.

• 한국세라믹학회지
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• 제34권10호
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• pp.1021-1026
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• 1997

RuO2 thin film has reasonably good conductivity and stiffness and it is thought to substitute for the cantilever beam made up of Pt and Si3N4 double layers in microactuators. Therefore, anisotopic Si etching was performed using RuO2 thin film as a mask layer in 25 wt. % TMAH water solution. In the etching temperature ranging from 6$0^{\circ}C$ to 75$^{\circ}C$, the etch rates of all the crystallographic directions increased linearly as the etching temperature increased. The etch rate ratio(selectivity) of [111]/[100] which varied from 0.08 to 0.14, was not sensitive to temperature. The activation energies for [110] direction, [100] direction and [111] direction were 0.50, 0.66 and 1.04eV, respectively. RuO2 cantilever beam with a clean surface was formed at the etching temperatures of 6$0^{\circ}C$ and $65^{\circ}C$. But the damages due to formation of pin holes on RuO2 surface were observed beyond 7$0^{\circ}C$. The tensile stress of RuO2 thin films caused the cantilever bending upward. As a result, it was demonstrated that the formation of conducting oxide RuO2 cantilever beam which can replace the role of an electrode and supporting layer could be possible by TMAH solution.

• 한국수소및신에너지학회논문집
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• 제20권3호
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• pp.194-201
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• 2009

The e1ectrocatalytic properties of heteropolyacids(HPAs) entrapped in covalently cross-linked sulfonated polyetheretherketone(CL-SPEEK/HPA) membranes have been studied for water electrolysis. The HPAs, including tungstophosphoric acid(TPA), molybdophosphoric acid(MoPA), and tungstosilicic acid(TSiA) were used as additives in the composite membranes. The MEA was prepared by a non-equilibrium impregnation-reduction(I-R) method, using reducing agent, sodium borohydride(NaBH4) and tetraamineplatinum(II) chloride(pt(NH$_3$)$_4$Cl$_2$). The electrocatalytic properties of composite membranes such as the cell voltage were in the order of magnitude CL-SPEEKlMoPA40 (wt%) > /TPA30 > /TSiA40. In the optimum cell applications for water electrolysis, the cell voltage of PtlPEM/Pt-Ru MEA with CL-SPEEKlTPA30 membrane was 1.75 V at 80$^{\circ}$C and I A/cm$^2$ and this voltage carried lower than that of 1.81 V of Nafion 117. Consequently, in regards of electrochemical and mechanical characteristics and oxidation durability, the newly developed CL-SPEEKITPA30 composite membrane exhibited a better performance than the others, but CLSPEEKlMoPA40 showed the best electrocatalytic activity (1.71 Vat 80$^{\circ}$C and 1 A/cm$^2$) among the composite membranes.

• Korean Chemical Engineering Research
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• 제46권4호
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• pp.697-700
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• 2008

본 연구에서는 개미산 연료전지의 연료극에서 Pt 촉매의 안정성과 활성을 높이기 위해 Bi를 UPD법을 이용하여 Pt 촉매 위에 증착시켰다. 증착된 Bi의 활용도를 높이기 위해 다층 전극구조를 적용하였으며, 전자탐침미세분석(EPMA) 결과에서 Bi가 장기성능 실험동안 촉매층에 안정적으로 존재하는 것을 확인할 수 있었다. 연료전지 성능실험에서는 Pt black 촉매 위에 Bi를 UPD한 다층 구조의 전극이 PtRu black 촉매보다 전류밀도 $150mA/cm^2$에서 약 200 mV정도 높은 성능을 나타냈다. Pt black을 40% Pt/C로 대체했을 경우 역시 높은 성능과 장기 안정성을 보였다.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.358-359
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• 2006

Ru-C nano-composite films were prepared by MOCVD, and their microstructures and their electrode properties for oxygen gas sensors were investigated. Deposited films contained Ru particles of 5-20 nm in diameter dispersed in amorphous C matrix. The AC conductivities associating to the interface charge transfer between Ru-C composite electrode and YSZ electrolyte were 100-1000 times higher than that of conventional paste-Pt electrodes. The emf values of the oxygen gas concentration cell constructed from the nano-composite electrodes and YSZ electrolyte showed the Nernstian theoretical values at low temperatures around 500 K. The response time of the concentration cell was 900 s at 500 K.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.394-397
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• 2001

In this paper, in-situ deposited $Ru/RuO_2$ bottom electrodes have been investigated as new bottom electrodes for PZT thin film capacitor application. As a comparison, structural and electrical properties of PZT thin films on Pt/Ti and $RuO_2$ bottom electrodes are also investigated. The use of $Ru/RuO_2$ hybrid electrodes showed better electrical properties in compression with $RuO_2$ bottom electrode. With increasing Ru electrode thickness, the PZT thin films showed preferred orientation along the (110) direction and and leakage current of PZT thin films were improved. The PZT thin films on Ru (100nm)/$RuO_2$ electrodes exhibited excellent ferroelectric properties such as remant polarization and coercive field of $7.2C/cm^2$ and 46.35 kV/cm, respectively.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 유기절연재료 전자세라믹 방전플라즈마 일렉트렛트 및 응용기술
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• pp.58-62
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• 2002

Pb($Zr_{0.52}Ti_{0.48}$)$O_3$ (PZT) thin films deposited on the Pt/Ti and Ru/$RuO_2$ bottom electrode by rf magnetron sputtering methode. Ru/$RuO_2$ bottom electrode deposited on the p-type wafer as Ru thickness by in-situ process. Our results show that all PZT films indicated perovskite polycrystalline structure with perferred orientation (110) and no pyrochlore phase is observed. A well-fabricated $RuO_2$/PZT/Ru(100nm)/$RUO_2$ capacitor showed a leakage current density in the order of $2.13{\times}10^{-7}A/cm^2$ as 100 kV/cm, a remanent polarization of 7.20 ${\mu}C/cm^2$, and a coercive field of 58.37 kV/cm. The results show that the new Ru/$RuO_2$ bottom electrodes are expected to reduce the degradation ferroelectric fatigue and excellent ferroelectric properties.