• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.188-188
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• 2011

MgO는 암염구조의 이온결합성 화합물로 7.8 eV의 높은 띠 틈과 약 95%의 탁월한 투과도를 갖는다. 또한, ${\gamma}$ process에 의한 이차 전자 방출이 높고 이온 스퍼터링에 의한 표면 손상이 적어 면 방전 AC-PDP의 보호막으로 이용된다. 따라서 MgO 보호막에 관한 연구는 이차 전자 방출 계수를 높여 방전 전압을 감소시키고 높은 유전율과 투과도를 유지시키기 위한 목적으로 전개되어지고 있다. 본 연구는 이온 스퍼터링에 의한 MgO 보호막의 표면 특성의 변화를 알아보기 위해 이루어졌다. MgO 박막은 electron beam evaporation의 방법을 통해 챔버 내에 O 기체를 주입하고 P type Si 기판을 300$^{\circ}C$ 가열하여 40 nm 두께로 제작되었다. 박막 시료는 표면분석 전 초고진공챔버 내에서 표면에 산화된 불순물 제거를 위해 550$^{\circ}C$의 열처리가 되어졌다. 그리고 250 eV의 He 이온으로 박막 표면을 스퍼터링 하여 XPS, REELS, UPS를 이용하여 전자 및 광학적 특성을 연구하였다. XPS 분석을 통해 MgO 박막은 He 이온 스퍼터링에 의해 표면의 화학적 조성이 변하지 않는다는 것을 확인했다. MgO 박막에 이온 스퍼터링을 하면 표준 시료와 비교하여 Ep=1,500 eV일 때 7.54 eV에서 7.63 eV로 높아지는 경향이 있다. 일함수는 He 이온 스퍼터링 한 결과 3.85 eV로부터 4.09 eV로 약간 높아졌다. 또한, QUEELS simulation으로 얻은 가시광 투과도는 91~92%로 분석되었다.

• Applied Chemistry for Engineering
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• v.8 no.6
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• pp.1022-1028
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• 1997

This work was performed to study the characteristics of electrochemical intercalation reactions occurring at the interface between the organic electrolyte and tungsten trioxide thin film (thickness of $4000{\AA}$) prepared by e-beam evaporation method as cathodically coloring oxide with regard to the electrochromism by the intercalating reactions of the lithium cation in the 1M $LiClO_4/PC$ organic solution. The characteristics of electrochemical intercalation reactions were investigated by various DC electrochemical methods such as cathodic Tafel polarization test, multiple and the single sweep cyclic voltammetry and the coulomety titrations method. The surfaces of thin films were observed with the patterns of X ray diffraction after the coloring and bleaching reactions. In comparison with the previous results that $WO_3$ thin film intersely detached from the surface of electrode when the hydrogen cation was intercalated into $WO_3$ thin film in the o.1N $H_2SO_4$ aqueous solution, the intercalation reaction of lithium cation into $WO_3$ thin film in the 1M $LiClO_4/PC$ organic solution was shown that the stable bleaching and coloration was appeared within 1.0V of the applied overpotential. When the overpotential of electrochromic reaction for lithium cation in the 1M $LiClO_4/PC$ organic solution had been applied up to 1.5V, the accumulation phenomenon of lithium in amorphous $WO_3$ thin film layer occurred because the inserted lithium into amorphous $WO_3$ thin layer for coloring process was not fully removed from the thin layer to the electrolyte during bleaching process. It was found that there is a limitation of applied overpotential for coloring process by the reduction of the current densities of bleaching and coloration after few number of coloring and bleaching cycles.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.9
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• pp.566-570
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• 2014

Electrode pattern effects on the capacitive humidity sensor were investigated. The fabrication of the capacitive humidity sensor was formed with three steps. The bottom electrode was formed on the silicon substrate with Pt/Ti thin layer by using shadow mask and e-beam evaporator. The photo sensitive polyimide was formed on the bottom electrode by using photolithography process as a humidity sensitive thin film. The upper electrode was formed on the polyimide thin film with Pt/Ti thin layer by using e-beam evaporator and lift-off method. Three electrode patterns, such as circle, square, and triangle pattern, were used and changed the sizes to investigate the effects. The capacitances of the sensors were decreased 622 to 584 pF with the area decreament of patterns 250,000 to $196,250{\mu}m^2$. From these results, a capacitive humidity sensor with photo sensitive polyimide is expected to be applied to a high sensitive humidity sensor.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2002.05a
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• pp.50-50
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• 2002

탄소 박막은 내마모, 화학적 생물학적 적합성 둥의 특성으로 언하여 많은 연구자들레 의하 여 연구되어지고 있다. 그러나 탄소 박막의 경우 높은 잔류응력과 이에 따른 낮은 밀착력으 로 언하여 증착 두께에 제한이 되어왔다. EB-PVD법을 이용하여 탄소막을 증착하는 경우 이러한 문제점을 해결하기 위하여 탄소막에 제 2의 금속원소를 첨가하거나 화합물 형태의 증착원 이용, 복합공정 (Hybrid process)을 통하여 증착 두께 의 제 한을 극복하고자 하는 연 구가 계속되고 있다. 본 연구에서는 탄소막의 잔류응력 제어와 증착 두께를 높이기 위하여 Plasma Activated E E-Beam Evaporation을 통하여 탄소막을 증착하였다. 탄소막 증착시 잔류응려과 밀착력에 대한 플라즈마의 영향올 알아보기 위하여 RF 플라즈마의 인업 전력에 따라 실험을 수행하였으며 필라멘트 전자 방출원을 이용하여 플라즈마 밀도가 미치는 영향도 알아보았다.

• Journal of the Korean institute of surface engineering
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• v.30 no.4
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• pp.223-230
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• 1997

Tungsten oxide and nickel oxide thin films were deposited onto ITO(Indium Tin Oxide) transparent glass by the E-beam evaporation and were used as a cathode and an anode for the EC(Electrochromic) smart window, respectively. Stoichiometric structures of the deposited films were investigated by the implementation of XPS(X-ray Photoelectron Spectroscopy) analysis and the results were $WO_{2.42}$ and $NiO_{0.44}$. This oxygen deficincy might affect affect the transparency of the thin films. The electrolyte for the EC smart windows was PAN-$LiCIO_4$ conducting polymer. EC(Ethylene Carbonate)and PC(Propylene Carbonate) were added as plasticizer to enhance ion conductivity. When the weight ratio of the EC : PC was 3 : 1, transmission difference and cycle life performance were tested. Polymer EC windows showed 40% $\Delta$T at 1.5V operating volage for 3,200 cycles. Structural degradation was observed by the SIMS(Secondary Ion Mass Spectroscopy) analysis and it was confirmed that structural degradation of polymer caused by the solvent evaporation was the main cause to degrade EC smart windows.

• Journal of the Korean Vacuum Society
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• v.8 no.1
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• pp.70-74
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• 1999

MgO-CaO protective layers with various composition were prepared by electron beam evaporation to improve the characteristics of conventional pure MgO thin films as a protective layer for AC-PDP. The maximum deposition rate of pure MgO was 1025 $\AA$/min and decreased with increasing [(CaO/(MgO+CaO)] ratio of evaporation starting materials. From XRD analyses, a trend of peak shift to the lower 2$\theta$ angle side was shown as CaO content increased and it stoped when the concentration of CaO was 0.13, which corresponds to the maximum solubility of CaO in MgO. The optimum composition of the protective thin films was Mg 47.1 at%, Ca 1.3 at%, O 51.6 at%, and firing voltage, memory margin and deposition rate of the film with this composition was 176 V, 0.5 and 515 $\AA$/min, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.617-620
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• 1999

In this study, the polarization e(fecal and the birefringence effect of amorphous germanium (a-Ge) thin films were investigated by using linearly polarized He-Ne laser beam. The a-7e thin films were deposited on the quarts substrate by plasma enhanced chemical vapor deposition (PECVD) and thermal vacuum evaporation In order to obtain the optimum grating arrays, inorganci resists such as Si$_3$N$_4$ and a-Se$_{75}$ Ge$_{25}$ , were prepared with the optimized thickness by Monte Carlo (MC) simulation. As the results of MC simulation, the thickness ofa-Se$_{75}$ Ge$_{25}$ resist was determined with Z$_{min}$ of 360$\AA$ . The resists were exposed to Ga$^{+}$-FIB with accelerating energies of 50 keV, developed by wet etching, and a-Ge thin film was etched by reactive ion-etching (RIE). Finally, we were obtained grating arrays which grating width and linewidth are 0.8${\mu}{\textrm}{m}$, respectively and we studied the polarization and birefringence effect in transmission grating array made of high refractive amorphous material, and the applicability as waveplates and polarizers in optical device.e.e.

• Applied Chemistry for Engineering
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• v.21 no.2
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• pp.224-229
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• 2010

Transparent conductive oxide films have been widely used in the field of flat panel display (FPD). Transparent conductive Indium Zinc Oxide (IZO) thin films with excellent chemical stability have attracted much attention as an alternative material for Indium Tin Oxide (ITO) films. In this study, using $In_2O_3$ and ZnO powder mixture with a ratio of 90 : 10 wt% as a target, IZO films are prepared on polynorbornene (PNB) substrates by electron beam evaporation. The effect of thickness and $O_2$ introduction flow rate on the optical, electrical, structural properties and surface composition of deposited IZO films were investigated by UV/Visible spectrophotometer, 4-point probe method, SEM, XRD and XPS.

• Journal of the Korean Magnetics Society
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• v.9 no.4
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• pp.210-216
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• 1999

The objective of this paper is to investigate corrosion behaviors of CoCrTa/CrNi thin film and post heat-treatment effect. An electron beam evaporator was used for films deposition. After evaporation, post heat-treatment was carried out under $5.0{\times}10^3$ Torr vacuum condition. Annealing temperature and time were 400 $^{\circ}C$ and 30 min, respectively. To understand the effect of annealing on corrosion behavior of CoCrTa/CrNi, potentiodynamic polarization technique and accelerated corrosion chamber test were undertaken. Corrosion potential is higher for the annealed samples (CoCrTa 400$\AA$/CrNi 1000$\AA$) than for as-deposited one. This is attributed to an enrichment of Cr in the surface layer of the thinfilm resulting in a more corrosion resistant material.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.1
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• pp.130-133
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• 2010

Although many structures based on $SnO_2$ nanowires have been demonstrated, there is a limitation towards practical application due to the unwanted contact potential between the metal electrode and the $SnO_2$ nanowire. This is mostly due to the presence of the native oxide layer that acts as an insulator between the metal contact and the nanowire. In this study the contact properties between Ti/Au contacts and a single $SnO_2$ nanowire was compared to the electrical properties of a contact without the oxide layer. RIE(Reactive Ion Etching) is used to selectively remove the oxide layer from the contact area. The $SnO_2$ nanowires were synthesized by chemical vapor deposition (CVD) and dispersed on a $Si/Si_3N_4$ substrate. The Ti/Au (20nm/100nm) electrodes were formed bye-beam lithography, e-beam evaporation and a lift-off process.