• Korean Journal of Materials Research
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• v.28 no.10
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• pp.595-600
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• 2018

This study investigates the microstructural properties of CoCrFeMnNi high entropy alloy (HEA) oxynitride thin film. The HEA oxynitride thin film is grown by the magnetron sputtering method using nitrogen and oxygen gases. The grown CoCrFeMnNi HEA film shows a microstructure with nanocrystalline regions of 5~20 nm in the amorphous region, which is confirmed by high-resolution transmission electron microscopy (HR-TEM). From the TEM electron diffraction pattern analysis crystal structure is determined to be a face centered cubic (FCC) structure with a lattice constant of 0.491 nm, which is larger than that of CoCrFeMnNi HEA. The HEA oxynitride film shows a single phase in which constituting elements are distributed homogeneously as confirmed by element mapping using a Cs-corrected scanning TEM (STEM). Mechanical properties of the CoCrFeMnNi HEA oxynitride thin film are addressed by a nano indentation method, and a hardness of 8.13 GPa and a Young's modulus of 157.3 GPa are obtained. The observed high hardness value is thought to be the result of hardening due to the nanocrystalline microstructure.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.3
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• pp.253-258
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• 2005

This paper presents characteristics of CrOx thin-film, which were deposited on $Al_2$O$_3$ wafer by DC reactive magnetron sputtering in an argon-oxide atmosphere for high temperature applications. The present paper deals with a study of the technological characteristics of thin film resistors to provide a control in obtaining temperature coefficients of resistance of given value. The optimized condition of CrOx thin-film were thickness range of 2500 $\AA$ and annealing condition(350 $^{\circ}C$, 1 hr) in oxide partial pressure(3.5${\times}$10$^{-4}$ torr). Under optimum conditions, the CrOx thin-films is obtained a high resistivity, p=340 $\mu$Ωcm, a low temperature coefficient of resistance, TCR=-55 ppm/$^{\circ}C$. The CrOx thin films resistors which were fabricated in this paper had excellent characteristics as high precision resistors.

• Korean Journal of Materials Research
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• v.17 no.6
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• pp.308-312
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• 2007

Chromium oxide thin films have been deposited on silicon substrates using a tabletop 9kJ mathertyped plasma focus (PF) device. Before deposition, pinch behavior with gas pressure was observed. Strength of pinches was increased with increasing working pressure. Deposition was performed at room temperature as a function of working pressure between 50 and 1000 mTorr. Composition and surface morphology of the films were analyzed by Auger Electron Spectroscopy and Scanning Electron Microscope, respectively. Growth rates of the films were decreased with pressure. The oxide films were polycrystalline containing some impurities, Cu, Fe, C and revealed finer grain structure at lower pressure.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.8
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• pp.634-639
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• 2001

We investigated the etching characteristics of chromium films by using Cl$_2$/O$_2$ gas mixtures with electron cyclotron resonance plasma. In order to examine the chemical etch characteristics of Cr films by using Cl$_2$/O$_2$ gas plasma, we obtained the etch rate with various gas mixing ratios. By X-ray photoelectron spectroscopy, the surface reaction on the chromium films during the etch was examined. From narrow scan analyses of Cr, Cl, and O, it was confirmed that a chromium oxychlorie (CrCl$_{x}$O$_{y}$) layer was formed on the surface by the etch using Cl$_2$/O$_2$ gas mixtures. We observed a new characteristic emission line during the etch of chromium films using Cl$_2$/O$_2$ gas mixtures by an optical emission spectroscopy. It was found that the peak intensity of this emission line had a tendency compatible with the etch rate. The origin of this emission line was discussed in detail. At the same time, the etched profile was also examined by scanning electron microscope.e.e.

• The Journal of the Korea Contents Association
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• v.9 no.10
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• pp.451-463
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• 2009

The purpose of this research is to develop thin film materials and fabrication process for efficient $TiO_2$/CdTe solar cells. In this work photocatalyst titanium dioxide was prepared by sol-gel procedure according to reaction condition, the mole ratio of $H_2O$/TTIP, pH of solution and aging condition of powder. The prepared titanium dioxide was thermally treated from 300 to $750^{\circ}C$. Maximum intensity of anatase phase of titanium dioxide was achieved by calcination at $600^{\circ}C$ for 2 hr. And it was mixture of anatase and rutile phase when temperature of calcination was $750^{\circ}C$. It has been known that the properties of synthesized titanium dioxide according to aging time and calcination temperature was converted to anatase phase crystal on increasing of aging time. Also the current density has been increased with aging time and temperature, the efficiency has been increased with because of reason on above results. The formation of chemical bonding on oxygen and cadmium telluride under oxygen circumstances had been observed, and oxygen of thin film surface on cadmium telluride had been decreased with the treatment of chromate and hydrazine. As results had been shown that the energy conversion efficiency of cadmium telluride use by rapidly treatmented heat at the condition of $550^{\circ}C$ under air circumstance got 12.0%, 6.0% values according to $0.07cm^2$, $1.0cm^2$ surface area, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.116-116
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• 2007

21 세기에 접어들면서 인터넷을 통한 정보 통신의 발달과 개인 휴대용 이동 통신기기의 활발한 보급에 따라 휴대형 전자기기들의 소형화와 고성능화로 나아가고 있다. 이러한 전자기기에 사용될 IC의 내장 메모리 또한 집적화 및 고속화, 저 전력화가 이루어져야 한다. 이러한 전자기기들에 필수적인 압전 세라믹스 부품 중 압전 부저 및 기타 음향 부품등을 각종 전자기기와 무선 전화기에 채택함으로써 압전 부품에 대한 수요와 생산이 계속 증가할 것으로 전망된다. 이처럼 압전 세라믹스를 이용한 그 응용 범위는 대단히 방대하며, 현재 모든 압전 부품들은 PZT 계열 재료로 만들어지고 있고, 차후 모두 비납계열 재료로 대체될 것이 확실시된다. Pb의 환경오염은 이미 오래전부터 큰 문제점으로 인식되고 있었으며 그 일례로 미국의 캘리포니아 주에서는 1986년부터 약 800종의 유해물질, 그 중에서도 Pb 사용을 300ppm 이하로 규제하는 Proposition 65를 제정하여 실행하고 있다. 그리고 2003년 2월에 EU (European Union) 에서 발표한 전자산업에 관한 규제 사항중 하나인 위험물질 사용에 관한 지칭 (Restriction of Hazardous Substance, RoHS) 에 의하면, 2006 년 7월부터 전기 전자 제품에 있어서 위험 물질인 Pb을 포함한 중금속 물질(카드늄, 수은, 6가 크롬, 브롬계 난연재)의 사용을 금지한다고 발표하였다. 비록 전자세라믹 부품에 함유된 Pb는 예외 사항으로 두었지만 대체 가능한 물질이 개발되면 전자세라믹 부품에서도 Pb의 사용을 금지한다고 규정하였다. 더욱이 일본은 2005 년부터 Pb 사용을 금지시켰다. 이와 같이 Pb가 환경에 미치는 영향 때문에 비납계 강유전 물질 및 압전 세라믹스 재료에 대한 연구가 전 세계적으로 활발히 진행되고 있다. 본 연구에서는 비납계 강유전체의 patterning을 위해서, NKN 박막을 고밀도 플라즈마원인 ICP를 이용하여 식각 mechanism을 연구하고, 식각변수에 따른 식각 공정을 최적화에 대하여 연구하였다. 가스 혼합비에 따라 식각 할때 700 W의 RF 전력과 - 150 V의 직류 바이어스 전압을 인가하였고, 공정 압력은 2 Pa, 기판 온도는 $23^{\circ}C$로 고정하였다. 식각 속도는 Tencor사의 Alpha-step 500을 이용하여 측정되었으며 식각 시 NKN 박막 표면과 라디칼과의 화학적인 반응을 분석하고 식각 메커니즘을 규명하기 위하여 XPS(x-ray photoelectron spectroscopy)를 사용하였다.

• Polymer(Korea)
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• v.27 no.4
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• pp.275-284
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• 2003

The positive temperature coefficient (PTC) effects of high density polyethylene (HDPE)/carbon black composite materials were investigated by enhancing adhesive characteristics of electrodes and controlling HDPE chemical crosslinking. When the silver paste was used as an electrode for the same 45 wt% HDPE/carbon composites, the resistance was over 1 $\Omega$, which should be compared with the resistance of 0.2 $\Omega$ for the dendritic copper electrode. In general, the silver-paste electrode exhibited higher electrical resistance than cupper electrode due to the interfacial resistance between the electrode and PTC composites. The HDPE/carbon composite exhibited typical PTC characteristics maintaining a constant resistance up to vicat point and showing a maximum at the melting point of HDPE. The crosslinked HDPE significantly decreased the negative temperature coefficient (NTC) phenomena, and desirably showed a constant or slightly increasing feature of electrical resistance in the high temperature region.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.74-78
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• 2003

Multi-channel images of 11-MUA and 11-MUOH self-assembled monolayers were obtained by using two-dimensional surface plasmon resonance (SPR) absorption. Patterning process was simplified by exploiting direct photo-oxidation of thiol bonding (photolysis) instead of conventional photolithography. Sharper images were resolved by using a white light source in combination with a narrow bandpass filter in the visible region, minimizing the diffraction patterns on the images. The line profile calibration of the image contrast caused by different resonance conditions at each points on the sensor surface (at a fixed incident angle) enables us to discriminate the monolayer thickness in sub-nanometer scale. Furthermore, there is no signal degradation such as photo bleaching or quenching which are common in the detection methods based on the fluorescence.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.4
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• pp.20-25
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• 2010

An integrated Mach-Zehnder interferometric sensor operating at 632.8 nm was designed and fabricated by the technology of planar rib waveguides. Rib waveguide based on silica system ($SiO_2-SiO_xN_y-SiO_2$) was geometrically designed to have single mode operation and high sensitivity. It was structured by semiconductor fabrication processes such as thin film deposition, photolithography, and RIE (Reactive Ion Etching). With the power observation, propagation loss measurement by cut-back method showed about 4.82 dB/cm for rib waveguides. Additionally the chromium mask process for an etch stop was employed to solve the core damaging problem in patterning the sensing zone on the chip. Refractive index measurement of water/ethanol mixture with this device finally showed a sensitivity of about $\pi$/($4.04{\times}10^{-3}$).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.475-480
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• 2017

In this paper, the conductivity of the fine pattern is improved in the insulating substrate by laser-induced forward transfer (LIFT) process. The high laser beam energy generated in conventional laser induced deposition processes induces problems such as low deposition density and oxidation of micro-patterns. These problems were improved by using a polymer coating layer for improved deposition accuracy and conductivity. Chromium and copper were used to deposit micro-patterns on silicon wafers. A multi-pulse laser beam was irradiated on a metal thin film to form a seed layer on an insulating substrate(SiO2) and electroless plating was applied on the seed layer to form a micro-pattern and structure. Irradiating the laser beam with multiple scanning method revealed that the energy of the laser beam improved the deposition density and the surface quality of the deposition layer and that the electric conductivity can be used as the microelectrode pattern. Measuring the resistivity after depositing the microelectrode by using the laser direct drawing method and electroless plating indicated that the resistivity of the microelectrode pattern was $6.4{\Omega}$, the resistance after plating was $2.6{\Omega}$, and the surface texture of the microelectrode pattern was uniformly deposited. Because the surface texture was uniform and densely deposited, the electrical conductivity was improved about three fold.