• 대한전자공학회논문지
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• 제22권4호
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• pp.76-83
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• 1985

RMOS(refractory metal oxide semiconductor)의 게이트와 집적회로의 각 소자나 회로를 연결하는 연결선으로 사용되는 Mo2N/Mo 이중층을 Ar과 N2의 혼합가스 분위기에서 저온의 고주파 반응성스펏터링으로 형성하였다. 1000Å-Mo2N/4000Å-Mo이중층의 면저항은 약 1.20∼1.28Ω/구로서 다결정실리콘의 약 1/10정도가 되었다. C-V측정으로부터 Mo2N/Mo이중층과 비저항이 6∼9Ω·㎝이고 결정면이 (100)인 P형 Si과의 일함수차 f%5는 약 -0.30ev 및 산화층에 존재하는 고정전하밀도 Qss/q는 약 2.1x1011/cm를 얻었다. 인버터 한개당의 신호전달 지연시간을 측정하기 위해 다결정실리콘게이트 NMOS 제조공정을 웅용하여 45개의 인버터로 구성된 ring oscillator를 제작하였다. 본 실험에서 얻을 수 있었던 인버터 한개에 대한 신호전달지연시간은 약 0.8nsec였다.

• 소성∙가공
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• 제18권2호
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• pp.166-171
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• 2009

In this paper, a basic study on micro cutting process with SM20C at low temperature environment was performed. In macro cutting fields, the cryogenic cutting process has been applied to cut the refractory metal but, the serious problem may be generated in micro cutting fields by the cryogenic environment. However, if the proper low temperature is applied to micro cutting area, the cooling effect of cutting heat is expected. Such effect can make the reduction of tool wear and burr formation. For verifying this possibility, the micro cutting experiment at low temperature was performed and SEM images were analyzed.

• 한국결정학회지
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• 제5권1호
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• pp.39-50
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• 1994

Hot Tungsten Filament법에 의해 실리콘(Si), 몰리브데늄(Mo), 타이타늄(Ti), 텅스텐(W) 기판 위에 다이아몬드 박막을 증착시시키고 SEM, X선 회절분석 및 Raman spectroscopy로 분석하였다. 증착시간에 따른 증착실험의 결과로부터 내열금속위에 증착한 다이아몬드박막의 경우에는 먼저 탄화물 층이 형성되고, 그 이후에 다이아몬드가 핵형성되어 성장함을 알 수 있었다. 내열금속에 증착한 다이아몬드 박막은 5기판 위에 증착한 것과 비교할 때, 핵이 많이 형성되었고 facet이 잘 발달된 입자가 적었다. 5기판 뿐만 아니라 내열금속 기판 위에 다이아몬드막을 증착시킬 경우, 다이아몬드의 Raman 피크는 천연 다이아몬드에 비해 높은 주파수쪽으로 이동되었다. 이와같은 Raman 피크의 이동은 다이아몬드와 기판 사이의 열충격보다는 완충층의 역활을 하는 탄화물과 다이아몬드 사이의 열충격을 고려할 때 효과적으로 설명이 가능하였다. 생성된 탄화물의 형태와 다이아몬드 사이에 열충격이 가장 큰 Mo기판의 경우, 다이아몬드 Rarirm 피크의 이동이 가장 크게 나타났으며 Ti, W, Si기판의 순서로 이동이 적게 관찰되었다.

• 소성∙가공
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• 제8권3호
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• pp.233-233
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• 1999

To investigate the effect of tungsten addition on mechanical properties, we prepared refractory (62χ)Nb-18Si-l00Mo-l0Ti-χW (χ=0, 5, 10 and 15 mol.%) in-situ composites by the conventional arc-casting technique, and then explored the microstructure, hardness and elastic modulus at ambient temperature and tensile properties at 1670 K. The microstructure consists of relatively fine (Nb, Mo, W, Ti)/sub 5/Si₃, silicide and a Nb solid solution matrix, and the fine eutectic microstructure becomes predominant at a Si content of around 18 mol.%. The hardness of (Nb, Mo, W, Ti(/sub 5/Si₃, silicide in a W-free sample is 1680 GPa, and goes up to 1980 GPa in a W 15 mol.% sample. The hardness, however, of Nb solid solution does not exhibit a remarkable difference when the nominal W content is increased. The elastic modulus shows a similar tendency to the hardness. The optimum tensile properties of the composites investigated are achieved at W 5 mol.% sample, which exhibits a relatively good ultimate strength of 230 MPa and an excellent balance of yield strength of 215 MPa, and an elongation of 3.7%. The SEM fractography generally indicates a ductile fracture in the W-free sample, and a cleavage rupture in W-impregnated ones.

• Clinical Endoscopy
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• 제57권1호
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• pp.122-127
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• 2024

Benign biliary stricture (BBS) is a complication of chronic pancreatitis (CP). Despite endoscopic biliary stenting, some patients do not respond to treatment, and they experience recurrent cholangitis. We report two cases of CP with refractory BBS treated using endoscopic ultrasound-guided choledochoduodenostomy (EUS-CDS) fistula creation. A 50-year-old woman and a 60-year-old man both presented with obstructive jaundice secondary to BBS due to alcoholic CP. They underwent repeated placement of a fully covered self-expandable metal stent for biliary strictures. However, the strictures persisted, causing repeated episodes of cholangitis. Therefore, an EUS-CDS was performed. The stents were eventually removed and the patients became stent-free. These fistulas have remained patent without cholangitis for more than 2.5 years. Fistula creation using EUS-CDS is an effective treatment option for BBS.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 센서 박막재료 반도체재료 기술교육
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• pp.74-77
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• 2002

Ferroelectric Random Access Memory(FRAM) and MEMS applications require noble metal or refractory metal oxide electrodes. In this study, Ru thin films were etched using $O_2$+10% $CF_4$ plasma in an inductively coupled plasma(ICP) etching system. The etch rate of Ru thin films was examined as function of rf power, DC bias applied to the substrate. The enhanced etch rate can be obtained not only with increasing rf power and DC bias voltage, but also with small addition $CF_4$ gas. The selectivity of $SiO_2$ over Ru are 1.3. Radical densities of oxygen and fluorine in $CF_4/O_2$ plasma have been investigated by optical emission spectroscopy(OES). The etching profiles of Ru films with an photoresist pattern were measured by a field emission scanning electron microscope (FE-SEM). The additive gas increases the concentration of oxygen radicals, therefore increases the etch rate of the Ru thin films and enhances the etch slope. In $O_2$+10% $CF_4$ plasma, the etch rate of Ru thin films increases up to 10% $CF_4$ but decreases with increasing $CF_4$ mixing ratio.

• 한국분말재료학회지
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• 제22권3호
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• pp.187-196
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• 2015

With the stabilization of Korea's industrialization, it has become interested in the efficient use of rare metals, climate change and industrial environment and safety etc. It is thus making efforts to implement economic policies that address such issues. Therefore it is necessary to understand the demand, supply and use of metal materials. Since 2010, the Korean government has developed the integrated material flow methodology and has been trying to examine the demand, supply and use of metal materials. In 2013, the Korean government surveyed the material flow of chromium. Material flow analysis and environment emission of chromium were investigated 8 steps; (1) raw material, (2) first process, (3) Intermediate product, (4) End product, (5) Use/accumulation, (6) Collection, (7) Recycling, (8) Disposal. Chromium was used for stainless steel, alloy steel, coated sheets, refractory material and coating materials. Recycling was done mainly in use of stainless steel scrap. To ensure efficient use of chromium, process improvement is required to reduce the scrap in the intermediate product stage. In the process of producing of the products using chromium, it was confirmed that chromium was exposed to the environment. It requires more attention and protection against environment emission of chromium.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 추계학술대회 논문집 학회본부
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• pp.122-126
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• 1989

A composite polycide struoture consisting of refractory metal and noble metal silicide film on top of polysilicon bas been considered as a replacement for polysilicon as a gate electrode and Interconnect line in MOSFET integrated circuits. In this paper presents divice characteristics of NOS with $TiSi_2/n^+$polyoide and $CoSi_2/n^+$polycide gate. Also, evaporated Ti,Co films on polysilicon has been annealed by RTA and furnace annealing in $N_2$ abient at temperature of $400^{\circ}C-1000^{\circ}C$. The Ti-,Co-silioide formation is characterized by 4-point probe, silicide growth rate and Its reproductivity bas been examined by SEM.

• 한국산학기술학회논문지
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• 제15권8호
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• pp.4713-4716
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• 2014

알루미늄과 알루미늄 합금 제품의 고급화로 완벽한 알루미늄 용탕의 탈 가스 처리가 요구되고 있다. 탈 가스 처리를 위한 기존의 방법을 보면, 알루미늄 용탕 파우더와 약품 공급기로 이젝선하는 방법과 가스 취입 관을 사용하여 아르곤가스와 질소 또는 염소가스를 투입하는 방법 등이 사용되고 있다. 그러나 이 방법들은 작업도 어렵고, 염소와 불화물질 유해가스가 대단히 많이 발생하여 공해문제를 유발하는 문제점이 있으며 효과도 일정하지 않고, 과도한 처리시간으로 작업능률이 낮아지는 문제점도 있다. 가장 치명적인 문제점은 알루미늄 용탕과 약품의 반응으로 인한 많은 양의 찌꺼기의 생성과 더불어 금속의 손실 및 내화재의 수명감소를 야기하는 것이다. 이러한 문제점을 개선하기 위하여 본 연구에서는 기존에 알루미늄 연속제조를 위해 6단계 공정을 거처야 생산이 가능했던 부분을 이번에 개발한 3가지 공정만으로도 생산이 가능하게 알루미늄 연속 주조의 용탕과 탈 가스 장치의 일체화에 통한 기술을 개발에 관한 연구이다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 추계학술대회 논문집
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• pp.145-149
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• 2004

It is necessary for managing a perfect process for degasing aluminum molten metal according to the increase of a grade of aluminum and its alloy products. There are some methods that have been used to manage a degasing process in recent years, such as an injection method that uses aluminum molten metal powder and chemicals supplier and input method that supplies argon and nitrogen, or chlorine gas by using a gas blow-tube. However, these methods show some problems, and it shows that it is a difficult process to handle. pollution due to the producing a lot of toxic gases like chlorine and fluoride gas. irregular effects, and lowering work efficiency due to the excessive processing time. The problems that are the most fatal are the producing a lot of sludge due to the reaction of aluminum molten metal with chemicals. loss of metals, and decreasing the life of refractory materials. In order to solve these problems. this paper develops a technology that is related to aluminum continuous casting molten metal and monolithic degasing apparatus. A degasing apparatus developed in this study improved the exist ing methods and prevented environmental pollution wi th smokeless. odor less, and harmlessness by using a new method that applies argon and nitrogen gas in which the methods used in the West and Japan are eliminated. The developed method can significantly reduce product faults that are caused by the production of gas and oxidation because it uses a preprocessed molten metal with chemicals. In addition. the amount of the produced sludge can also be reduced by 60-80% maximum compared with the existing methods. Then. it makes it possible to minimize the loss of metals. Moreover. the molten metal processing and settling time is also shortened by comparing it with the existing methods that are applied by using chemicals. In addition, it does much to improve the workers' health, safety and environment because there is no pollution. The improvement of productivity and prevent ion effects of disaster from the results of the development can be summarized as follows. It will contribute to the process rationalization because it does not have any unnecessary processes that the molten metal will be moved to an agitator by using a ladle and returned to process for degasing like the existing process due to the monolithic configuration. There are no floating impurities due to the oxidation caused by the contact with the air as same as the existing process. In addition. it can protect the blending of precipitation impurities. Because it has a monolithic configuration. it can avoid the use of additional energy to compensate the temperature decreasing about 60t that is caused by the moving of molten metal. It is not necessary to invest an extra facilities in order to discharge the gas generated from a degasing process by using an agitator. The working environment can be improved by the hospitable air in the factory because the molten metal is almost not exposed in the interior of the area.