• E2M - 전기 전자와 첨단 소재
• /
• 제7권4호
• /
• pp.294-299
• /
• 1994

CHF$_{3}$/CH$_{4}$Ar 플라즈마에 의해 형성된 산화막 식각 잔류물의 화학구조와 이 잔류물의 제거를 위한 세정방법을 x-ray photoelectron spectroscopy를 이용하여 조사하였다. 잔류무르이 구조는 CF$_{x}$-polymer와 Si-C, Si-O 결합으로 이루어진 SiO$_{y}$ C$_{z}$ 이었다. CF$_{4}$O$_{2}$ 플라즈마에 의한 silicon light etch는 산화막 식각 잔류물인 SiO$_{y}$ C$_{z}$ 층과 손상된 실리콘 표면을 제거하엿으며 NH$_{4}$OH-H$_{2}$O$_{2}$과 HF용액으로 완전히 제거되는 CF$_{x}$-polymer/SiO$_{x}$층을 남겼다. 100.angs.정도의 silicon light etch는 minority carrier life time과 thermal wave signal값을 초기 웨이퍼 수준까지 회복시켰으며 접합누설 전류도 거의 습식 식각 공정수준까지 감소시켰다.

• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 2009년도 춘계학술대회 논문집
• /
• pp.160-161
• /
• 2009

마이크로웨이브 플라즈마 화학기상증착(MPCVD) 시스템을 이용하여 실리콘 웨이퍼 위에 나노결정질 다이아몬드 박막을 증착하였다. 공정압력, 마이크로웨이브 전력, Ar/$CH_4$ 조성비를 일정하게 놓고 기판온도를 $400^{\circ}C$ 및 $600^{\circ}C$, 증착시간을 0.5, 1, 4시간으로 변화시켜 박막의 성장 과정을 관찰하였다. 성장 초기에 약 30 nm 크기의 나노 결정립으로 이루어진 구형 입자가 형성되어 시간의 경과에 따라 입자들이 성장하고 4시간 이후에는 입자들이 서로 붙어 완전한 박막을 형성함을 관찰하였다. 같은 증착시간에서 기판온도가 $400^{\circ}C$에서 $600^{\circ}C$로 증가함에 따라 다이아몬드 입자의 크기가 증가하였다. 시간의 경과에 따라 기판 위에서 입자들이 차지하는 면적의 비율은 증가하였다.

• 한국분무공학회지
• /
• 제2권4호
• /
• pp.47-53
• /
• 1997

By using a premixed laminar burner, the effect of mixture component on laminar burning velocity($S_L$) was investigated. The following was made clear ; (1)As the humidity$(H_2O)$, $CO_2$ and Ar in mixture is increased, $S_L$ decreased in proportion to quantity of those dilution gases. (2) The heat reaction theory says that mean thermal conductivity $(\lambda_m)$, specific heat $(C_{pm})$ of mixture and adiabatic flame temperatures $(T_b)$ affect $S_L$. As a result of theoretical analysis, the effect of $\lambda_m\;and\;C_{pm}$ on $S_L$ is less than 1/25 of the effect of $T_b$, so the effect of $\lambda_m\;and\;C_{pm}$ can be ignored. (3) From experimental results, it was confirmed that $\ln(S_L)$ is proportional to $(1/T_b)$, that is, the effect of $H_2O$ on $S_L$ is mainly caused by changes of $T_b$. This conclusion was verified by the fact increases of $H_2O,\;CO_2$ and Ar decrease the intensity of radiation typical $C_2$, CH, and OH in the same manner.

• 한국표면공학회지
• /
• 제50권6호
• /
• pp.516-522
• /
• 2017

We report the growth of carbon nanotubes (CNT) on Invar-42 plates using coal tar pitch (CTP) by chemical vapor deposition (CVD) method. The solid phase CTP is used as an inexpensive carbon source since it produces a bunch of hydrocarbon gases such as $CH_4$ and other $C_xH_v$ by thermal decomposition over $450^{\circ}C$. The Invar-42 is a representative Ni-based ferrous alloy and can be used repetitively as a substrate for CNT growth because Ni and Fe are used as very active catalytic elements. We changed mixing ratio of carrier gases, argon and hydrogen, and temperature of growth region. It was found that the optimum gas ratio and temperature for high quality CNT growth are $Ar:H_2=400:400$ sccm and $1000^{\circ}C$, respectively. In addition, the carbon nanoball (CNB) was also obtained by just changing the mixing ratio to $Ar:H_2=100:600$ sccm. Finally, CTP can be employed as a versatile carbon source to produce various carbon-based nanomaterials, such as CNT and CNB.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
• /
• pp.233.2-233.2
• /
• 2016

Graphite의 순도, 결함, 결정층, 전기저항이 개선을 위하여, 10,000K 이상의 초고온 RF 열플라즈마 처리에 관한 연구를 수행하였다. 방전가스는 Ar을 사용하고, 특성 개선을 위하여 첨가가스로 $H_2$, $CH_4$을 첨가하여 흑연의 열플라즈마 처리에 의한 특성을 고찰하였다. Energy Dispersion Spectroscopy을 이용한 탄소 함량 분석 결과, 75wt% 저급 흑연에 함유된 유무기 불순물은 고온의 플라즈마에 의해 제거되어 99wt% 이상으로 순도가 개선되었고, XRD 및 Raman 분석으로부터 고온 열처리를 통한 탄소원자의 재배열로 흑연의 $sp^2$결함이 감소되고, 결정성이 향상됨을 확인하였다. 또한 열플라즈마로 처리된 흑연입자에 대한 분체저항 측정 결과, $10^{-3}{\Omega}{\cdot}cm$에서 $10{-4}{\Omega}{\cdot}cm$로 감소되었다.

• 한국연초학회지
• /
• 제21권1호
• /
• pp.49-56
• /
• 1999

Classification of esterase isozymes of the apterous green peach aphids (Myzus persicae Sulzer) collected in tobacco fields were investigated by the native polyacrylamide gel electrophoresis (PAGE). A total of twelve esterase bands were identified in adult apterous aphid, and the difference of enzyme band activity in the clones was observed at the first and second bands group. Esterases of green peach aphids reacted with specific substrate were more stained $\alpha$-naphthyl acetate than $\alpha$-naphthyl propionate, and $\alpha$-naphthyl acetate more than $\beta$-naphthyl acetate. Twelve esterases on the basis of inhibition by the three types of inhibitors (organophosphates: 2.5$\times$10$^{-3}$ M paraoxon, 4$\times$10$^{-3}$ M DFP; eserine sulfate : 2$\times$10$^{-3}$ M eserin; sulfhydryl reagents: 2$\times$10$^{-3}$ M p-HMB) were classified into three class, namely, cholinesterase (ChE) I, II, carboxylesterase (CE) and arylesterase (ArE), and these classes contained 3, 4, 3 and 2 isozymes, respectively.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
• /
• pp.169-169
• /
• 2008

To keep pace with scaling trends of CMOS technologies, high-k metal oxides are to be introduced. Due to their high permittivity, high-k materials can achieve the required capacitance with stacks of higher physical thickness to reduce the leakage current through the scaled gate oxide, which make it become much more promising materials to instead of $SiO_2$. As further studying on high-k, an understanding of the relation between the etch characteristics of high-k dielectric materials and plasma properties is required for the low damaged removal process to match standard processing procedure. There are some reports on the dry etching of different high-k materials in ICP and ECR plasma with various plasma parameters, such as different gas combinations ($Cl_2$, $Cl_2/BCl_3$, $Cl_2$/Ar, $SF_6$/Ar, and $CH_4/H_2$/Ar etc). Understanding of the complex behavior of particles at surfaces requires detailed knowledge of both macroscopic and microscopic processes that take place; also certain processes depend critically on temperature and gas pressure. The choice of $BCl_3$ as the chemically active gas results from the fact that it is widely used for the etching o the materials covered by the native oxides due to the effective extraction of oxygen in the form of $BCl_xO_y$ compounds. In this study, the surface reactions and the etch rate of $Al_2O_3$ films in $BCl_3/Cl_2$/Ar plasma were investigated in an inductively coupled plasma(ICP) reactor in terms of the gas mixing ratio, RF power, DC bias and chamber pressure. The variations of relative volume densities for the particles were measured with optical emission spectroscopy (OES). The surface imagination was measured by AFM and SEM. The chemical states of film was investigated using X-ray photoelectron spectroscopy (XPS), which confirmed the existence of nonvolatile etch byproducts.

• 한국전자통신학회논문지
• /
• 제8권4호
• /
• pp.549-554
• /
• 2013

CVD를 이용하여 Cu 시편에 그래핀의 합성을 보이고, Cu 시편의 grain 크기와 방향성에 따른 그래핀의 성장거동을 보이고자 한다. 동일한 온도 및 압력 하에서도 사용하는 분위기 가스의 종류에 따라서 Cu의 확산에 영향을 주게 되고, 그래핀 합성 시 사용되는 $H_2$와 $CH_4$ 가스 분위기 하에서 Cu grain의 성장에도 영향을 미치는 것을 알 수 있었으며, 결과적으로 Cu grain의 성장이 그래핀의 합성과 성장에 직접적인 관련이 있음을 보이고자 하였다. 부식 저항성은 상온에서 동전위 분극실험를 통하여 분석하였으며, 부식속도 비교에서 그래핀 코팅된 Cu 시편의 경우가 그래핀의 화학적 안정성에 기인하여 순수 Cu 시편의 경우보다 동일한 부식 환경에서 약 10배 정도 안정적인 것으로 관찰이 되었다. 또한, grain boundary를 포함, 결함이 없는 그래핀의 균일한 성장의 가능성을 보이고, 이의 합성을 통한 공학적인 활용이 그 최종적인 목적이 될 것이다.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
• /
• pp.644-644
• /
• 2013

Graphene is a two-dimensional sp2 layer material. Despite the short history in the empirical synthesis of the graphene layers, the academic/industrial unique features have brought highly significant interest in research and development related to graphene-related materials. In particular, the electrical and optical performances have been targeted towards pre-existing microelectronicand emerging nanoelectronic applications. The graphene synthesis relies on a variety of processing factors, such as temperature, pressure, and gas ratios involving H2, CH4, and Ar, in addition to the inherent selection of copper substrates. The current work places its emphasis on the role of experimental factors in growing graphene thin films. The thermally-grown graphene layers are characterized using physical/chemical analyses, i.e., four point resistance measurements, Raman spectroscopy, and UV-Visible spectrophotometry. Ultimately, an optimization strategy is proposed in growing high-quality graphene layers well-controlled through empirical factors.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1997년도 추계학술대회 논문집 학회본부
• /
• pp.276-278
• /
• 1997

The reliable etching process is one of the essential steps in fabricating GaN based-device. High etch rate is needed to obtain a deeply etched structure and perfect anisotropic etched facet is needed to obtain lasing profile. In the research, therefore, we had proposed a planar inductively coupled plasma etcher (Planar ICP Etcher) as a high density plasma source, and studied the etching mechanism using the $CH_4/H_2$/Ar gas mixture. Dry etching characteristics such as etch rate, anisotropic etching profile and so on, for the III-V nitride layers were investigated using Planar ICP Etcher, based on the plasma characteristic as a variation of plasma process parameters.