• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.217-217
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• 2011

플라즈마를 이용하는 식각 및 증착등의 반도체공정에 있어서 최근에는 기판의 크기가 점차 증가하는 추세에 있다. 이러한 대면적 플라즈마 발생장치 내에서 플라즈마 밀도와 라디칼 농도의 공간적인 특성을 이해하는 것에 대한 중요성이 더해지고 있다. 이를 위해 Langmuir probe와 같은 전기적 접근법에 의한 진단방법이나 광학적 접근법에 의한 진단방법에 대한 연구가 이루어 졌다. 전기적 접근법에 의한 플라즈마의 진단방법은 원리가 간단하고 정확도가 높다는 장점이 있지만 진단 장치에 의한 플라즈마의 간섭이 크고 식각가스의 경우 진단이 어렵다는 단점이 있다. 그에 비해 광학적 진단방법은 플라즈마에 간섭이 많지 않은 방법으로 알려져 있고 레이저 형광법(LIF), 원적외선 레이저 흡수 분광법(IR laser Absorption Spectroscopy), 광량측정법(Actinometry)등이 있다. 이 중 레이저 형광법, 원적외선 레이저 흡수 분광법의 경우, 진단장치가 매우 복잡하고 가격이 비싸다는 단점을 가지고 있다. 반면 광량측정법의 경우 다른 광학적 접근법에 의한 진단방법에 비해 원리와 실험장치가 간단하고 공간적인 라디칼 분포의 진단이 쉽다는 점에서 장점을 가지고 있다. Actinometry는 Ar과 같은 불활성 기체를 작은 비율을 넣어서 여기 된 불활성 기체의 파장세기와 여기 된 측정 라디칼의 파장세기의 비교를 통해 상대밀도를 측정하는 방법이다. 이 측정 방법에 Abel's inversion equation을 적용함으로 해서 대면적 M-ICP(Magnetized - Induced Coupled Plasma)에서 식각가스인 $CF_4$플라즈마에서 F 라디칼 농도의 공간적인 분포를 측정하고 분석하였다. 또한 플라즈마의 압력, 소스 전력 값과 기판 전력 값등의 조건의 변화에 따라 F 라디칼 농도의 분포가 어떻게 달라지는지에 대해 측정 분석하여 다루었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전기물성,응용부문
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• pp.71-72
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• 2006

플라스틱 기판 위에 유도 결합 플라즈마 화학적 기상 증착장치 (Inductively Coupled Plasma Chemicai Vapor Deposition, ICP-CVD) 를 사용하여 실리콘 산화막 ($SiO_2$)을 증착하고, 엑시머레이저 어널링 (Excimer Laser Annealing, ELA) 과 $N_{2}O$ 플라즈마 전처리를 통해, 전기용량-전압(Capacitance-Voltage, C-V) 특성과 항복 전압장 (Breakdown Voltage Field) 과 같은 전기적 특성을 개선시켰다. 에너지 밀도 $250\;mJ/cm^2$ 의 엑시머 레이저 어닐링은 실리콘 산화막의 평탄 전압 (Flat Band Voltage) 을 0V에 가까이 이동시키고, 유효 산화 전하밀도 (Effective Oxide Charge Density)를 크게 감소시킨다. $N_{2}O$ 플라즈마 전처리를 통해 항복 전압장은 6MV/cm 에서 9 MV/cm 으로 향상된다. 엑시머 레이저 어닐링과 $N_{2}O$ 플라즈마 전처리를 통해 평탄 전압은 -9V 에서 -1.8V 로 향상되고, 유효 전하 밀도 (Effective Charge Density) 는 $400^{\circ}C$에서 TEOS 실리콘 산화막을 증착하는 경우의 유효 전하 밀도 수준까지 감소한다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.21-24
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• 2000

Ferroelectric YMnO$_3$ thin films are excellent dielectric materials for high integrated ferroelectric random access memory (FRAM) with metal-ferroelectric-silicon field effect transistor (MFSFET) structure. In this study, YMnO$_3$ thin films were etched with C1$_2$/Ar gas chemistries in inductively coupled plasma (ICP). The maximum etch rate of YMnO$_3$ thin films is 285 $\AA$/min under C1$_2$/Ar of 10/0, 600 W/-200 V and 15 mTorr. The selectivities of YMnO$_3$ over CeO$_2$ and $Y_2$O$_3$ are 2.85, 1.72, respectively. The results of x-ray photoelectron spectroscopy (XPS) reflect that Y is removed dominantly by chemical reaction between Y and Cl, while Mn is removed more effective by Ar ion bombardment than chemical reaction. The results of secondary ion mass spectrometer (SIMS) were equal to these of XPS. The etch profile of the etched YMnO$_3$ film is approximately 65$^{\circ}$and free of residues at the sidewall.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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• pp.1408-1409
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• 2006

In this paper, poly methyl methacrylate thin films were deposited on a ITO glass substrate using a plasma polymerization technique. In order to investigate the influence of the plasma coupling method and plasma conditions on the plasma polymerized poly methyl methacrylate (ppMMA) thin film properties, inductively coupled (ICP) and capacitively coupled plasma (CCP) were used to generate the plasma and the plasma parameters were varied. Molecular structures of the ppMMAs were investigated using a Fourier Transform Infrared (FT-IR) spectroscopy. Dielectric constants of the ppMMA thin films were investigated using a impedance analyzer (HP4192A, LF Impedance Analyzer). Current-Voltage (I-V) characteristics of the ppMMA thin films were investigated using a source measurement unit (SMU: Keithley 2400). Relationship between the plasma coupling technique/process parameter and ppMMA thin films properties were investigated.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 센서 박막재료 반도체 세라믹
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• pp.19-22
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• 2003

For use in constructing highly sensitive thermal detectors, the present authors have been studying the preparation of Superconducting Flux Flow Sensor(SFFS). In this research, SFFS with five channel ($5{\mu}m$/1channel) has been fabricated based on the flux flow using high temperature superconducting thin films by the ICP etching technique. We have designed a bolometer based on the temperature dependence of the kinetic inductance of a superconducting flux flow thin film. In this paper examines the fabrications and flux flow resistance and thermometer responses of the highly sensitive sensor constructed of a thin YBCO film. It is also suggested that they will be applicable to a new type of flux flow sensor.

• 자원환경지질
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• 제31권3호
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• pp.223-233
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• 1998

The environments in the vicinity of the Dalseong mine has been much contaminated by heavy metals related to CuW ore deposit, which is of hydrothermal pipe type mineralized by quartz monzonite in the andesitic rocks. Chalcopyrite and wolframite are major ore minerals and sphalerite, galena and others are associated. To investigate the contamination of heavy metals in plants, samples of plants and soils were analysed by ICP for Fe, Mn, Cu, Pb, Zn, Ni, Co, Cd and Cr. Most of ore-related heavy metals are anomalously high in plants and soils, which were contaminated by the development of Taehan Tungsten Mining Company. The mine produced 48,704 tons (M/T) of 4 wt.% Cu and 1,620 tons (S/T) of 70 wt.% of $WO_3$ during active mining activity from 1961 to 1971 but was closed in 1975. Wild plants growing at the mine area may be used to remove heavy metals form soils, which cause contaminations of plants, stream waters and groundwaters in the vicinity of the mine.

• Transactions on Electrical and Electronic Materials
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• 제14권2호
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• pp.67-70
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• 2013

In this study, we changed the input parameters (gas mixing ratio, RF power, DC bias voltage, and process pressure), and then monitored the effect on TiN etch rate and selectivity with $SiO_2$. When the RF power, DC-bias voltage, and process pressure were fixed at 700 W, - 150 V, and 15 mTorr, the etch rate of TiN increased with increasing $CF_4$ content from 0 to 20 % in $CF_4$/Ar plasma. The TiN etch rate reached maximum at 20% $CF_4$ addition. As RF power, DC bias voltage, and process pressure increased, all ranges of etch rates for TiN thin films showed increasing trends. The analysis of x-ray photoelectron spectroscopy (XPS) was carried out to investigate the chemical reactions between the surfaces of TiN and etch species. Based on experimental data, ion-assisted chemical etching was proposed as the main etch mechanism for TiN thin films in $CF_4$/Ar plasma.

• Korean Journal of Chemical Engineering
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• 제35권12호
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• pp.2452-2463
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• 2018

Surface treatment of sol-gel bioglass is required to increase its biomedical applications. In this study, a dielectric barrier discharge (DBD) plasma treatment in atmospheric pressure was performed on the surface of [$SiO_2-CaO-P_2O_5-B_2O_3$] sol-gel derived glass. The obtained bioglass was treated by plasma using discharge current 12 mA with an exposure period for 30 min. The type of discharge can be characterized by measuring the discharge current and applied potential waveform and the power dissipation. Apatite formation on the surface of the DBD-treated and untreated samples after soaking in simulated body fluid (SBF) at $37^{\circ}C$ is characterized by Fourier transform infrared spectroscopy (FTIR), X-Ray diffraction (XRD), inductively coupled plasma (ICP-OES) and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS). We observed a marked increase in the amount of apatite deposited on the surface of the treated plasma samples than those of the untreated ones, indicating that DBD plasma treatment is an efficient method and capable of modifying the surface of glass beside effectively transforming it into highly bioactive materials.

• Nuclear Engineering and Technology
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• 제54권5호
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• pp.1623-1634
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• 2022

A new irradiation loop design has been developed, which provides the ability to carry out radiolytic resistance studies of extraction systems simulating process relevant conditions in an easy and simple way. The step-by-step loop configuration permits an easy modification of settings and has a relative low volume requirement. This irradiation loop has been initially set up to test the main EURO-GANEX process steps: the lanthanide (Ln) and actinide (An) co-extraction followed by the transuranic (TRU) stripping. The performance and changes in the composition have been analyzed during the irradiation experiment by different techniques: gamma spectroscopy and ICP-MS for the extraction and corrosion behavior of the full system, and HPLC-MS and Raman spectroscopy to determine the degradation of the organic and aqueous solvents, respectively. The Ln and An co-extraction step and the corrosion that occurred during the first irradiation step revealed the favorable expected results according to literature. The effects of acidity changes occurred during the irradiation process, the presence of stainless corrosion products in solution as well as the new possible degradation compounds have been explored in the An stripping step. The results obtained demonstrate the importance of developing realistic irradiation experiments where different factors affecting the performance can be easily studied and isolated.

• 정보저장시스템학회논문집
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• 제1권1호
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• pp.93-98
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• 2005

Rewritable optical disk is one of the essential data storage media in these days, which takes advantage of the different optical properties in the amorphous and crystalline states of phase change materials. As well known, data transfer rate is one of the most important parameter of the phase change optical disks, which is mostly limited by the crystallization speed of recording media. Therefore, we doped Sn/Bi to $Ge_2Sb_2Te_5$ alloy in order to improve the crystallization speed and investigated the dependence of phase change characteristics on Sn/Bi doping concentration. The Sn/Bi doped $Ge_2Sb_2Te_5$ thin film was deposited by RF magnetron co-sputtering system and phase change characteristics were investigated by X-ray diffraction (XRD), static tester, UV-visible spectrophotometer, electron probe microanalysis (EPMA), inductively coupled plasma mass spectrometer (ICP-MS) and atomic force microscopy (AFM). Optimum doping concentration of Bi and Sn were 5${\~}$6 at.$\%$ and the minimum time for crystallization was below than 20 ns. This improvement is correlated with the simple crystalline structure of Sn/Bi doped $Ge_2Sb_2Te_5$ and the reduced activation barrier arising from Sn/Bi doping. The results indicate that Sn/Bi might play an important role in the transformation kinetics of phase change materials..