• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.429-429
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• 2012

To investigate the gettering effect of B-doped n-type monocrystalline silicon wafer, we made the p-n junction by diffusing boron into n-type monocrystalline Si substrate and then oxidized the boron doped n-type monocrystalline silicon wafer by in-situ wet and dry oxidation. After oxidation, the minority carrier lifetime was measured by using microwave photoconductance and the sheet resistance by 4-point probe, respectively. The junction depth was analyzed by Secondary Ion Mass Spectrometry (SIMS). Boron diffusion reduced the metal impurities in the bulk of silicon wafer and increased the minority carrier lifetime. In the case of wet oxidation, the sheet resistance value of ${\sim}46{\Omega}/{\Box}$ was obtained at $900^{\circ}C$, depostion time 50 min, and drive-in time 10 min. Uniformity was ~7% at $925^{\circ}C$, deposition time 30 min, and drive-in time 10 min. Finally, the minority carrier lifetime was shown to be increased from $3.3{\mu}s$ for bare wafer to $21.6{\mu}s$ for $900^{\circ}C$, deposition 40 min, and drive-in 10 min condition. In the case of dry oxidation, for the condition of 50 min deposition, 10 min drive-in, and O2 flow of 2000 SCCM, the minority carrier lifetime of 16.3us, the sheet resistance of ${\sim}48{\Omega}/{\Box}$, and uniformity of 2% were measured.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.250.2-250.2
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• 2015

결정질 태양전지의 변환효율은 이미 이론적 한계에 가까워져, 최근 산업에서는 이 대신 제조공정 단가를 낮추려는 연구가 진행되고 있다. 본 연구에서는 태양전지 도핑공정에 대기압 DBD 플라즈마를 응용하여 저렴하게 태양전지를 제작할 수 있는 방법을 모색한다. 대기압 DBD 플라즈마를 발생시키기 위해 DC-AC 인버터 구조의 전원을 사용하여 수십 kHz의 주파수, 수 kV의 전압을 인가하여 $5cm{\times}1cm$ 직사각형 모양의 아노다이징된 알루미늄 전극을 사용하였다. 전극과 Ground 사이에 Argon 가스를 주입하여 플라즈마를 발생시켰으며, 출력전류는 수십 mA의 전류가 측정되었다. $3cm{\times}3cm$의 P-type wafer에 스핀코팅 방식으로 H3PO4를 도포한 후, Wafer 표면에 플라즈마를 조사하여 대기압 DBD 플라즈마를 이용한 태양전지 도핑 가능성을 확인하였다. 플라즈마 출력 전류와 플라즈마 조사시간을 변수로 도핑된 Wafer의 특성을 확인하였다. 도핑 프로파일은 SIMS (Secondary Ion Mass Spectrometry)를 통해 측정하였으며, 전기적인 특성은 4 point probe로 면저항을 측정하였다. 대기압 DBD 플라즈마를 이용해 도핑된 wafer에 전극을 형성하여, 같은 도펀트를 사용하여 Furnace로 열 확산법을 이용해 도핑 공정을 진행한 wafer와 변환효율(Conversion efficiency)을 측정하여, 대기압 플라즈마를 이용한 도핑 가능성을 확인하였다.

• 천문학회보
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• 제38권2호
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• pp.95.2-95.2
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• 2013

The Van Allen Probes were designed to study the Earth's radiation belts on various scales of space and time. The identical two spacecrafts going nearly eccentric orbits lap each other several times over the course of the mission and each probe carries five instrument suites to address the science objectives on the radiation belt. Since Van Allen Probes launched on August 30, 2012, the probes detecte several storm events up to now. To understand the particle acceleration and loss mechanism in the radiation belt, we first focus on the energetic electrons' dynamics detected by ECT (Energetic Particle, Composition, and Thermal Plasma Suite). ECT measures near-Earth space's radiation particles covering the full electron and ion spectra from ~ eV to 10's of MeV with sufficient energy resolution. In this paper, we present the preliminary results of the recent several storm events using electron data from ECT(MagEIS and REPT).

• Journal of Advanced Marine Engineering and Technology
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• 제28권6호
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• pp.922-930
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• 2004

An experimental investigation was performed to study on the generation of air bubble and air core with swirling flow in a horizontal cicular tube. To determine some characteristics of the flow, 2D PIV technique is employed for velocity measurement in water. The experimental rig is manufactured from an acryl tube. The test tube diameter of 80mm, and a length of 3000mm. The used algorithm is the gray leve cross-correlation method(Kimura et al. 1986). An Ar-ion laser is used and the light from the laser(500mW) passes through a probe to make two-dimensional light sheet. In order to make coded images of the tracer particles on one frame, an AOM(Acoustic-Optical Modulator) is used. The maximum axial velocities showed near the test tube wall at y/D =0.1 and y/D =0.9 along the test tube. The higher Reynolds number increase, the lower axial velocities are showed in the center of the test tube. The air bubbles are generated from Re =10,000 and developed into air core from the recirculating water pump rpm equal 30Hz. The pressure and temperature are measured across the test tube at X/D=3.33.

• 한국진공학회지
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• 제2권4호
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• pp.501-506
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• 1993

The spatial potential distribution of electron cyclotron resonance plasma is measured as a function of tehsubstrate DC bias by Langmuir probe method. It is observed that the substrate DC bias changes the slope of the plasma potential near the subsrate, resulting in changes in flux and energy of the impinging ions across plasma $_strate boundary along themagnetric field. The effect of the substrate DC bias on the low-temperature silicon homoepitaxy (below $560^{\circ}C$) is examine dby in situ reflection high energy electron diffraction (RHEED), cross-section transmission electron microscopy (XTEM),plan-view TEM and high resolution transmision electron microscopy(HRTEM). While the polycrystalline silicon layers are grow withnegative substrate biases, the single crystaline silicon layers are grown with negative substrate biases, the singel crystalline silicon layers are grown with positive substrate biases. As the substrate bias changes form negative to positive values, the growth rate decreases. It is concluded that the control of the ion energy during plasma deposition is very important in silicon epitaxy at low temperatures below $560^{\circ}C$ by UHV-ECRCVD.VD.

• 동의생리병리학회지
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• 제27권6호
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• pp.759-763
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• 2013

This experiment was performed to investigate whether 50% ethanol extracts of the combined-preparation of Longanae Arilus, Chrysanthemi Flos, Zizyphi Fructus and Ginseng Radix alba (CPE) has hypnotic effects and/or enhances pentobarbital-induced sleeping time. Locomotor activity was evaluated using a ambulometer of tilting-type. The sedative-hypnotic effects were evaluated by measuring the sleeping onset time and sleeping time in pentobarbital-treated mice 30 min. after oral administration of CPE and muscimol. The intracellular $Cl^-$ concentration of cerebellar granule cells was estimated using $Cl^-$ sensitive fluorescence probe N-(ethoxycarbonylmethyl)-6-methoxyquinolinium (MQAE). CPE (150 mg/kg) decreased the locomotor activity, but CPE itself did not induce sleep. However, CPE reduced sleeping onset and prolonged sleeping time induced by pentobarbital (42 mg/kg). In addition, CPE (2 ${\mu}g/ml$) and pentobarbital (2.5 ${\mu}M$) itself did not affect on the chloride influx in primary cultured cerebellar granule cells, but the combination of CPE and pentobarbital (2.5 ${\mu}M$) increased the chloride influx onto the cells. In conclusion, it is suggested that CPE might augment pentobarbital-induced sleep through the increase of chloride influx.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.2
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• pp.1176-1179
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• 2003

Low-Pressure inductively coupled RF discharge sources have important industrial applications mainly because they can provide a high-density electrodeless plasma source with low ion energy and low power loss. In an inductive discharge, the RF power is coupled to the plasma by an electromagnetic interaction with the current flowing in a coil. In this paper, the experiments have been focussed on the electric characteristic and carried out using a single Langmuir probe. The internal electric characteristics of inductively coupled Ar RF discharge at 13.56 [MHz] have been measured over a wide range of power at gas pressure ranging from $1{\sim}70$ [mTorr].

• 한국전기전자재료학회논문지
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• 제21권8호
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• pp.727-732
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• 2008

In this work, the etch characteristics of $VO_2$ thin films were investigated using inductively coupled plasma (ICP) of $Cl_2/Ar$ gas mixtures. To analyze the plasma characteristics, a quadrupole mass spectrometer (QMS), an optical emission spectroscopy (OES), and a Langmuir probe measuring system were used. The surface reaction of the $VO_2$ thin films was investigated using X-ray photoelectron spectroscopy (XPS). It was found that an increase in Ar fraction in the $Cl_2/Ar$ plasma at fixed gas pressure, input power, and bias power resulted in increasing $VO_2$ etch rate which reached a maximum value of 87.6 nm/min at 70-75 % Ar. It was confirmed that the etch rate of the $VO_2$ films was mainly controlled by the ion flux. On the basis of measuring results, we will discuss possible etching mechanism of $VO_2$ film in the $Cl_2/Ar$ plasma.

• 한국공작기계학회논문집
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• 제10권1호
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• pp.133-140
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• 2001

Recently, to assure the integrity of a structural components such as piping pressure vessels and thinning structure, Lamb wave inspection technique has been used in material evaluation. It is very important to select the optimal Lamb wave mode and to analyze the signal accurately because of its unique dispersion properties grnerating several modes within the speci-men. It this study, the feasibility of material evaluation applications using wavelet analysis of Lamb wave has been veir-fied experimentally. These results show as follows; 1)dispersion characteristic of each mode in dispersion curve is demon-strated that A0 mode propagating material surface is useful mode having the lest energy loss and not sensitive to surface condition. 2) it can be detected even the micro defect ($1\times2mm$) fabricated in ultrasonic probe flaw distance (290mm) to axis direction. 3) the wavelet transform which is called "time-frequency analysis" shows the Lamb wave propagation due to the change of materials characterization can be evaluated at each frequency and experimental group velocity of Lamb wave agrees quite well with that of simulated dispersion curve.ion curve.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 반도체 재료 센서 박막재료 전자세라믹스
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• pp.137-140
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• 2004

We treated $O_2$ plasma on ITO thin film using RIE (Reactive Ion Etching) system, and analyzed the ingredient of ITO thin film according to change of processing conditions. The ingredient analysis of ITO thin film was used by EDS (Energy Dispersive Spectroscopy) and XPS (X-ray Photoelectron Spectroscopy) to compare and analyze the ingredient of bulk and surface. We measured electrical resistivity using Four-Point-Probe and calculated sheet resistance, and ITO surface roughness was measured by using AFM (Atomic Force Microscope). Finally, we fabricated OLEDs (Organic Light-Emitting Diodes) device using substrate that was treated optimum ITO surface. The result of the study for electrical and optical properties using I V L System (Flat Panel Display Analysis System), we confirmed that electrical properties (I-V) and optical properties (L-V) were improved.