• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.158.2-158.2
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• 2013

저온 플라즈마는 물리적인 연구로부터 사용되는 DC glow 방전에서 반도체 공정장비에 이르기까지 많은 분야에 사용되고 있다. 이러한 플라즈마 연구 및 응용은 기본적인 플라즈마 진단에 바탕을 두고 있다. 특히 플라즈마의 전자밀도, 전자온도, 플라즈마 Potential 등은 공정에 중요한 변수이다. 이러한 플라즈마 변수들을 측정하기 위해서 일반적으로 Langmuir probe를 많이 사용하고 있다. 최근에는 Cutoff probe에 대한 연구도 많이 진행되고 있다. 본 연구에서는 두 가지 탐침측정방법을 통해 플라즈마변수를 진단한다. 그리고 각각의 진단방법에 대한 장단점을 실증적으로 비교하고 검증하며, 그 결과에 따라 탐침의 구조를 개선한다. 또한, 전자에너지 분포함수(EEDF)도 S/W, H/W적으로 분석을 하였다.

• Journal of the Korean institute of surface engineering
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• v.32 no.3
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• pp.461-466
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• 1999

Diamond-like carbon(DLC) films were directly deposited onto germanium(Ge) witness pieces and lenses by a capacitively coupled 13.56 MHz RF glow discharge plasma with $CH_4$ gas. The characterizations of DLC films were measured using a Raman and FTIR spectrometer. The configuration of Raman and FTIR spectra had a traditional shape. The IR transmittance was measured using an IR spectrophotometer. The maximum values of the IR transmission of Ge with the DLC/Ge/DLC, DLC/Ge/BBAR (broad band antireflection), DLC/Ge, and BBAR/Ge structures are 98%, 93%, 64%, and 63.5%, respectively, which come up to the theoretical values. The uniform DLC films were obtained by a rotation of the cathode at certain conditions.

• Textile Coloration and Finishing
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• v.6 no.3
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• pp.27-36
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• 1994

In order to produce a water repellent surface on polyester fabric, samples were treated in the atmosphere of $CF_4$ glow discharge plasma. The samples used in the study were ployester fabric and poyester film. The purpose of film treatment is for the comparison of hydrophobicity with fabric sample at same treatment condition. Radio frequency(13.56MHz) generator was used as electric source and its in put power is 100 Watt. Water repellency was evaluated by contact angle measurement. Result obtained are as follows. 1) Fiber interstice of original fabric was ana lysed as 0.43$\mu$m, and this value was sufficiently ideal for making water repellent fabric. 2) The most favorable setting position of substrate was the center area between two electrodes. 3) Fabric contact angle was higher than film contact angle at same treatment condition, and its difference was more than 50${\circ}$. And it was incapalbe of fabric contact angle measurement when the film contact angle was less than 90${\circ}$. because the fabric is susceptible to absorption of water by the capillary effect. 4) Fabric contact angle can not revealed the precise defferences of surface hydrophobicity, however, the film contact angle showed the real hydrophobic nature. 5) It was not sufficient method to evaluate the hydrophobicity of fabric surface by merely measure of the water contact angle. 6) It showed high water repellent nature at 0.06 torr of $CF_4$ plasma gas pressure and duration of 45 seconds treatment, and it can not be anticipated more improved nature if the pressure and duration of treatment time were increased.

• Clean Technology
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• v.16 no.3
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• pp.191-197
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• 2010

Repair reaction of plasma damaged porous methyl doped SiOCH films was carried out with silylation agents dissolved in supercritical carbon dioxide ($scCO_2$) at various reaction time, pressure, and temperature. While a decrease in the characteristic bands at $3150{\sim}3560cm^{-1}$ was detectable, the difference of methyl peaks was not identified apparently in the FT-IR spectra. The surface hydrophobicity was rapidly recovered by the silylation. In order to induce effective repair in bulk phase, the wafer was heat treated before reaction under vacuum or ambient condition. The contact angle was slightly increased after the treatment and completely recovered after the subsequent silylation. Methyl groups were decreased after the plasma damage, but their recovery was not identified apparently from the FT-IR, spectroscopic ellipsometry, and secondary ion mass spectroscopy analyses. Furthermore, Ti evaporator was performed in a vacuum chamber to evaluate the pore sealing effect. The GDS analysis revealed that the open pores in the plasma damaged films were efficiently sealed with the silylation in $scCO_2$.

• Journal of the Korean Vacuum Society
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• v.13 no.4
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• pp.175-181
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• 2004

We investigated the stability of the DLC film coated on 304 stainless steel substrate by Radio frequency assisted chemical vapor deposition method. Fracture and spallation behaviour of the coating was observed during micro-tensile test of the fil $m_strate composite. As the tensile deformation progressed, the cracks of the film were observed in the perpendicular direction to the tensile axis. Further deformation resulted in the plastic deformation with $45^{\circ}$ slip bands on the substrate surface. Spallation of the film occurred with the plastic deformation, which was initiated at the cracks of the film and was aligned along the slip directions. We found that both the cracking and the spallation behaviors are strongly dependent on the pre-treatment condition, such as Ar plasma pre-treatment. The spallation of the film was considerably suppressed in an optimized condition of the substrate cleaning by Ar glow discharge. We observed the improved stability with increasing duration of Ar plasma pre-treatment.nt.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1609-1611
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• 2001

A large cross-section pulsed electron beam generator of cold cathode type has been developed for industrial applications, for example, waste water cleaning, flue gas cleaning, and pasteurization etc. The operational principle is based on the emission of secondary electrons from cold cathode when ions in the plasma hit the cathode, which are accelerated toward exit window by the gradient of an electric potential. The conventional electron beam generators need an electron scanning beam because the small cross section thermal electron emitter is used. The electron beam of large cross-section pulsed electron beam generator do not need to be scanned over target material because the beam cross section is large by 300$cm^2$. We have fabricated the large cross-sectional pulsed electron beam generator with the peak energy of 200keV and beam diameter of 200mm and obtained the large area electron beam in the air. The electron beam current has been investigated as a function of accelerating voltage, glow discharge current, helium pressure, distance from the exit window and radial distribution in front of the exit window.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.3
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• pp.383-388
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• 2011

The cold hollow cathode gas ion source is under development for multi aperture focused ion beam (FIB) system. In this paper, we describe the cold hollow cathode ion source design and the general ion source performance using Ar gas. The glow discharge characteristics and the ion beam current density at various operation conditions are investigated. This ion source can generate maximum ion beam current density of approximately 120 mA/$cm^2$ at ion beam potential of 10 kV. In order to effectively transport the energetic ions generated from the ion source to the multi-aperture focused ion beam(FIB) system, the einzel lens system for ion beam focusing is designed and evaluated. The ions ejected from the ion source can be forced to move near parallel to the beam axis by adjusting the potentials of the einzel lenses.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1350-1351
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• 2008

대기압 플라즈마를 발생시키는 것은 종래의 저기압 플라즈마를 발생시키는 것 보다 대단히 어렵다. 하지만, 대기압 플라즈마는 진공장치가 필요 없고, 제작방식이 비교적 간편하며 살균, 의료, 표면처리 등 다양한 응용이 가능해서 그 잠재력이 매우 크다. 본 연구에서는 유전체가 없는 두 전극사이에서 대기압 저온 마이크로 플라즈마를 발생시켰으며, submicrosecond pulse 파형으로 glow discharge를 유지할 수 있었다. 플라즈마 소스의 전극 간격은 200[${\mu}m$]이고 방전개시전압은 약 450${\sim}$600[V]이다. 플라즈마를 발생시키기 위한 feeding gas는 He 100%이다. 본 연구에서 개발된 대기압 플라즈마는 소비전력이 2[W]미만으로 온도는 조건에 따라 40$^{\circ}C$미만으로 발생 가능하다. 또한 스펙트럼 분석 시 777nm인 산소원자의 peak이 다른 원자 혹은 분자들의 peak보다 월등히 높다.

• Journal of the Korean institute of surface engineering
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• v.44 no.5
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• pp.190-195
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• 2011

Diamond-like carbon (DLC) has many outstanding properties such as low friction, high wear resistance and corrosion resistance. However, it is difficult to achieve enough adhesion on the metal substrates because of weak bonding between DLC film and the metal substrate. The purpose of this study is to enhance an adhesion of DLC film. For improving adhesion, the substrate was treated by active screen plasma nitriding before DLC film deposing. Nitrided substrates were investigated by Glow Discharge Spectrometer (GDS), Micro-Vickers Hardness. DLC films were deposited on several metals by linear ion source, and characteristics of the films were investigated using nano-indentation, Field Emission Scanning Electron Microscope (FESEM). The adhesion was measured by scratch tester. The adhesion of DLC films was increased when nitriding layer was formed before DLC deposition. Therefore, the adhesion of DLC film can be enhanced as increasing the hardness of materials.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.2032-2034
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• 2000

The performance of ac plasma display panels (PDP) is influenced strongly by the surface glow discharge characteristics on the MgO thin films. This paper deals with the surface slew discharge characteristics and some physical properties of MgO thin films prepared by reactive RF planar unbalanced magnetron sputtering in connection with ac PDP. The samples prepared with the do bias voltage of -10V showed lower discharge voltage and lower erosion rate by ion bombardment than those samples prepared by conventional magnetron sputtering or E-beam evaporation. The main factor that improves the discharge characteristics by bias voltage is considered to be due to the morphology changes or crystal structure of the MgO thin film by ion bombardment during deposition process.