• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.235.1-235.1
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• 2014

Precise measurement of plasma parameters including density and temperature is the most essential part for understanding plasma characteristics. To persue more accurate measurement, it is very important to understand the intrinsic error of the measurement method. In this paper, we performed the plasma measurement with different method; langmuire probe and cutoff probe. Both measurement technology are known to be exactly correlate with etch other. We conducted the four set of same experiments process by diffrent persons to observe the intrinsic error based on measurement tools. As a result, the cutoff probe is relatively reliable then the Langmuir probe. This difference is analyzed to be intrinsic since it cames from the inevitable error such as manufacturing of probe tip. From this study, we sure that it is good decision to choose cutoff probe as repeatable measurement independent with intrinsic human factor.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.11
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• pp.508-511
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• 2003

In this paper, electrical characteristics of inductively coupled plasma in an electrodeless fluorescent lamp were investigated using a Langmuir probe with a variation of argon gas pressure. The RF output was applied in the range of 5 ∼ 50 (W) at 13.56 (MHz). The internal plasma voltage of the chamber and the probe current were measured while varying the supply voltage to the Langmuir probe in the range of -100 (V) ∼+100 (V). When the pressure of argon gas was increased, electric current was decreased. There was a significant electric current increase from l0W to 30 〔W〕. Also, when the RF power was increased, electron density was increase. This implies that this method can be used to find an optimal RF rower for efficient light illumination in an electrodeless fluorescent lamp.

• Journal of Astronomy and Space Sciences
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• v.12 no.2
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• pp.234-243
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• 1995

Korea's third rocket, which is currently under development for launch in 1997, is expected to reach as high as 160km and thus, it will provide a good opportunity for the direct measurement of the plasmas in the E-region ionosphere of the Korean peninsula. Langmuir probe techniques, which are the basic tools of the plasma experiment, may yield inaccurate results if they are applied in the conventional form as they are used in the laboratory experiments because of the contamination. In the present paper we study the contamination problem by performing the ground experiments in the vacuum chamber using the contaminated probe. The result show that the contamination effect is reduced when the plasma density is low or when the frequency of the sweep voltage is fast. We propose a modified Langmuir probe based upon our experiments which is suitable for the rocket experiments.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.1
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• pp.50-54
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• 2006

The study on discharge of the flat lamp lighting source has been requested increasingly. To improve the brightness, life time and efficiency of flat lamp, the plasma diagnosis of flat lamp lighting source is very important. When a distance of discharge electrode is 5.5mm and width is 16.5mm, we measured electron temperature and electron density with single Langmuir probe in flat lamp. Pressure conditions to test the plasma discharge from 100 Torr to 300 Torr. The power supply was PDS-4000 with frequency 20kHz and duty ratio $20\%.$ Form these experimental results, electron temperature was decreased according to increase the gas pressure and the voltage while electron density was increased.

• Proceedings of the KIEE Conference
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• 2004.11a
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• pp.150-152
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• 2004

In recent, there have been several developments in lamp technology that promise savings in electrical power consumption and improved quality of the lighting space. The electrodeless fluorescent lamp is intended as a high efficacy replacement for the incandescent reflector lamp in many applications. In this paper, electron temperature and electron density were measured in a radio-frequency inductively coupled plasma using a Langmuir probe method for emission characteristics. Measurement was conducted in an Ne discharge for pressure from 10 [mTorr] and input RF power 100 [W] to 150 [W]. As for the electron density, a electron temperature was more distinguished for a emission characteristic. The results of ideal may contribute to systematic understanding of a electrodeless fluorescent lamps of emission characteristics.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.433-433
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• 2010

A microplasma current switch (MPCS) for a device operated in a current mode like organic light-emitting diodes (OLEDs), which features matrix addressability and current switching, is presented as well as its architecture and operational principle. The MPCS utilizes the intrinsic memory and conductivity of plasmas to achieve matrix addressability and current switching. We have fabricated a $100\;mm\;{\times}\;100\;mm$ MPCS panel in which its cell pitch is $1080\;{\mu}m\;{\times}\;1080\;{\mu}m$. The matrix addressability and current switching were verified. In addition, the current-voltage (I-V) characteristic of the unit cell was measured when plasmas were ignited. In principle, the scheme of the MPCS is equivalent to that of a double Langmuir probe diagnosing plasma parameters except for their relative dimensions to a plasma volume. Accordingly, the I-V characteristic was analyzed by a double Langmuir probe theory, and the plasma density and electron temperature were estimated from the I-V curve using a collisional double Langmuir probe theory.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.158.1-158.1
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• 2013

Microwave는 일반적으로 300 [MHz]~30 [GHz] 사이의 주파수를 가지는 전파로 1 [m] 이하의 파장을 가진다. Microwave를 이용한 플라즈마의 경우 낮은 이온 에너지, 효율적인 전자 가열, 넓은 동작압력 범위, 높은 밀도 등의 장점을 가지고 있어 PECVD(Plasma Enhanced Chemical Vapor Deposition)에 적합한 플라즈마 소스라고 할 수 있다. 또한 Microwave는 파장의 길이가 증착이 이루어지는 진공 챔버의 길이보다 매우 작기 때문에 대면적 적용성이 용이하므로 현재 많은 연구가 이루어지고 있다. 본 연구에서는 Fluid Simulation을 통해 Maxwell's equation, continuity equation, electromagnetic wave equation 등을 이용하여 Microwave의 파워 및 압력에 따른 플라즈마 parameter를 계산하고, 자체 제작한 Linear microwave plasma 장치에서 정전 탐침(Langmuir Probe)을 이용하여 플라즈마 Parameter를 측정하였다. 또한 Simulation 결과와 실험결과를 비교 분석하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05e
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• pp.89-91
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• 2003

In this paper, using a Langmuir probe Ar gas characteristic of electrodeless fluorescent lamp which used an inductively coupled plasma were investigated. The RF output changed into 5-50W in 13.56MHz. At this time internal plasma voltage of the chamber and probe current were measured while changing in -70V - +70V with a supply voltage by Langmuir probe. If pressure of Ar gas was increased, the electric current tended to decrease. Also, an electric current was increased according to an increase of a RF output.

• 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 Telematics and Electronics D
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• v.36D no.5
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• pp.29-35
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• 1999

Inductively coupled plsama etching of platinum thin film was studied using $O_2$ addition to $Cl_2$/Ar gas plasma. In this study, Pt etching mechanism was investigated with Ar/$Cl_2$ /$O_2$ gas plasma by using XPS and QMS. Ion current density was measured with Ar/$Cl_2$ /$O_2$ gas plasma by using single Langmuir probe. It was confirmed by using QMS and single Langmuir probe that Cl and Ar species rapidly decreased and ion current density was also decreased with increasing $O_2$ gas ratios. These results implied that the decrease of Pt etch rate is due to the decrease of reactive species ans ion current density with increasing $O_2$ gas mixing ratios. A maximum etch rate of 150nm/min and the oxide selectivity of 2.5 were obtained at Ar/$Cl_2$ /$O_2$ flow rate of 50 seem, RF power of 600 W, dc bias voltage of 125 V, and the total pressure of 10 mTorr.