• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2005.07a
• /
• pp.189-190
• /
• 2005

본 논문에서는 탄소나노튜브를 성장시키기 전 과정인 전처리시 촉매 층에 인가되는 마이크로웨이브 파워에 따른 탄소나노튜브의 성장 및 특성 변화를 관찰하였다. 촉매층으로 사용되는 Ni층과 adhesion층으로 사용되는 Ti층은 마그네트론 스퍼터링 방식으로 증착하였고, 탄소나노튜브 성장에는 마이크로웨이브 플라즈마 화학기상 증착기를 사용하였다 탄소나노튜브의 성장특성은 평면과 단면 SEM image를 통하여 관찰하였으며, Raman spectrometer 분석을 통하여 성장된 탄소나노튜브의 구조적 특성을 알아보았다.

• Journal of the Korean Chemical Society
• /
• v.36 no.2
• /
• pp.238-242
• /
• 1992

Traces of Chloride in aqueous solution was converted to volatile HCl or $Cl_2$ by acids to be analyzed by the moderate power (500W) Helium Microwave Induced Plasma. Optimum conditions were obtained and the detection limit was found to be 4.3 ppm which is about ten times more sensitive compared to the direct analysis of aqueous samples. In addition to the batch type, a continuous type analysis was studied as well.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.08a
• /
• pp.148-148
• /
• 2012

A cutoff probe is the novel diagnostic method to get the absolute plasma density with simple system and less assumption. However, high density of ion flux from plasma on probe tip can make the error of plasma density measurement because the dielectric material of probe tip can be damaged by ion flux. We proposed a shielded cutoff probe using the ceramic tube for protection from ion flux. The ceramic tube on probe tip can intercept the ion flux from plasma. The transmitted spectrum using the shielded cutoff probe is good agreement with E/M wave simulation result (CST Microwave Studio) and previous circuit simulation of cutoff probe [1]. From the analysis of the measured transmitted spectrum base on the circuit modeling, the parallel resonance frequency is same as the unshielded cutoff probe case. The obtained results of electron density is presented and discussed in wide range of experimental conditions, together with comparison result with previous cutoff method.

• Journal of the Korean Vacuum Society
• /
• v.9 no.1
• /
• pp.7-15
• /
• 2000

An ECR-PECVD system with the characteristics of high ionization rat다 ability of plasma processing in a wide pressure range and deposition at low temperature was manufactured and characterized for the deposition of thin films. The system consists of a vacuum chamber, sample stage, vacuum gauge, vacuum pump, gas injection part, vacuum sealing valve, ECR source and a control part. The control of system is carried out by the microprocessor and the ROM program. We have investigated the vacuum characteristics of ECR-PECVD system, and also have diagnosed the characteristics of ECR microwave plasma by using the Langmuir probe. From the data of system and plasma characterization, we could confirmed the stability of pressure in the vacuum chamber according to the variation of gas flow rate and the effect of ion bombardment by the negative DC self bias voltage. The plasma density was increased with the increase of gas flow rate and ECR power. On the other hand, it was decreased with the increase of horizontal radius and distance between ECR source and probe. The calculated plasma densities were in the range of 49.7\times10^{11}\sim3.7\times10^{12}\textrm{cm}^{-3}$. It is also expected that we can estimate the thickness uniformity of film fabricated by the ECR-PECVD system from the distribution of the plasma density.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.247.1-247.1
• /
• 2014

The capacitive coupled plasma is used widely in the semiconductor industries. Especially, the uniformity of the industrial plasma is heavily related with defect ratio of devices. Therefore, the industries need the capacitive coupled plasma source which can generate the uniform plasma and control the plasma's uniformity. To achieving the uniformity of the large area plasma, we designed multi-powered electrodes. We controlled the uniformity by controlling the power of each electrode. After this work, we started to research another concept of the plasma device. We make the plasma chamber that has multi-ground electrodes imaginary (CST microwave studio) and simulate the electric field. The shape of the multi-ground electrodes is ring type, and it is same as the shape of the multi-power electrodes that we researched before. The diameter of the side electrode's edge is 300mm. We assumed that the plasma uniformity is related with the impedance of ground electrodes. Therefore we simulated the imaginary chamber in three cases. First, we connected L (inductor) and C (capacitor) at the center of multi-ground electrodes. Second, we changed electric conductivity of multi-ground electrode. Third, we changed the insulator's thickness between the center ground electrode and the side ground electrode. The driving frequency is 2, 13.56 and 100 MHz. We switched our multi-powered electrode system to multi-ground electrode system. After switching, we measured the plasma uniformity after installing a variable vacuum capacitor at the ground line. We investigate the effect of ground electrodes' impedance to plasma uniformity.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.08a
• /
• pp.357-357
• /
• 2012

The doping process of the solar cell has been used by furnace or laser. But these equipment are so expensive as well as those need high maintenance costs and production costs. The atmospheric pressure plasma doping process can enable to the cost reduction. Moreover the atmospheric pressure plasma can do the selective doping, this means is that the atmospheric pressure plasma regulates the junction depth and doping concentration. In this study, we analysis the atmospheric pressure plasma doping compared to the conventional furnace doping. the single crystal silicon wafer doped with dopant forms a P-N junction by using the atmospheric pressure plasma. We use a P type wafer and it is doped by controlling the plasma process time and concentration of dopant and plasma intensity. We measure the wafer's doping concentration and depth by using Secondary Ion Mass Spectrometry (SIMS), and we use the Hall measurement because of investigating the carrier concentration and sheet resistance. We also analysis the composed element of the surface structure by using X-ray photoelectron spectroscopy (XPS), and we confirm the structure of the doped section by using Scanning electron microscope (SEM), we also generally grasp the carrier life time through using microwave detected photoconductive decay (u-PCD). As the result of experiment, we confirm that the electrical character of the atmospheric pressure plasma doping is similar with the electrical character of the conventional furnace doping.

• The Korean Journal of Ceramics
• /
• v.2 no.4
• /
• pp.212-215
• /
• 1996

This paper focuses the strength and wear resistance of CVD diamond films. The strength of free-standing CVD diamond films synthesized by microwave plasm CVD, DC plasma CVD, RF plasma CVD and arc discharge plasma jet CVD has been measured by three-point bending test. The wear resistance of CVD diamod films has been evaluated by the pin-on-disk type testing. diamond films coated on the base of sintered tungsten carbide pin by hot filament CVD have been rubbed with a sintered diamond disk in muddy water. Volume removed wear of CVD diamond has been compared with stellite, WC alloy and bearing steel.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2003.07a
• /
• pp.855-858
• /
• 2003

Carbon nanotubes (CNTs) were grown on Ni-coated TiN/Si substrate by microwave plasma chemical vapor deposition using mixture gas of $H_2/CH_4$ at low temperature of 500 $^{\circ}C$. Average diameter of CNTs could be easily controlled by $H_2$ plasma pretreatment time before CNTs growth. The turn-on voltages of CNT emitters were varied from 3.5 $V/{\mu}m$ to 9 $V/{\mu}m$ according to the hydrogen pretreatment conditions. The close relationship between electron emission characteristics and pretreatment time indicates that pretreatment condition can be a key process parameter in CNTs growth for field emission displays..

• ETRI Journal
• /
• v.17 no.2
• /
• pp.11-19
• /
• 1995

The plasma densities generated from a semiconductor bridge (SCB) device employing a capacitor discharge firing set have been measured by a novel diagnostic technique employing a microwave resonator probe. The spatial resolution of the probe is comparable to the separation between the two wires of the transmission lines (${\approx}$3 mm). This method is superior to Langmuir probes in this application because Langmuir probe measurements are affected by sheath effects, small bridge area, and unknown fraction of multiple ions. Measured electron densities are related to the land material and input energy. Although electron densities in the plasma generated by aluminum or tungsten-land SCB devices show a general tendency to increase steadily with power, at the higher energies, the electron densities generated from tungsten-land SCB devices are found to remain constant.

• Proceedings of the Korean Vacuum Society Conference
• /
• 1999.07a
• /
• pp.242-242
• /
• 1999

상대론적 전자빔 발생장치(300kV, 40kA, 60ns)를 통하여 발생하는 전자빔은 진공 중에서 공간전하한계전류값을 갖게 되어 진행이 어렵다. 이런 전자빔의 전파특성을 향상시키기 위하여 여러 가지 방법들이 실험되어졌다. 본 실험실에서 수행한 실험은 전자빔의 진행해나가는 도파관 속에 국부적인 plasma channel을 형성시키고 이에 따른 전자빔의 전파율의 향상을 유도하였다. 이때 형성되는 높은 에너지의 이온빔을 관찰하고 이온 전류밀도에 따른 전자빔의 수송효율사이의 관계를 관찰하였다. 전류밀도의 증가는 여러 가지로 응용 될 수 있다. 자유전자레이저(Free Electron Laser)는 microwave로부터 가시광선 영역을 포함해 X-ray 영역까지의 coherent radiation을 발생시킬 수 있는 개념의 장치이다. 이 장치에서 전자빔의 전류밀도는 출력되는 전자기파의 power와 직접적으로 관계하여 고출력 microwave 발생장치를 구성할 수 있다. 이번 실험에서는 일정한 국부적으로 형성된 plasma에 따른 강렬한 상대론적 전자빔의 전파효율의 향상을 관찰하였다.