• Journal of the Korean Vacuum Society
• /
• v.7 no.3
• /
• pp.255-260
• /
• 1998

The ionized magnetron sputtering is very useful in filling of small metal contact or via in ULSI processing with very high ionization upto 80% based on incoming flux ratio. But fairly high sputtering gas pressure is required to get high ionization, which instead gives low deposition rate and diverse incoming neutral's angular distribution. The electron quenching by heavily sputtered metals and gas rarefaction were considered the main causes of decreased ionization in this process. RF pulsing of sputtering power was proposed to solve those two problems. The results showed that 10㎳/10 ㎳ and 100㎳/100 ㎳ of on/off pulsings were optimal pulse conditions from OES measurements and also XRD of deposited Ag film showed distinct change of (111) to (200) preferred orientation. These results were analysed in a view point of neutral gas heating and cooling by high power sputtering.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.29 no.2
• /
• pp.99-108
• /
• 2018

This paper presents a design study of a solid state power oscillator to replace the conventional magnetron. The operational conditions of a single-stage 300 W LDMOS power amplifier were fully characterized. The power module consisted of two amplifiers connected in parallel. A delay-line feedback loop was designed for self-oscillation. A phase shifter was inserted in the delay-line feedback loop for adjusting the round-trip phase. Experiments performed using the power oscillator showed an output power of 800 W and a DC-RF conversion efficiency of 58 % at 2.327 GHz. The measured results were in good agreement with those predicted by numerical simulations.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.21 no.5
• /
• pp.458-462
• /
• 2008

In this paper, we investigated the (002) preferred orientation and morphology characteristics of AlN thin film by using reactive rf sputtering. Additionally, AlN thin films grown in the range from 150 to 300 W were studied under room temperature without substrate heating and post annealing. Sputtered AlN thin films were well grown on Si substrates and the (002) main peak in XRD patterns showed the highest intensity at 300 W with $0.25^{\circ}$ degree of full width at half-maximum (FWHM). As increased RF power, the surface roughness was increased from 1.0 to 3.4 nm. In Fourier transformation infrared spectroscopy (FTIR), $A_1$ (TO) and $E_1$ (TO) mode closed to AlN thin film confirmed the changes with increasing the intensity rate. From these results, we could confirm a chance of the growth of AlN thin film by only low temperature.

• Journal of the Korean Vacuum Society
• /
• v.20 no.5
• /
• pp.322-326
• /
• 2011

Etch process of silicon dioxide layer by using capacitively coupled plasma (CCP) is currently being used to manufacture semiconductor devices with nano-scale feature size below 50 nm. In typical CCP plasma etcher system, plasmas are generated by applying the RF power on upper electrode and ion bombardment energy is controlled by applying RF power to the bottom electrode with the Si wafer. In this case, however, etch results often drift due to heating of the electrode during etching process. Therefore, controlling the temperature of the upper electrode is required to obtain improvement of etch repeatability. In this work, we report repeatability improvement during the silicon dioxide etching under extreme process conditions with very high RF power and close gap between upper and bottom electrodes. Under this severe etch condition, it is difficult to obtain reproducible oxide etch results due to drifts in etch rate, critical dimension, profile, and selectivity caused by unexpected problems in the upper electrode. It was found that reproducible etch results of silicon dioxide layer could be obtained by controlling temperature of the upper electrode. Methods of controlling the upper electrode and the correlation with etch repeatability will be discussed in detail.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.860-864
• /
• 2003

Recently. use of compound semiconductor is widely increasing in the area of LED and RF device. In this study, wafer bonding module is designed and optimized to bond 6 inches device wafer and carrier wafer. Bonding process is performed in vacuum environment and resin is used to bond two wafers. Load spreader and double heating mechanisms are adopted to minimize wafer warpage and void. Structure and heat transfer analyses show the designed mechanisms are very effective in performance improvement.

• Proceedings of the Korean Nuclear Society Conference
• /
• 1996.05d
• /
• pp.443-448
• /
• 1996

In this paper, the 100 % non-inductive current drive scenarios are addressed for the steady-state operation on KT-2 tokamak, with the profile control using fast wave and lower hybrid wave as the external tools. Considering the stability, the well-aligned current profiles with a reversed-shear and $q_{min}$ > 2.0 has been favor-able in high ${\beta}_{p}$ plasma, together with a possibly higher bootstrap current fraction. Therefore, the effects of the auxiliary heating power profile on the control of MHD favorable current profile are evaluated in detail.

• Radiation Oncology Journal
• /
• v.10 no.1
• /
• pp.1-6
• /
• 1992

The usefulness of hyperthermia for cancer therapy has been established. The purpose of the present investigation was to access feasibility of heating normal lung and the temperature and power requirement were compared with that for liver as solid organ in rabbits by using radiofrequent heating machine. In this study, 20 rabbits were divided into 2 groups according to the heating site and the method of temperature measurement; in group I : lung heating and temperature measuring in skin, esophagus and lung parenchyme; in group II : liver heating and temperature measuring in skin and liver parenchyme. The results were as follows; 1) When the maximum temperature was almost same in lung heating group and liver heating group, the power for liver heating was lesser required than the power for lung heating (p<0.05). 2) The temperature of esophagus for the measurement of mediastinum temperature was $1.1{\pm}0.9^{\circ}C$ higher than the temperature of lung parenchyme (p<0.05). Therefore the above findings suggest lung, air containing organ, is well heated as same as liver, solid organ. So more active trials of lung heating in the lung cancer must be likely considered. But when the lung is heated, the esophageal temperature is higher than lung parenchyme, so the mediastinum damage must be considered seriously.

• Proceedings of the Korean Vacuum Society Conference
• /
• 1999.07a
• /
• pp.208-208
• /
• 1999

It is found that with increasing power, the measured electron energy distribution by Langmuir probe evolves into a Druyvesteyn-like electron energy distribution in the low-pressure regime of 1mTorr in a small inductively coupled plasma. Electron bounce resonance is introduced to explain the transition of the electron energy distribution against the rf power, The energy diffusion coefficients which determine the shape of the electron energy distribution in elastic range are calculated with and without electron bounce resonance. This electron energy distribution transition is well explained by the electron bounce resonance.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2007.11a
• /
• pp.522-522
• /
• 2007

We observed new physical phenomia. The dispersion relation and the distributions of RF electric field in the corrugated wall waveguide are analyzed numerically. The measurement of the dispersion relation are obsered by a plunger method employed in the slow wave structure for linear accelerators.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.46 no.6
• /
• pp.50-57
• /
• 2009

In this paper, a deep-heating stimulation system and protocol were designed to substitute the heat effect of moxibustion. Moxibustion is used to increase immunity and cure disease. But, it is difficult to control power of heat stimulation. A designed deep-heating stimulation system using Radio-Frequency(RF) is easy to control power of heat stimulation. Also, the stimulation protocol for substitution of the heat effect of moxibustion is proposed. Core temperature was applied to infrared camera, thermometer, and infrared sensor, and then was compared with that of moxibustion. The proposed system showed that it is more effective than moxibustion in transferring heat effect in such a deep part. Also, it shows the possibility of usefulness of deep-heating stimulation system and heat stimulation protocol.