• Journal of the Semiconductor & Display Technology
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• v.12 no.1
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• pp.41-45
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• 2013

IGZO transparent conductive thin films were widely used as transparent electrode of optoelectronic devices. We have studied the optical and electrical properties of IGZO thin films. The IGZO thin films were deposited on the corning 1737 glass by RF magnetron sputtering method. The RF power in sputtering process was varied as 25, 50, 75and 100 W, respectively. All of the thin films transmittance in the visible range was above 85%. XRD analysis showed that amorphous structure of the thin films without any peak. The thin films were electrically characterized by high mobility above $13.4cm^2/V{\cdot}s$, $7.0{\times}10^{19}cm^{-3}$ high carrier concentration and $6{\times}10^{-3}{\Omega}-cm$ low resistivity. By the studies we found that IGZO transparent thin film can be used as transparent electrodes in electronic devices.

• Applied Science and Convergence Technology
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• v.27 no.1
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• pp.19-22
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• 2018

The ion energy and angle distributions (IEADs) in the DC magnetron sputtering systems are investigated for the variation of gas pressure using particle-in-cell simulation. Even for the condition of collisionless ion sheath at low pressure, it is possible to change the IEAD significantly with the change of gas pressure. The bombarding ions to the target with low energy and large incident angle are observed at low pressure when the sheath voltage drop is low. It is because the electron transport is hindered by the magnetic field at low pressure because of few collisions per electron gyromotion while the ions are not magnetized. Therefore, the space charge effect is the most dominant factor for the determination of IEADs in low-pressure magnetron sputtering discharges.

• Journal of the Korean Ceramic Society
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• v.37 no.6
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• pp.552-558
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• 2000

LiMn2O4 thin fiolm cathodes for Li-ion secondary battery were fabricated by r.f. magnetron sputtering technique. As-deposited films were amorphous. A spinel structure could not be obtained LiMn2O4 films by in-situ thermal annealing. After post thermal annealing over $700^{\circ}C$ in oxygen atmosphere, LiMn2O4 films prepared above 100 W r.f. power could be crystallized into a spinel structure. The electrochemical property of the LiMn2O4 film cathodes was tested in a Li/1 M LiClO4 in PC/LiMn2O4 cell. From cyclic voltammetry at scan rate of 2mV/sec of 2.5~4.5V, LiMn2O4 electrode prepared by post annealing at 75$0^{\circ}C$ showed good initial capacity. LiMn2O4 electrode prepared by post annealing at 80$0^{\circ}C$ showed the best crycling performance.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.04b
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• pp.204-208
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• 1995

Copper magnetron anode of a microwave-oven consists of an cylindrical outer-tube and various inner-vanes. The magnetron anode is produced by the complex process ; vane blanking, pipe cutting and sliver-alloy brazing of vanes. Recently, the backward extrusion process for forming vanes has been developed to avoid the complex procedures. The developed process is analyzed by using upper-bound elemental technique(UBET). In the UBET analysis, the upper-bound load, the configuration and the vane-height of final extruded product are determined by minimizing the total power consumption with respect to chosen parameters. To verify theoretical analysis, experiments have been carried out with pure plasticine billets at room temperature, using different web-thickness and number of vanes. The theoretical predictions both for forming load and vane-height are in reasonable agreement with the experimental results.

• Applied Science and Convergence Technology
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• v.27 no.2
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• pp.26-29
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• 2018

The ion energy and angle distributions (IEADs) in the DC magnetron sputtering systems are investigated for the variation of gas pressure using particle-in-cell simulation. Even for the condition of collisionless ion sheath at low pressure, it is possible to change the IEAD significantly with the change of gas pressure. The bombarding ions to the target with low energy and large incident angle are observed at low pressure when the sheath voltage drop is low. It is because the electron transport is hindered by the magnetic field at low pressure because of few collisions per electron gyromotion while the ions are not magnetized. Therefore, the space charge effect is the most dominant factor for the determination of IEADs in low-pressure magnetron sputtering discharges.

• Corrosion Science and Technology
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• v.5 no.1
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• pp.15-22
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• 2006

The introduction of two-grid inside a conventional process system produces a reactive coating deposition and increases metal ion ratio in the plasma, resulting in denser and smoother films. The corrosion behaviors of TiN coatings were investigated by electrochemical methods, such as potentiodynamic polarization test and electrochemical impedance spectroscopy (EIS) in deaerated 3.5% NaCl solution. Electrochemical tests were used to evaluate the effect of microstructure on the corrosion behavior of TiN coatings exposed to a corrosive environment. The crystal structure of the coatings was examined by X-ray diffractometry (XRD) and the microstructure of the coatings was investigated by scanning electron microscopy (SEM) and transmission electron spectroscopy (TEM). In the potentiodynamic polarization test and EIS measurement, the corrosion current density of TiN deposited by two grid-attached magnetron sputtering was lower than TiN deposited by conventional magnetron type and also presented higher Rct values during 240 h immersion time. It is attributed to the formation of a dense microstructure, which promotes the compactness of coatings and yields lower porosity.

• Journal of the Semiconductor & Display Technology
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• v.15 no.4
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• pp.36-40
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• 2016

The 2 wt.% Al-doped ZnO(AZO) thin films were fabricated on PET substrates with various RF power 20, 35, 50, 65, and 80W by using RF magnetron sputtering in order to investigate the structure, electrical and optical properties of AZO thin films in this study. The XRD measurements showed that AZO films exhibit c-axis orientation. At a RF power of 80W, the AZO films showed the highest (002) diffraction peak with a FWHM of 0.42. At a RF power of 65W, the lowest electrical resistivity was about $1.64{\times}[10]$ ^(-4) ${\Omega}-cm$ and the average transmittance of all films including substrates was over 80% in visible range. Good transparence and conducting properties were obtained due to RF power control. The obtained results indicate that it is acceptable for applications as transparent conductive electrodes.

• The Transactions of the Korean Institute of Power Electronics
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• v.22 no.5
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• pp.463-468
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• 2017

One of the most critical part for magnetron driving in microwave oven is start-up control. For this, switching frequency of resonant inverter should be carefully controlled in order to supply sufficient power to the filament of the magnetron and to prevent rectifier diode from destruction caused by the excessive voltage across them. This paper proposes a novel start-up control strategy for LLC resonant inverter for microwave oven considering the non-oscillation mode time and the magnetron voltage during the start-up process. The validity of the proposed method is verified through the experiment with 1,200W microwave oven using LLC resonant inverter.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.379-382
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• 1999

In this paper, we investigated the characteristics of MgO thin film prepared by unbalanced magnetron sputtering(UBMS) in surface discharge type AC PDP The minimum discharge voltage is obtained for the sample of substrate bias voltage-10V. Moreover the anti-sputtering characteristics of MgO thin film by UBMS is improved about 40% than one of balanced magnetron sputtering(BMS)

• Journal of the Semiconductor & Display Technology
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• v.15 no.3
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• pp.57-61
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• 2016

We have studied the structural, optical and electrical properties of IGZO thin films. The IGZO thin films were deposited on the silicon wafer by RF magnetron sputtering method. The RF power in sputtering process was varied as 15W, 30W, 45W, 60W, 75W, respectively. All of the thin films transmittance in the visible range was above 85%. XRD analysis showed that amorphous structure of the thin films without any peak. The Hall measurements in the low RF power is the high mobility above $10cm^2/V{\cdot}s$ and the low resistvity are obtained in the IGZO thin films.