• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.2
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• pp.150-159
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• 2016

This paper presents a study on the design optimization of a 5 kW plasma discharger for driving plasma reactor. The proposed study is composed of a high-frequency inverter based on the full-bridge circuit using soft switching techniques for high-frequency switching. The switching frequency in the operating region is the area of 130-200 kHz. By applying the LC resonance technique and a variable switching frequency, control technique is designed to be stable under changes in the load characteristics of the plasma reactor. This paper presents a quantitative analysis technique for design optimization. Experiments are performed according to load characteristic variations depending on the vacuum of the plasma reactor. This paper has verified the topology and design method for the 5 kW plasma discharger design.

• Journal of the Korean institute of surface engineering
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• v.29 no.6
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• pp.834-838
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• 1996

The diagnosis of the plasma in the facing targets sputtering system was performed in mixture gas of Ar 0.18-0.0 Pa, Xe 0.0-0.18 Pa and $O_2$ 0.02 Pa by using Langmiur's probe and the effect of plasma-damage to surface smoothness and magnetic characteristics of Ba ferrite films was clarified. The electron density $N_e$ and the electron temperature $T_e$ were evaluated at the center of the plasma and at the neighborhood of the anode ring. $T_e$ decreased and $N_e$ increased with increase of $P_{Xe}$ at the center of plasma. For the measurement at the neighborhood of the anode ring, $T_e$ was almost constant and $N_e$ took the minimum value at $P_{Xe}$ of 0.1 Pa, where Ba ferrite films with excellent c-axis orientation and magnetic characteristics were obtained. It was suggested that the restriction of the bombardment of recoiled particles as well as the suppress of plasma-damage were effective for obtaining good surface smoothness and excellent magnetic characteristics and it was useful for decreasing the crystallization temperature of Ba ferrite films.

• Transactions on Electrical and Electronic Materials
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• v.9 no.1
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• pp.1-5
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• 2008

ZnS is an attractive material for future optical and electrical devices since it has a direct and wide band gap to provide blue emission at room temperature. In this study, inductively coupled $BCl_3/Ar$ plasma was used to etch ZnS:Mn thin films. The maximum etch rate of 164.2 nm/min for ZnS:Mn was obtained at a $BCl_3(20)/Ar(80)$ gas mixing ratio, an rf power of 700 W, a dc bias voltage of -200V, a total gas flow of 20 sccm, and a chamber pressure of 1Pa. The etch behaviors of ZnS:Mn thin films under various plasma parameters showed that the ZnS:Mn were effectively removed by the chemically assisted physical etching mechanism. The surface reaction of the ZnS:Mn thin films was investigated by X-ray photoelectron spectroscopy. The XPS analysis revealed that Mn had detected on the surface ZnS:Mn etched in $BCl_3/Ar$ plasma.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1564-1567
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• 2005

Zinc oxide thin films were grown at the t emperature of $100^{\circ}C$ and $150^{\circ}C$ by means of plasma enhanced atomic layer deposition (PEALD) and conventional atomic layer deposition for applying to the transparent thin film transistor (TTFT). The growth rate of $1.9{\AA}/cycle$ with oxygen plasma is similar to that of film grown with water. While the sheet resistivity of ZnO grown with water is 1233 ohm/sq, that of film grown with oxygen plasma was too high to measure with 4 point probe and hall measurement system. The resistivity of the films grown with oxygen plasma estimated to be $10^6$ times larger than that of the films grown with water. The difference of electrical property between two films was caused by the O/Zn atomic ratio. We fabricated ZnO-TFT by means of ALD for the first time and the ZnO channel fabricated with water showed saturation mobility of $0.398cm^2/V{\cdot}s$ with bottom gate configuration.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.922-925
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• 2007

In the usual dry etching process for the TFT-LCD fabrication, it is hard to monitor the basic plasma parameters such as density and temperature. However, the basic parameters are easily monitored during the dry etching process. We have simultaneously measured the electric characteristics and basic plasma parameters of the dry etching chamber during the process, analyzed them to interpret plasma parameters. For the Ar plasma discharge case, we could obtain the density and temperature from the electric characteristics using a simple simple sheath model.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.127-128
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• 2009

CCP방식의 식각에 있어서 CF4/O2 Plasma Etch에 Ar을 첨가함으로써 Etch특성이 어떻게 변화하는지를 조사하였다. FE-SEM를 이용하여 Etch Profile를 측정하였다. 또한 Elipsometer와 Nanospec을 이용하여 Etch rate를 측정하였다. Ar의 비율이 전체의 47%정도를 차지하였을 때까지 Etch Profile이 향상되었다가 그이후로는 다시 감소하는 것을 볼 수 있었다. Ar을 첨가할수록 etch rate은 계속 향상되었다. Ar을 첨가하는 것은 물리적인 식각으로 반응하여 Etch rate의 향상과 적정량의 Ar을 첨가했을 때 Etch profile이 향상되는 결과를 얻었다.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.28A no.9
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• pp.715-720
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• 1991

The electromagnetic fields radiated from an aperture on a conducting plance covered with a moving uniaxial plasma layer are analyzed. From wave equations in moving plasma and free space region, their solutions are obtained and radiation fields are determined by applying proper boundary conditions in each region. For a particular case of isotropic plasma layer, our results correspond to well-known results.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1220-1224
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• 2007

The effects of plasma damages to the organic thin film transistor (OTFT) during the fabrication process are investigated; metal deposition process on the organic gate insulator by plasma sputtering mainly generates the process induced damages of bottom contact structured OTFTs. For this study, various deposition methods (thermal evaporation, plasma sputtering, and neutral beam based sputtering) and metals (gold and Indium-Tin Oxide) have been tested for their damage effects onto the Poly 4-vinylphenol(PVP) layer surface as an organic gate insulator. The surface damages are estimated by measuring surface energies and grain shapes of organic semiconductor on the gate insulator. Unlike thermal evaporation and neutral beam based sputtering, conventional plasma sputtering process induces serious damages onto the organic surface as increasing surface energy, decreasing grain sizes, and degrading TFT performance.

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

• Transactions on Electrical and Electronic Materials
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• v.13 no.3
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• pp.157-161
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• 2012

In this study, we investigated the etching characteristics of ITO thin films and the effects of inert gases added to $Cl_2/BCl_3$ inductivity coupled plasma. The maximum etch rate of ITO thin film was 130.0 nm/min upon the addition of Ar (6 sccm) to the $Cl_2/BCl_3$ (4:16 sccm) plasma, which was higher than that with He or $N_2$ added to the plasma. The ion bombardment by $Ar^+$ sputtering was due to the relatively low volatility of the by-products formed in the $Cl_2/BCl_3$ (4:16 sccm) plasma. The surface of the etched ITO thin film was characterized by x-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). From the XPS results, it is concluded that the proper addition of Ar and He to the $Cl_2/BCl_3$ plasma removes carbon and by-products from the surface of the etched ITO thin film.