• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.7
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• pp.522-526
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• 1998

We have fabricated a LDD structured polysilicon thin film transistor with low leakge current and the optimized LDD length has been obtained. The device performance is improved is improved by hydrogen passivation process. The on.off current ratio of poly0Si TFT s with $0.5{\mu}m$ and $1.0{\mu}m$ LDD length is much higher than that of conventional structured device due to the decrease of leakege current. The optimized LDD length may be $0.5{\mu}$ from the experimental data such as on/off current ratio, threshold voltage and hydrogenation effect.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.383-386
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• 1998

After etching Al-Cu alloy films using SiC1$_4$/Cl$_2$/He/CHF$_3$ plasma, a corrosion phenomenon on the metal surface has been studied with XPS (X-ray photoelectron spectroscopy) and SEM (Scanning electron microscopy). In Al-Cu alloy system, the corrosion occurs rapidly on the etched surface by residual chlorine atoms. To prevent the corrosion, CHF$_3$ plasma treatment subsequent to the etched has been carried out. A passivation layer is formed by fluorine-related compounds on the etched Al-Cu surface after CHF$_3$ and SF$_{6}$ treatment, and the layer supresses effectively the corrosion on the surface as the CHF$_3$ and SF$_{6}$ treatment pressure increases. The corrosion could be suppressed successfully with CHF$_3$ and SF6 treatment in the pressure of 300mTorr.orr.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.583-586
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• 2000

The non-selective method by polishing after grinding was used widely to thinning of SDB SOI structures. This method was very difficult to thickness control of thin film, and it was dependent on equipments. However electrochemical etch-stop, one of the selective methods, was able to accurately thickness control and etch equipment was very simple. Therefore, this paper described with the effect of leakage current and electrodes on electrochemical etch-stop. Consequentially, PP(passivation potential) was changed according to the kinds of contact and contact sizes, but OCP(open current potential) was not change with range of -1.5~-1.3V

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.397-400
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• 1997

This paper presentes the characteristics of Si anisotropic etching and electrochemical etch-stop in aqueous TMAH/IPA/pyrazine solution. (100) Si etching rate of 0.747 $\mu\textrm{m}$/min which faster 86% than TMAH 25 wt.%/IPA 17 vol.% solution was obtained using best etching condition at TMAH 25 wt.%/IPA 17 vol.%/pyrazine 0.1 g and the etching rate of (100) Si was decreased with more additive quantity of pyrazine. I-V curve of p-type Si in TMAH/IPA/pyrazine was obtained. OCP(Open Circuit Potential) and PP(Passivation Potential) were -2 V and -0.9 V, respectively. Si diaphragms were obtained by electrochemical etch-stop in aqueous TMAH/IPA/pyrazine solution.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05c
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• pp.83-87
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• 2003

Thin films of amorphous carbon (a-C) generally combine high wear resistance with low friction coefficients and a-C films have widespread applications as protective coatings and passivation of electrical circuit and insulating layer. In this work we deposited the amorphous carbon (a-C) films on silicon substrate with a high rate DC magnetron sputtering system. It is obtained parameters on the deposition rate and physical properties of a-C films using a wide range of Ar gas pressure and DC power. The physical properties of the films were analyzed by Nanoindenter and AFM (Atomic Force Microscopy), The electrical properties were investigated by electrical conductivity measurement.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.4
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• pp.255-262
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• 2020

Grain boundaries play a major role in determining device performance, particularly of polysilicon-based photodetectors. Through the post-annealing of as-deposited polysilicon and then, the analysis of electric behavior for a metal-polysilicon-metal (MSM) photodetector, we were able to identify the influence of grain boundaries. A modified model of polysilicon grain boundaries in the MSM structure is presented, which uses a crystalline-interfacial layer-SiO_x layer- interfacial layer-crystalline system that is similar to the Si-SiO₂ system in MOS device. Hydrogen passivation was achieved through a hydrogen ion implantation process and was used to passivate the defects at both interfacial layers. The thin SiO_x layer at the grain boundary can enhance the photosensitivity of an MSM photodetector by decreasing the dark current and increasing the light absorption.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.362-365
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• 1999

This paper describes on thinning SDB SOI substrates by SDB technology and electrochemical etch-stop. The surface of the fabricated SDB SOI substrates is more uniform than that grinding or polishing by mechanical method, and this process is possible to accurate SOI thickness control. During Electrochemical etch-stop, leakage current versus voltage curves were measured for analysis of the open current potential (OCP) point and the passivation potential (PP) poin and determinated to anodic substrates were analyzed by using AFM and SEM, respectivelv.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.6
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• pp.440-444
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• 2011

We have analyzed electrical characteristics of spot light solar cell modules and have completed fabrication of spot light solar cell modules. Before we test modules, we have carried about UV test of hologram. As a result of test, we have obtained 165% efficiency of hologram film. the other hand, we obtained 75% efficiency of general films. After we have fabricated solar modules and carried about field test, spot light solar cell modules with hologram have been investigated 17.3 A of Isc and 155.4 W of power.

• Journal of the Korean Vacuum Society
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• v.4 no.S2
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• pp.156-162
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• 1995

For a stimulating neural electrode, the charge density should be as large as possible to provide adequate stimulation of the nervous system while allowing for miniaturization of the electrode. Since iridium oxide is able to produce high charge densities while preventing undesirable reactions due to charge storage, it has become a promising material for neural prostheses. Successful production of stable Ir and Ir oxide films on various substrates now limits the use of this material. Ir was deposited on two differently prepared surface of (mirror finish, passivation) surgical Ti-6AI-4V with several methods. Ion beam mixing of sputter deposited Ir films on passivated Ti-6AI-4V produced stable and good adherent Ir films. It was found that the increase in charge density of pure Ir on continuous cyclingis due to the accumulation of the oxide phase ( associated with a large surface area) in which the valence state of iridium changes and the double-layer capacitance increases. This study also showed that the double layer capacitance is equally or even more responsible for the high charge density of anodically formed Ir oxide.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.34 no.4
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• pp.251-255
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• 2021

a-Si is commonly considered as a primary candidate for the formation of passivation layer in heterojunction (HIT) solar cells. However, there are some problems when using this material such as significant losses due to recombination and parasitic absorption. To reduce these problems, a wide bandgap material is needed. A wide bandgap has a positive influence on effective transmittance, reduction of the parasitic absorption, and prevention of unnecessary epitaxial growth. In this paper, the adoption of a-SiO_x:H as the intrinsic layer was discussed. To increase lifetime and conductivity, oxygen concentration control is crucial because it is correlated with the thickness, bonding defect, interface density (D_it), and band offset. A thick oxygen-rich layer causes the lifetime and the implied open-circuit voltage to drop. Furthermore the thicker the layer gets, the more free hydrogen atoms are etched in thin films, which worsens the passivation quality and the efficiency of solar cells. Previous studies revealed that the lifetime and the implied voltage decreased when the a-SiOx thickness went beyond around 9 nm. In addition to this, oxygen acted as a defect in the intrinsic layer. The D_it increased up to an oxygen rate on the order of 8%. Beyond 8%, the D_it was constant. By controlling the oxygen concentration properly and achieving a thin layer, high-efficiency HIT solar cells can be fabricated.