• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.400-400
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• 2007

In this study, we investigated liquid crystal (LC) alignment with ion beam (IB) that non contact alignment technique on polyimide and electro-optical characteristics of twisted nematic (TN)-liquid crystal display (LCD) on the polyimide under various ion beam angles. In this experiment, polyimide layer was coated on glass by spin-coating and Voltage-transmittance(VT) and response time characteristics of the TN cell were measured by a LCD evaluation system. The good characteristics of the nematic liquid crystal (NLC) alignment with the ion beam exposured polyimide surface was observed. In addition, it can be achieved the good EO properties, and residual DC property of the ion beam aligned TN cell on polyimide surface.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.10
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• pp.1517-1522
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• 2015

Since electric railroad vehicle pass through repeatedly on the railroad bridge, the dynamic load that causes the change of tension of contact wire affect it constantly. In this paper, we measured the dynamic displacement of the railroad bridges to analyze the effect of tension in the catenary. A result of dynamic measurement of the longitudinal displacement, it's maximum value was 39.9mm which was lower than the primary management criteria 378mm. Also on the based of a maximum temperature, it shows a feature that the longitudinal displacement value increased as temperature rise from April to October. In terms of behavior characteristics of a tensioning device, it was confirmed to be the value of 50mm stroke movement when the temperature changes ±5℃.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.11
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• pp.2214-2218
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• 2009

Dye-sensitized solar cell (DSC) has been considered as a possible alternative to current silicon based p-n junction photovoltaic devices due to its advantages of high efficiency, simple fabrication process and low production cost. Numerous researches for high efficient DSC in the various fields are under way even now. Among them, the compact layer, which prevents the back electron transfer between transparent conductive oxides and the redox electrolyte, is fabricated by various methods such as a ZnO dip-coating, $TiCl_4$ dip-coating, and Ti sputtering. In this study, we tried to fabricate the $TiO_2$ compact layer by the spin-coating method using aqueous $TiCl_4$ solution. The effect of the spin-coating method was checked as compared with conventional dip-coating method. As a result, DSC with a spin-coated compact layer had 33.4% and 6% better efficiency than standard DSC and DSC with a dip-coated compact layer.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.57 no.4
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• pp.408-411
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• 2008

As to this research is new structure of the semiconductor substrate heating apparatus. The fast thermoresponsive according to the direct heating structure of the heating plate layer adhering closely to the floor side of a substrate and the fast heat loss minimization can be accomplished. Moreover, the contact area of the sheath heater, which is the heating plate layer built-in heating apparatus, is increased, so that it has more heating valid area. For this, it adheres closely to the substrate, in which the photosensitive film is coated and the heating plate layer, adhering closely to the floor side of a substrate the mica layer which adheres closely to the floor side of the upper heating plate layer in order to minimize an insulation and heat loss, and the lower part of the mica layer and it is comprised of the floor plate layer. The heating plate layer forms the continued groove portion over the floor side whole. The sheath heater for heating a substrate is inserted with the groove portion and the heating plate layer is comprised. It is confirmed that by using the new substrate heating structure, the temperature change of the heating plate against the time is observed. Then, there is the electric power saving effect of about 40% in comparison with the existing method.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.239-242
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• 2004

We investigated the nanotopography impact on the post-chemical mechanical polishing (post-CMP) oxide thickness deviation(OTD) of ceria slurry with a surfactant. Not only the surfactant but also the slurry abrasive size influenced the nanotopography impact. The magnitude of the post-CMP OTD increased with adding the surfactant in the case of smaller abrasives, but it did not increase in the case of larger abrasives, while the magnitudes of the nanotopography heights are all similar. We created a one-dimensional numercal simulation of the nanotopography impact by taking account of the non-Prestonian behavior of the slurry, and good agreement with experiment results was obtained.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.280-283
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• 2004

This paper discribes the design concept, fabrication process and measuring result of 2.5kV Gate Commutated Thyristor devices. Integrated gate commutated thyristors(IGCTs) is the new power semiconductor device used for high power inverter, converter, static var compensator(SVC) etc. Most of the ordinary GTOs(gate turn-off thyristors) are designed as non-punch-through(NPT) concept; i.e. the electric field is reduced to zero within the N-base region. In this paper, we propose transparent anode structure for fast turn-off characteristics. And also, to reach high breakdown voltage, we used 2-stage bevel structure. Bevel angle is very important for high power devices, such as thyristor structure devices. For cathode topology, we designed 430 cathode fingers. Each finger has designed $200{\mu}m$ width and $2600{\mu}m$ length. The breakdown voltage between cathode and anode contact of this fabricated GCT device is 2,715V.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.42-43
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• 2005

본 연구에서는 Cu 슬러리에 부식방지제인 BTA를 첨가하여 슬러리내의 과수의 농도, pH 의 변화, 연마입자의 종류에 따라 연마거동에 미치는 영향과 각 chemical 변화에 따른 Cu surface의 변화를 살펴보았다. BTA (Benzotriazole, $C_6H_4C_3H$)를 첨가함으로써 본 연구에서 시행된 pH 와 과수의 변화에 상관없이 Cu-BTA film을 형성하여 Cu의 dissolution을 최대한 억제하는 것을 확인할 수 있었다. 또 그로인해 BTA를 첨가하지 않았을 때보다 얇은 passivation layer를 형성함을 알 수 있었고 contact angle도 더 높았다. 연마율의 경우에도 BTA가 첨가됨으로써 감소됨을 확인할 수 있었고 연마입자로 alumina particle을 사용한 경우에는 pH6, 과수 10vol%이상에서는 오히려 연마율이 증가하였다. fumed silica의 경우에는 hardness가 작아 mechanical적인 제거력이 낮아 BTA가 첨가되어도 연마율에는 큰 영향이 없었다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.15-16
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• 2005

Chalcogenide phase change memory has high performance to be next generation memory, because it is a nonvolatile memory processing high programming speed, low programming voltage, high sensing margin, low consumption and long cycle duration. We have developed a new material of PRAM with $Ge_1Se_1Te_2$. This material has been propose to solve the high energy consumption and high programming current. We have investigated the phase transition behaviors in function of various process factor including contact size, cell size, and annealing time. As a result, we have observed that programming voltage and writing current of $Ge_1Se_1Te_2$ are more improved than $Ge_2Sb_2Te_5$ material.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.167-168
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• 2006

High quality 3D-heterostructures were constructed by selective area (SA) molecular beam epitaxy (MBE) using a specially patterned GaAs (001) substrate. MBE growth parameters such as substrate temperature, V/III ratio, growth ratio, group V sources ($As_2$, $As_4$) were varied to calibrate the selective area growth conditions. Scanning micro-photoluminescence ($\mu$-PL) measurements and following analysis revealed that the gradually (adiabatically) coupled 2DEG-1D-1DEG field effect transistor (FET) system was realized. This 3D-heterostructure is very promising for the realization of the meso-scopic electronic devices and circuits since it makes it possible to form direct ohmic contact to the (quasi) 1DEG.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.119-120
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• 2007

반도체 공정에서 사용되는 ILD막질 중 oxy-nitrde(SiON) film은 contact etch stopper, photo공정을 위한 ARL(anti-reflection lay떠 그리고, 후속공정의 plasma damage에 대한 blocking layer로서의 역할을 담당하며 많은 공정에 널리 사용되고 있다. 그러나 막질 자체의 불완전성 (trap site, dangling bond)에 의해 cell current instability(CCI) 특성을 악화 시킬 수 있어 이에 대한 원인규명 및 대책이 요구되었다. 본 연구는 미국 S사(社) super flash memory에서 oxy-nitride 막질 증착 시의 gas flow량에 따른 CCI 특성변화를 연구하고 최적의 공정조건을 제시하고자 한다.