• Proceeding of EDISON Challenge
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• 2014.03a
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• pp.478-482
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• 2014

Graphene have renewed considerable interest in inorganic, two-dimensional materials for future electronics. However, graphene does not have a bandgap, it is limited to apply directly to transistors and logic devices. Hence, other layered materials such as molybdenum disulphide ($MoS_2$) have been investigated to address this challenge. Here, we find that the nature of contacts plays a more important role than the semiconductor itself. In order to understand the nature of $MoS_2$/metal contacts, we perform density functional theory electronic structure calculations based on linear combination of atomic for the geometry, bonding, binding energy, PDOS, LDOS and electronic structure. We choose Au as a contact metal because it is the most common contact metal. In this paper, we demonstrate $MoS_2$/Au contacts have a more promising potential in flexible nanoelectronics than $MoS_2$ itself.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.141-143
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• 1994

In this paper, an electrostatic micro-actuator is fabricated using flat p+ diaphragm. To avoid the buckling of the flat p+ diaphragm, the processes are designed appropriately. The fabrication processes of the actuator are the anisotropic etching with EPW, the boron diffusion process, Al deposition and the silicon to glass bonding using the negative photoresist. The distance between the p+ and Al electrodes is $10{\mu}m$, and the thickness of the p+ diaphragm is $2{\mu}m$. The measurement of the characteristic of the actuator is performed at 50V. The center displacement of the diaphragm is $1.5{\mu}m$ at 10Hz. In comparison with the experimental data of the actuator with corrugated diaphragm, it is confirmed that the actuator with flat diaphragm is more effective than that with corrugated one in the small deflection region.

• Macromolecular Research
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• v.10 no.1
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• pp.24-33
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• 2002

Interfacial and microfailure properties of carbon fiber/epoxy composites were evaluated using both tensile fragmentation and compressive Broutman tests. A monomeric and two polymeric coupling agents were applied via the electrodeposition (ED) and the dipping applications. A monomeric and a polymeric coupling agent showed significant and comparable improvements in interfacial shear strength (IFSS) compared to the untreated case under both tensile and compressive tests. Typical microfailure modes including cone-shaped fiber break, matrix cracking, and partial interlayer failure were observed under tension, whereas the diagonal slipped failure at both ends of the fractured fiber appeared under compression. Adsorption and shear displacement mechanisms at the interface were described in terms of electrical attraction and primary and secondary bonding forces.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.597-598
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• 2006

This paper describes a development of a new $1.4{\times}1.1$ and $2.0{\times}1.4mm$ RF SAW filters made by PCB substrate instead of HTCC package, and this technology can reduce the cost of materials down to 40%. We have investigated the multi-layered PCB substrate structures and raw materials to find out the optimal flip-bonding condition between the $LiTaO_3$ wafer and PCB substrates. Also the optimal materials and processing conditions of epoxy laminating film were found out through the experiments which can reduce the bending moment caused by the difference of the thermal expansion between the PCB substrate and laminating film. The new PCB SAW filter shows good electrical and reliability performances with respect to the present SAW filters.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.3075-3077
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• 2000

이동통신단말기 등의 표시소자로 사용되는 LCD(Liquid Crystal Diode)나 LED(Light Emitting Diode)의 표현의 한계를 극복하고 보다 많은 정보를 표시할 수 있는 가상의 화면을 구성하기 위한 400dpi급 LED array 칩과 이를 구동하기 위한 driver 칩을 패키징하는 방법에 대하여 연구하였다. 연성 인쇄회로기판(flexible Printed Circuit) 기판 위에 칩을 실장하여 제품의 소형화와 경량화 그리고 전선을 대체하여 신뢰성을 높일 수 있도록 설계하였고 알루미늄 wire bonding법으로 각각의 칩을 연결하는데 있어 고려해야할 패키지의 조건에 대하여 연구하였다. 본 연구의 목적은 휴대용 이동통신단말기의 경박단 소화를 위한 패키징 기술을 확보하는데 있다.

• Proceedings of the IEEK Conference
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• 2002.06a
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• pp.439-442
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• 2002

We present in this Paper a microwave Power sensor fabricated by a standard CMOS process and a bulk micromachining process. The sensor consists of a CPW transmission line, a resistor as a healer, and thermocouple arrays. An input microwave heater, the resistor so that the temperature rises proportionally to the microwave power and tile thermocouple arrays convert it to an electrical signal. The sensor uses air bridged 8round of CPW realized by wire bonding to reduce tile device size and cost and to improve the thermal impedance. Al/poly-Si junctions are used for the thermocouples. Poly-Si is used for tile resister and Aluminium is for transmission line. The resistor and hot junctions of the thermocouples are placed on a low stress silicon nitride diaphragm to minimize a thermal loss. The fabricated device operates properly from 1㎼ to 100㎽\ulcorner of input power. The sensitivity was measured to be ,3.2～4.7 V/W.

• Journal of IKEEE
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• v.19 no.2
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• pp.232-236
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• 2015

Super-junction trench MOSFET (SJ TMOSFET) devices are well known for lower specific on-resistance and high breakdown voltage (BV). For a conventional power MOSFET (metal-oxide semiconductor field-effect transistor) such as trench double-diffused MOSFET (TDMOSFET), there is a tradeoff relationship between specific on-state resistance and breakdown voltage. In order to overcome the tradeoff relationship, a SJ TMOSFET structure is suggested, but sensing the temperature distribution of TMOSFET is very important in the application since heat is generated in the junction area affecting TMOSFET. In this paper, analyzing the temperature characteristics for different number bonding for SJ TMOSFET with an embedded temperature sensor is carried out after designing the diode temperature sensor at the surface of SJ TMOSFET for the class of 100 V and 100 A for a BLDC motor.

• Proceedings of the KIEE Conference
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• 1987.07a
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• pp.279-283
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• 1987

In this paper an intelligent supervisory programmable controller for automatic assembly machine is developed. This is achieved by adding sequence control hardware with input-interrupts to supervisory real time language and also by incorporating an automatic planning method which uses a predicate logic model and an action model. The designed intelligent supervisory programmable controller is applied to Die Bonding Machine and is to found to work well.

• Proceedings of the KIEE Conference
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• summer
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• pp.1364-1366
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• 2004

When an underground pipeline runs parallel with DC-powered railways, it suffers from electrolytic corrosion caused by the stray current leaked from the railway negative returns. Perforation due to the electrolytic corrosion may bring about large-scale accidents even cathodically protected systems. Traditionally, bonding methods such as direct drainage, polarized drainage and forced drainage have been used in order to mitigate the damage on pipelines. In particular, the forced drainage method is widely adopted in Seoul. In this paper, we report the analysis of the stray current conditions in Seoul subway DC electrification system.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.3274-3275
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• 1999

This paper presents a new method of spacer assembly using anodic bonding method which is very simple and clean. The spacer having $100{\mu}m(W){\times}2.1{\mu}m(H)$ was bonded on amorphous silicon film of anode plate. Then, the vertical-type electrode was used for assembling of spacer in high voltage field emission display. In these results, we suggested that the vertical-type electrode provided spacer alignment for high aspect ratio and more simple batch process than conventional method.