• Transactions on Electrical and Electronic Materials
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• v.9 no.4
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• pp.169-172
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• 2008

We attempted to fabricate carbon nanotube field effect transistor (CNT-FET) using single walled carbon nanotube(SWNT) on the heavily doped Si substrate used as a bottom gate, source and drain electrode were fabricated bye-beam lithography on the 500 nm thick $SiO_2$ gate dielectric layer. We investigated electrical and physical properties of this CNT-FET using Scanning Probe Microscope(SPM) and conventional method based on tungsten probe tip technique. The gate length of CNT-FET was 600 nm and the diameter of identified SWNT was about 4 nm. We could observed gating effect and typical p-MOS property from the obtained $V_G-I_{DS}$ curve. The threshold voltage of CNT-FET is about -4.6V and transconductance is 47 nS. In the physical aspect, we could identified SWNT with phase mode of SPM which detecting phase shift by force gradient between cantilever tip and sample surface.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.11-11
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• 2004

나노기술은 크게 2가지 접근방법을 가진다. 하나는 위에서 아래로(Top-Down)라는 관점으로 벌크물질로부터 이온빔 등을 이용해 이를 작게 잘라가는 방식이며, 다른 하나는 아래에서 위로(Bottom-Up) 방식으로 재질을 구성하는 분자를 재구성해 원하는 물성 및 특성을 가지도록 만드는 방법이다. 이 두 가지 접근 방법은 원하는 결과를 얻기 위해 상호 보완적으로 사용되기도 한다. Top-Down방식의 대표적인 기기로는 접속이온빔 장치(FIB, Focused Ion Beam)를 등 수 있으며, Bottom-Up방식의 대표적인 기기로는 SPM(Scanning Probe Microscope)을 들 수 있다.(중략)

• Journal of the Korean institute of surface engineering
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• v.31 no.5
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• pp.261-265
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• 1998

We investigated compositional separation of Co-23%Cr magnetic alloy thin films with varying film thicknesses. Saturation magnetization and magnetic microstructures were investigated using vibrating sample magnetometer (VSM) and scanning probe microscope (SPM), respectively. Saturation magnetization was as 700 emu/cc for films below 50 nm-thick, and changed to 430 emu/cc for the ones above 2000 nm-thick. This may be due to increment of molar volume of Cr-enriched phase as film thickness increases. The surface grain size in AFM (atomic force microscope) measurement becomes larger as film thickness increases. The MFM (magnetic force microscope) reveals that magnetic microstructure is changed from the fine spherical domains to the maze type domains as film thickness increases. We conclude that employing thickness of Co-22%Cr films below 50 nm is favorable for high density recording in order to enhance perpendicular saturation magnetization and SNR (signal to noise ratio).

• Journal of Sensor Science and Technology
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• v.10 no.2
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• pp.125-133
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• 2001

Conducting polymer sensors show high sensitivity when exposed to volatile organic compounds gases at room temperature. The 8 sensor array using by polypyrrole and polyaniline has been fabricated by chemical polymerization for measuring sensing characteristics of VOCs gases. Conducting polymer was polymerized by using distilled pyrrole, aniline as a monomer and ammonium persulfate (APS) as an oxidant and dodecylbenzene sulfonic acid (DBSA) as a dopant. Dedoped film was synthesized by reverse voltage and redoped film was synthesized by using 1-octanesulfonic acid sodium salt as another dopant in electrochemical cell. The sensitivity and reversibility were influenced by doping, dedoping, redoping and thickness for the polypyrrole and polyaniline. We investigated the relation between the structure of conducting polymer and sensitivity of these sensors through the analysis of scanning electron microscope (SEM), scanning probe microscope (SPM) and $\alpha$-step.

• Tribology and Lubricants
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• v.20 no.2
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• pp.51-57
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• 2004

Micro/nano adhesion and friction properties of mixed self-assembled monolayer (SAM) with different chain length for MEMS application were experimentally studied. Many kinds of SAM having different spacer chains(C6, C10 and C18) and their mixtures (1:1) were deposited onto Si-wafer, where the deposited SAM resulted in the hydrophobic nature. The adhesion and friction properties between tip and SAM surfaces under nano scale applied load were measured using an atomic force microscope (AFM) and under micro scale applied load were measured using ball-on-flat type micro-tribotester. Surface roughness and water contact angles were measured with SPM (scanning probe microscope) and contact anglemeter. Results showed that water contact angles of mixed SAMs were similar to those of pure SAMs. The morphology of coating surface was roughened as mixing of SAM. Nano adhesion and nano friction decreased as increasing of the spacer chain length and mixing of SAM. Micro friction was decreased as increasing of the spacer chain length, but micro friction of mixed SAM showed the value between pure SAMs. Nano adhesion and friction mechanism of mixed SAM was proposed in a view of stiffness of spacer chain modified chemically and topographically.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2003.11a
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• pp.56-63
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• 2003

Micro/nano adhesion and friction properties of mixed self-assembled monolayer (SAM) with different chain length for MEMS application were experimentally studied. Many kinds of SAM having different spacer chains(C6, C10 and C18) and their mixtures (1:1) were deposited onto Si-wafer, where the deposited SAM resulted in the hydrophobic nature. The adhesion and friction properties between tip and SAM surfaces under nano scale applied load were measured using an atomic force microscope (AFM) and micro scale applied load were measured using ball-on-flat type micro-tribotester. Surface roughness and water wetting angles were measured with SPM (scanning probe microscope) and contact anglemeter. Results showed that wetting angles of mixed SAMs showed the similar value of pure SAMs. The coating surface morphology was increased as mixing of SAM. Nano adhesion and nano friction decreased as increasing of the spacer chain length and mixing of SAM. Micro friction was decreased as increasing of the spacer chain, but micro friction of mixed SAM showed the value between pure SAMs. Nano adhesion and friction mechanism of mixed SAM was proposed in a view of stiffness of spacer chain modified chemically and topographically.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.156-156
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• 2004

정보화 및 휴대화 시대에 있어서 폭증하는 정보량을 보다 작은 용기에, 보다 많이 그리고 보다 저렴하게 저장하기 위해서는, 기존 저장기기의 한계를 극복할 수 있는 새로운 개념의 차세대 정보 저장기기가 요구되어 진다. 나노미터 사이즈의 주사탐침이 기록매체표면에 근접하여 정보를 기록/재생하는 PSD는 상기한 저장기기의 대용량화, 소형화, 그리고 저가격화를 충족시킬 수 있는 신개념의 저장기기로, 그 기술적 근간을 SPM(Scanning Probe Microscope)기술과 MEMS(Micro Electro Mechanical Systems) 제작기술에 두고 있다.(중략)

• JSTS:Journal of Semiconductor Technology and Science
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• v.5 no.1
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• pp.24-29
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• 2005

Silicon nitride cantilevers integrated with silicon heaters and piezoelectric sensors were developed for the scanning probe microscope (SPM) based data storage application. These nitride cantilevers are expected to have better mechanical stability and uniformity of initial bending than the previously developed silicon cantilevers. Data bits of 40 nm in diameter were recorded on PMMA film and the sensitivity of the piezoelectric sensor was 0.615 fC/nm, meaning that indentations less than 20 nm in depth can be detected. For high speed operation, $128{\times}128$ cantilever array was developed.

• Journal of the Korean institute of surface engineering
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• v.32 no.6
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• pp.703-708
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• 1999

Silicides have been used extensively in ULSI logic device fabrication as contact materials for the active areas as well as the poly- Si gates. NiSi is a promising candidate for submicron device application due to less volume expansion, low formation temperature, little silicon consumption, and large stable processing temperature window. In this report, the microstructure of nickel silicides fabricated with a thermal evaporator has been investigated. We observed systematic transformation of Ni silicides of $Ni_2$Si, NiSi, $NiSi_2$, as annealing temperature increases. All the silicides have been identified by a X-ray diffractometer (XRD). The cross-sectional microstructure of silicides was examined by a transmission electron microscope (TEM) equipped with a energy dispersive spectrometer(EDS). The surface roughness of silicides was measured by scanning probe microscope(SPM). Although we observed thin oxide layer existed at the $Ni/NiSi_{x}$ interface, we fabricated successfully $550\AA$-thick planar Ni-monosilicide at the temperature range of$ 400~700^{\circ}C$.

• Polymer Science and Technology
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• v.15 no.3
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• pp.363-373
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• 2004

1980년대 초, IBM의 과학자들에 의해 양자역학 현상에 기초한 새로운 현미경이 발명되었다. 뾰족한 금속 팁에 전압을 걸고 전도성 시료의 표면에 접근시키면, 팁이 표면에 접촉하기 직전에 터널링에 의한 전류가 흐르게 된다. 이 전류는 거리에 매우 민감해서 고체 표면에 배열된 원자들에 의해 형성되는 표면 굴곡 (surface corrugation)이 분간 가능하였다. 이 기계가 바로 STM (Scanning Tunneling Microscope)이다 (그럼 1). 이 발명이 있기까지의 약 2세기 가량의 시간 동안 "누구에 의해서도 결코 감지된 적 없는" (H. J. Robinson, Physics Today, March, 24, 1984.) 원자와 분자는 과학자들의 논리 속에 이론상으로 존재할 뿐이었다. STM의 발명으로 인해 인류는 바야흐로 개개의 원자와 분자를 직접적으로 감지할 수 있게 되었던 것이다. 처음으로 STM을 이용하여 원자해상도로 본 표면은 실리콘의 안정한 표면인 Si (111)-7${\times}$7 표면이었는데, 이러한 실리콘 표면의 STM 사진의 예를 그림 2에 나타내었다. (중략)타내었다. (중략)