• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전기물성,응용부문
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• pp.101-102
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• 2006

PZT thin films, which are the representative ferroelectric materials in ferroelectric random access memory (FRAM), have some serious problem such as the imprint, retention and fatigue which ferroelectric properties are degraded by repetitive polarization. BL T thin film capacitors were fabricated by plasma etching, however, the plasma etching of BLT thin film was known to be very difficult. In our previous study, the ferroelectric materials such as PZT and BLT were patterned by chemical mechanical polishing (CMP) using damascene process to top electrode/ferroelectric material/bottom electrode. It is also possible to pattern the BLT thin film capacitors by CMP, however, the CMP damage was not considered in the experiments. The properties of BLT thin films were changed by the change of polishing pressure although the removal rate was directly proportional to the polishing pressure in CMP process.

• Nano
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• 제13권10호
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• pp.1850120.1-1850120.9
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• 2018

Two-dimensional poly(dimethylsiloxane) (PDMS) films with wavy patterns were studied in order to investigate reversible and irreversible wetting effects. Pre-strained, surface oxidized layers of PDMS were used to form relieved wavy geometries, on which hydrophobic functionalization was carried out in order to produce irreversible wetting effects. Wavy-patterned PDMS films showed time-dependent reversible wetting effects. The degree of surface wettability could be tuned by the choice of wavy groove geometries. And the groove geometries were controlled via $O_2$ plasma treatment and mechanical pre-straining. The pre-strained, buckled PDMS films were applied to the fabrication of hydrophobic polystyrene nano-patterns using colloidal self-assembly, where the colloids were arrayed in two-dimensional way. The wavy polystyrene films were found to be more hydrophobic relative to flat polystyrene films. The grooving methodology used in this study could be applied to enhancing the hydrophobicity of other types of polymeric thin films, eliminating the need for chemical treatment.

• 공업화학
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• 제25권1호
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• pp.53-57
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• 2014

본 연구에서는 micro-contact printing을 통하여 니오븀 호일 표면 위에 균일한 에칭 pits를 형성하였다. 균일한 보호층을 형성하고자 전해연마의 효과를 확인하였으며, 기존의 $O_2$ 플라즈마 공정 없이 손쉽게 균일한 에칭 pits를 형성시킬 수 있는 조건을 확인하였다. 메탄올 혼합 전해질을 사용하여 10 min 동안 에칭을 진행한 결과 니오븀 호일 표면 위에 지름과 간격이 각각 $10{\mu}m$와 $5{\mu}m$로 잘 정렬된 에칭 pits를 관찰하였다.

• Bulletin of the Korean Chemical Society
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• 제29권7호
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• pp.1349-1352
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• 2008

We report a novel patterning method for a homo-polymeric poly(3-hexylthiophene) (P3HT) nanofilm particularly capable of strong adhesion to a $SiO_2$ surface. An oxidized silicon wafer substrate was micro-contact printed with n-octadecyltrichlorosilane (OTS) monolayer, and subsequently its negative pattern was selfassembled with three different amino-functionalized alkylsilanes, (3-aminopropyl)trimethoxysilane (APS), N- (2-aminoethyl)-3-aminopropyltrimethoxy silane (EDAS), and (3-trimethoxysilylpropyl) diethylenetriamine (DETAS). Then, P3HT nanofilms were selectively grown on the aminosilane pre-patterned areas via the vapor phase polymerization method. To evaluate the adhesion, patterning, and the film itself, the PEDOT nanofilms and SAMs were investigated with a $Scotch^{(R)}$ tape test, contact angle analyzer, ATR-FT-IR, and optical and atomic force microscopes. The evaluation showed that the newly developed all bottom-up process can offer a simple and inexpensive patterning method for P3HT nanofilms robustly adhered to an oxidized Si wafer surface by the mediation of $FeCl_3$ and amino-functionalized alkylsilane SAMs.

• 한국표면공학회지
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• 제47권6호
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• pp.347-353
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• 2014

We present a synthesis of single-walled carbon nanotubes(SWNTs) for enhancement of parallel-alignment and density using chemical vapor deposition with methane feed gas. As-purchased ST-cut quartz substrates were heat-treated and line-patterned by electron-beam lithography in order to grow SWNTs with parallel alignment. We investigated the effects of various synthesis parameters such as catalyst oxidation, reduction, and synthesis conditions in order to enhance both tube density and degree of parallel alignment. The condition of $1{\AA}$ of Fe catalyst film, atmospheric oxidation at $750^{\circ}C$ for 10 min, reduction under 400 Torr for 5 min, and growth at $865^{\circ}C$ under 300 Torr yields $33tubes/10{\mu}m$, which is the highest tube density with parallel alignment. Based on the results of atomic force microscope and Raman spectroscopy, it was found that SWNTs have diameter range of 0.8-2.0 nm. We believe that the present work would contribute to the development of SWNTs-based flexible functional devices.

• Bulletin of the Korean Chemical Society
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• 제33권4호
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• pp.1128-1134
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• 2012

We investigated a new method for patterning organic field-effect transistors (OFETs) using a photopatternable conducting polymer nanocomposite, consisting of poly(3-hexylthiophene) (P3HT)-coated gold nanoparticles (AuNPs) that had been modified with a photoreactive cinnamate group, to form P3HT-AuNP-CI. We found that the addition of the cinnamate group to the nanoparticle surface assisted the preparation of a solvent-resistive semiconducting film and preserved the P3HT ordering, which was interrupted by Au-P3HT interactions, as well as provided UV-controllable electrical properties. The P3HT-AuNPs-CI films could be microscale-patterned via a UV crosslinking photoreaction, represented as a promising photopatternable semiconductor material for use in advanced applications, with tunable electrical properties for fabrication of sub-micron and microscale electronic devices.

• Macromolecular Research
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• 제17권3호
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• pp.192-196
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• 2009

Recently, the multi-screening of target materials has been made possible by the development of the surface plasmon resonance (SPR) imaging method. To adapt this method to biochemical analysis, the multi-patterning technology of protein microarrays is required. Among the different methods of fabricating protein microarrays, the microfluidic platform was selected due to its various advantages over other techniques. Microfluidic devices were designed and fabricated with polydimethylsiloxane (PDMS) by the replica molding method. These devices were designed to operate using only capillary force, without the need for additional flow control equipment. With these devices, multiple protein-patterned sensor surfaces were made, to support the two-dimensional detection of various protein-protein interactions with SPR. The fabrication technique of protein microarrays can be applied not only to SPR imaging, but also to other biochemical analyses.

• 마이크로전자및패키징학회지
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• 제21권1호
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• pp.13-17
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• 2014

The direct-patternable $SnO_2$ thin film was successfully fabricated by photochemical metal-organic deposition. The composition and chemical bonding state of $SnO_2$ thin film were analyzed by using X-ray photoelectron spectroscopy (XPS) from the surface to the interface with Si substrate. XPS depth profiling analysis allowed the determination of the atomic composition in $SnO_2$ film as a function of depth through the evolution of four elements of C 1s, Si 2p, Sn 3d, and O 1s core level peaks. At the top surface, nearly stoichiometric $SnO_2$ composition (O/Sn ratio is 1.92.) was observed due to surface oxidation but deficiency of oxygen was increased to the interface of patterned $SnO_2/Si$ substrate where the O/Sn ratio was about 1.73~1.75 at the films. This O deficient state of the film may act as an n-type semiconductor and allow $SnO_2$ to be applied as a transparent electrode in optoelectronic applications.

• 한국표면공학회지
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• 제49권1호
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• pp.20-25
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• 2016

Femtosecond laser ablation of ultrathin polymer films on quartz glass using laser pulses of 100 fs and centered at ${\lambda}=400nm$ wavelength has been investigated for nanometer precision thin film patterning. Single-shot ablation craters on films of various thicknesses have been examined by atomic force microscopy, and beam spot diameters and ablation threshold fluences have been determined by square diameter-regression technique. The ablation thresholds of polymer film are about 1.5 times smaller than that of quartz substrate, which results in patterning crater arrays without damaging the substrate. In particular, at a $1/e^2$ laser spot diameter of $0.86{\mu}m$, the smallest craters of 150-nm diameter are fabricated on 15-nm thick film. The ablation thresholds are not influenced by the film thickness, but diameters of the ablated crater are bigger on thicker films than on thinner films. The ablation efficiency is also influenced by the laser beam spot size, following a $w_{0q}{^{-0.45}}$ dependence.

• 한국결정성장학회지
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• 제30권1호
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• pp.1-6
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• 2020

본 연구에서는 패턴화된 사파이어 기판 위에 HVPE(Hydride Vapor Phase Epitaxy System) 법에 의해 50 nm 두께의 AlN thin film을 증착한 뒤, 에피층 구조가 MO CVD에서 성장되었다. AlN 버퍼층 박막의 표면형상이 SEM, AFM에 의해서, 에피층 구조의 GaN 박막의 결정성은 X-선 rocking curve에 의해 분석되었다. 패턴화된 사파이어 기판 위에 증착된 GaN 박막은, 사파이어 기판 위에 증착된 GaN 박막의 경우보다 XRD 피크 세기가 다소 높은 결과를 나타냈다. AFM 표면 형상에서 사파이어 기판 위에 AlN 박막이 증착된 경우, GaN 에피층 박막의 p-side 쪽의 v-pit 밀도가 상대적으로 낮았으며, 결함밀도가 낮게 관찰되었다. 또한, AlN 버퍼층이 증착된 에피층 구조는 AlN 박막이 없는 에피층의 광출력에 비해 높은 값을 나타냈다.