• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 춘계학술발표강연 및 논문개요집
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• pp.53-53
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• 2003

There has been increasing interest in the fabrication of nano-sized structures because of their various advantages and applications. Anodic Aluminum Oxide (AAO) is one of the most successful methods to obtain highly ordered nano pores and channels. Also It can be obtained diverse pore diameter, density and depth through the control of anodization condition. The three types of substrates were used for anodization; sheets of Aluminum on Si wafer and Aluminum on Mo-coated Si wafer. In Aluminum sheet, a highly ordered array of nanoholes was formed by the two step anodization in 0.3M oxalic acid solutions at 10$^{\circ}C$ After the anodization, the remained aluminum was removed in a saturated HgCl$_2$ solution. Subsequently, the barrier layer at the pore bottom was opened by chemical etching in phosphoric acid. Finally, we can obtain the through-channel membrane. In these processes, the effect of various parameters such as anodizing voltage, anodizing time, pore widening time and pre-heat treatment are characterized by FE-SEM (HITACH-4700). The pore size. density and growth rate of membrane are depended on the anodizing voltage and temperature respectively. The pore size is proportional to applied voltage and pore widening time The pore density can be controlled by anodizing temperature and voltage.

• 한국진공학회지
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• 제6권4호
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• pp.321-325
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• 1997

LCD용 칼라 필터를 제작하는 방법으로 감광성 고분자(photosensitive polymer)에 광 리소그라피(photolithography)기술이 많이 이용되어지고 있다. 이로 인해 감광성 고분자 표 면의 물리적, 화학적 성질이 변하게 되는데, 이는 후속 공정인 플라즈마 식각이나 ITO 전극 의 증착 등에도 많은 영향을 주므로, 각 공정에 따른 이들 고분자의 표면 연구는 매우 중요 하다. 본 논문에서는 blue 칼라 필터의 고분자 표면에 대한 연구를 SIMS와 XPS를 이용하 여 수행하였으며, 표면의 거칠기 변화를 AFM을 통해 관찰하였다. SIMS와 XPS결과로부터 초기 공정인 blue 칼라 필터를 스핀 코팅하고 pre bake한 상태에서는 주로 칼라 필터의 주 성분인 단량체와 결합제의 고분자 물질이 표면에 드러나 있다가, 노광 과정을 거치고 post bake한 시료에서는 색깔을 내는 안료 성분이 표면에 드러남을 확인하였고, AFM을 통해서 는 post bake후에 표면에 더 거칠어 짐을 관찰하였다.

• 한국진공학회지
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• 제8권4B호
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• pp.514-518
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• 1999

Gold (Au) is not supposed to react with sapphire(single crystalline ) under thermodynamic equillibrium, therefore, a strong adhesion between these two dissimilar materials is not expected. However, pull test showed that the gold film sputter-deposited onto annealed and pre-sputtered sapphire exhibited very strong adhesion even without post-deposition annealing. Strongly and weakly adhered samples as a result of the pull testing were selected to investigate the adhesion mechanisms with Auger electron spectroscopy. The Au/ interfaces were analyzed using a new technique that probes the interface on the film using Auger electron escape depth. It revealed that one or two monolayers of Au-Al-O compound formed at the Au/Sapphire interface when AES in the UHV chamber. It showed that metallic aluminum was detected on the surface of sapphire substrates after irradiating for 3 min. with 7keV Ar+ -ions. These results agree with TRIM calculations that yield preferential ion-beam etching. It is concluded that the formation of Au-Al-O compound, which is responsible for the strong metal-ceramic bonding, is due to ion-induced cleaning and reduction of the sapphire surface, and the kinetic energy of depositing gold atoms, molecules, and micro-particles as a driving force for the inter-facial reaction.

• 한국전자파학회지:전자파기술
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• 제14권3호
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• pp.15-19
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• 2003

본 연구에서는 RF magnetron sputtering으로 상온에서 증착된 ZnO압전박막을 이용하여, 1.96 GHz 대역의 air gap type의 FBAR BPF를 개발하였다. FBAR BPF는 Si wafer에 절연막으로 열 산화막층(SiO$_2$)을 형성한 후, 형성된 산화막 위에 바닥전극(Al), ZnO압전층 그리고 상부전극(Mo)를 차례로 RF magnetron sputter장비를 사용하여 증착시키고, Si wafer를 dry etching하여 air hole을 구현함으로써 device를 제조하였다. 제조된 FBAR BPF의 ZnO압전층의 XRD분석 결과 (002)면 방향으로 우선 배향되었으며, XRC의 $\sigma$값은 1.018이었다. 삽입손실 1 dB 내외로 우수한 특성을 나타내었다.

• 산업기술연구
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• 제39권1호
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• pp.33-39
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• 2019

This paper addresses effects of nanoscale structures on structural colors of micropatterned transparent substrate by light diffraction. Structural colors is widely investigated because they present colors without any chemical pigments. Typically structural colors is presented by diffraction of light on a micropatterned surface or by multiple interference of light on a surface containing a periodic or quasi-periodic nano-structures. In this paper, each structural colors induced by quasi-periodic nano-structures, periodic micro-structures, and nano/micro dual structures is measured in order to investigate effects of nanoscale and microscale structures on structural colors in the transparent substrate. Using pre-fabricated pattern mold and hot-embossing process, nanoscale and microscale structures are replicated on the transparent PMMA(Poly methyl methacrylate) substrate. Nanoscale and microscale pattern molds are prepared by anodic oxidation process of aluminum sheet and by reactive ion etching process of silicon wafer, respectively. Structural colors are captured by digital camera, and their optical transmittance spectrum are measured by UV/visible spectrometer. From experimental results, we found that nano-structures provide monotonic colors by multiple interference, and micro-structures induce iridescent colors by diffraction of light. Structural colors is permanent and unchangeable, thus it can be used in various application field such as security, color filter and so on.

• 대한소아치과학회지
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• 제37권4호
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• pp.445-452
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• 2010

최근 CPP-ACP의 초기 우식증의 재광화 및 예방 효과에 대한 연구가 많이 진행되고 있다. 그러나, CPP-ACP 적용으로 인한 법랑질 산부식 저항성 증가가 치면열구전색제 접착에 미치는 영향에 대해서는 연구가 부족한 실정이다. 본 연구에서는 CPP-ACP의 치면 도포 여부와 치면열구전색제의 접착 방법의 차이가 법랑질과 치면열구전색제의 결합력에 미치는 영향에 대하여 미세전단결합강도 측정법으로 알아보고자 하였다. 건전한 제3대구치를 사용하여 150개의 시편을 제작하였으며, 다음과 같이 6군으로 나누었다. I군: 인공타액에 2주 보관 후 35% 인산 산부식 II군: 인공타액에 2주 보관 후 35% 인산 산부식 + 접착제 III군: 인공타액에 2주 보관 후 자가 부식 접착제 IV군: CPP-ACP 2주 적용 후 35% 인산 산부식 V군: CPP-ACP 2주 적용 후 35% 인산 산부식 + 접착제 VI군: CPP-ACP 2주 적용 후 자가 부식 접착제 6군의 시편에 치면열구전색제 접착 후 미세전단결합강도를 측정하여 다음과 같은 결과를 얻었다. CPP-ACP 적용은 전통적인 산부식 방법으로 치면열구전색제를 접착하는 경우에는 결합강도와 산부식 양상에 영향을 미치지 않으나, 자가 부식 접착제를 사용한 경우에는 치면열구전색제의 결합강도를 약화시켰다.

• Transactions on Electrical and Electronic Materials
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• 제14권3호
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• pp.133-138
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• 2013

Acrylonitrile-butadiene-styrene (ABS) plastic is a polymer material extensively used in electrical and electronic applications. Nickel (Ni) thin film was deposited on ABS by electroless plating, after its surface was treated and modified with atmospheric plasma generated by means of dielectric barrier discharges (DBDs) in air. The method in this study was developed as a pre-treatment for electroless plating using DBDs, and is a dry process featuring fewer processing steps and more environmentally friendliness than the chemical method. After ABS surfaces were modified, surface morphologies were observed using a scanning electron microscope (SEM) to check for any physical changes of the surfaces. Cross-sectional SEM images were taken to observe the binding characteristics between metallic films and ABS after metal plating. According to the SEM images, the depths of ABS by plasma are shallow compared to those modified by chemically treatment. The static contact angles were measured with deionized (DI) water droplets on the modified surfaces in order to observe for any changes in chemical activities and wettability. The surfaces modified by plasma showed smaller contact angles, and their modified states lasted longer than those modified by chemical etching. Adhesion strengths were measured using 3M tape (3M 810D standard) and by 90° peel-off tests. The peel-off test revealed the stronger adhesion of the Ni films on the plasma-modified surfaces than on the chemically modified surfaces. Thermal shock test was performed by changing the temperature drastically to see if any detachment of Ni film from ABS would occur due to the differences in thermal expansion coefficients between them. Only for the plasma-treated samples showed no separation of the Ni films from the ABS surfaces in tests. The adhesion strengths of metallic films on the ABS processed by the method developed in this study are better than those of the chemically processed films.

• 한국대기환경학회지
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• 제27권1호
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• pp.1-15
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• 2011

Korea Global Atmosphere Watch Center (KGAWC), which is located in Anmyeondo and, belongs to the Korea Meteorological Administration (KMA), measures sulfur hexafluoride ($SF_6$) in every hour since 2007. In this study, $SF_6$ observed in 2007 are discussed. A gas chromatograph-electron capture detector (GC-ECD) with pre-cooled device is applied during the observation, and produced data are qualified by means of periodic calibration with $SF_6$ standard gas made by Korea Research Institute of Standard and Science (KRISS). $SF_6$ has been greatly paid attention since Kyoto protocol because of its high global warming potential(GWP) with 22,200 times of $CO_2$ in the period of 100 years. It is a man-made compound and has been usually used for gas insulation since 1970s and for etching process in the information technology-based industry since 1990. Average mixing ratio of $SF_6$ in 2007 was 6.65 pmol/mol at Anmyeondo. According to the GAW report published in 2008, average mixing ratio of $SF_6$ in the atmosphere is continuously growing. At present, the average mixing ratio of $SF_6$ in the atmosphere is known to be approximately 6.25 pmol/mol at global observatory. $SF_6$ value in Anmyeondo shows 0.40 pmol/mol greater than that of the Mauna Loa observatory in 2007.

• 대한소아치과학회지
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• 제32권2호
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• pp.191-199
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• 2005

본 연구는 매복된 치아를 교정력을 이용하여 견인할 때 견인의 대상이 되는 치아를 개창술로 노출시켜 브라켓을 부착하는 과정에서 혈액 오염이 일어날 수 있는 상황을 실험실 환경에서 재현한 다음, 이와 같은 오염의 유무와 접착제의 종류가 브라켓의 전단강도에 미치는 영향을 평가하기 위해 시행하였다. 본 연구의 결과 글래스 아이오노머의 전단 강도는 레진에 비해 모든 조건에서 낮은 수치를 보였으나 혈액 오염이 없거나 광조사 직전 오염된 경우 임상적으로 교정적 정출술에 적절한 전단 강도를 나타내었다. 두 재료 모두 접착제 적용 전에 치면이 혈액에 오염되었을 경우 다른 조건에 비해 현저하게 낮은 전단 강도를 보였으나 광조사 직전에 혈액에 오염되었을 경우에는 오염되지 않은 대조군과 유의한 차이가 없었다. 이상의 연구 결과, 개창술을 통해 브라켓을 부착할 경우 접착제 적용 직전 혈액 오염을 주의한다면 산부식 과정 이 생략되어 술식이 비교적 간단하고 접착 파절 후 치면에 접착제가 남아 있지 않은 장점을 지닌 글래스 아이오노머 접착제의 사용을 추천할 수 있을 것으로 사료된다.

• Current Photovoltaic Research
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• 제1권1호
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• pp.63-68
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• 2013

We investigated the effects of Au eutectic reaction on Si thin film growth by hot wire chemical vapor deposition. Small SiC and Si nano-particles fabricated through a wet etching process were coated and biased at 50 V on micro-textured Si p-n junction solar cells. Au thin film of 10 nm and a Si thin film of 100 nm were then deposited by an electron beam evaporator and hot wire chemical vapor deposition, respectively. The Si and SiC nano-particles and the Au thin film were structurally embedded in Si thin films. However, the Au thin film grew and eventually protruded from the Si thin film in the form of Au silicide nano-balls. This is attributed to the low eutectic bonding temperature ($363^{\circ}C$) of Au with Si, and the process was performed with a substrate that was pre-heated at a temperature of $450^{\circ}C$ during HWCVD. The nano-balls and structures showed various formations depending on the deposited metals and Si surface. Furthermore, the samples of Au nano-balls showed low reflectance due to surface plasmon and quantum confinement effects in a spectra range of short wavelength spectra range.