• 한국정밀공학회지
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• 제29권7호
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• pp.799-804
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• 2012

Recently micro-nano structures has widely been reported to improve the performance of waterproof, heat isolation, sound and light absorption in various fields of electric devices such as mobiles, battery, display and solar panels. A lot of micro-sized holes on the surface of thin film provide excellent sound, or heat, or light transmission efficiency more than solid film and simultaneously nano-sized protrusions around micro hole increase the hydrophobicity of the surface of thin film because of lotus leaf effects as generally known previously. In this paper new rapid fabrication process with 355 nm UV laser ablation was proposed to get micro-nano structures on the surface of thin film, which have only been observed at higher laser fluence. Developed thin micro-nano structured film was also investigated the hydrophobic property by measuring the contact angle and demonstrated the possibility to apply to water droplet separation.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.120-122
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• 2005

An alumina membrane with nano-sized pore array by anodic oxidation using thin film aluminum deposited on silicon wafer was fabricated. It is important that the sample prepared by metal deposition method has a flat aluminum surface and a good adhesion between the silicon wafer and the thin film aluminum. The oxidation time was controlled by observation of current variation. While the oxalic acid with 0.2M was used for low voltage anodization under 100V, the chromic acid with 0.1M was used for high voltage anodization over 100V. The nano-sized pores with diameter of 60~120nm was obtained by low voltage anodization of 40~90V and those of 200~300nm was obtained by high voltage anodization of 120~160V. Finally, the sample was immersed to the phosphoric acid with 0.1M concentration to etching the barrier layer. The sample will be applied to electronic sensors, field emission display, and template for nano-structure.

• 한국정보통신학회논문지
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• 제10권9호
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• pp.1641-1647
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• 2006

나노입자 크기를 가진 얇은 $SnO_2$ 박막을 이용하여 CO 및 $H_2S$에 대한 우수한 감도를 가지는 복합 마이크로 가스센서 어레이를 제작하였다. 나노입자의 박막을 만들기 위해서 약 $2500{\AA}$ 두께의 $SnO_2,\;SnO_2(+Pt),\;SnO_2(+CuO)$ 막을 셰도우마스크를 사용하여 형성 한 후, 이를 $600{\sim}800^{\circ}C$의 온도에서 산화하므로서 나노입자의 $SnO_2$ 모물질의 가스감지 박막을 형성하였다. 실리콘 기판의 마이크로센서의 형태로 제작된 $SnO_2(Pt)$ 및 $SnO_2(+CuO)$ 가스센서는 각각 CO 및 $H_2S$ 가스에 대한 매우 우수한 감도를 나타내는 것을 확인하였다.

• 한국전기전자재료학회논문지
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• 제18권8호
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• pp.708-713
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• 2005

An alumina membrane with nano-sized pore array by anodic oxidation using the thin film aluminum deposited on silicon wafer was fabricated. It Is important that the sample prepared by metal deposition method has a flat aluminum surface and a good adhesion between the silicon wafer and the thin film aluminum. The oxidation time was controlled by observation of current variation. While the oxalic acid with 0.2 M was used for low voltage anodization under 100 V, the chromic acid with 0.1 M was used for high voltage anodization over 100 V. The nano-sized pores with diameter of $60\~120$ nm was obtained by low voltage anodization of $40\~80$ V and those of $200\~300$ nm was obtained by high voltage anodization of $140\~200$ V. The pore widening process was employed for obtaining the one-channel with flat surface because the pores of the alumina membrane prepared by the fixed voltage method shows the structure of two-channel with rough surface. Finally, the sample was immersed to the phosphoric acid with 0.1 M concentration to etching the barrier layer.

• 한국재료학회지
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• 제24권10호
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• pp.532-537
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• 2014

In this study, highly sensitive hydrogen micro gas sensors of the multi-layer and micro-heater type were designed and fabricated using the micro electro mechanical system (MEMS) process and palladium catalytic metal. The dimensions of the fabricated hydrogen gas sensor were about $5mm{\times}4mm$ and the sensing layer of palladium metal was deposited in the middle of the device. The sensing palladium films were modified to be nano-honeycomb and nano-hemisphere structures using an anodic aluminum oxide (AAO) template and nano-sized polystyrene beads, respectively. The sensitivities (Rs), which are the ratio of the relative resistance were significantly improved and reached levels of 0.783% and 1.045 % with 2,000 ppm H2 at $70^{\circ}C$ for nano-honeycomb and nano-hemisphere structured Pd films, respectively, on the other hand, the sensitivity was 0.638% for the plain Pd thin film. The improvement of sensitivities for the nano-honeycomb and nano-hemisphere structured Pd films with respect to the plain Pd-thin film was thought to be due to the nanoporous surface topographies of AAO and nano-sized polystyrene beads.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.252-257
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• 2004

Nanometer-sized structures are being applied to many devices including micro/nano electronics, optoelectronics, quantum devices, MEMS/NEMS, biosensors, etc. Especially, the thin film with submicron thickness is a basic structure for fabricating these devices, but its mechanical behaviors are not well understood. The mechanical properties of the thin film are different from those of the bulk structure and are difficult to measure because of its handling inconvenience. Several techniques have been applied to mechanical characterization of the thin film, such as nanoindentation test, micro/nano tensile test, strip bending test, etc. In this study, we focus on the strip bending test because of its high accuracy and moderate specimen preparation efforts, and measure Au thin film, which is a very popular material in micro/nano electronic devices. Au film is deposited on Si substrate by evaporation process, of which thickness is 100nm. Using the strip bending test, we obtain elastic modulus, yield and ultimate tensile strength, and residual stress of Au thin film.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.1621-1624
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• 2008

Transparent ac-PDP test panel was prepared via a combination of materials including ITO sustaining electrodes, thin film dielectric layer and nano-sized phosphor powders. The thin film dielectric layer was prepared by E-beam evaporation process and phosphor layer was deposited on metal mesh pattern by electrophoretic deposition process. The optical transmittance and luminance of the panel indicated that full color transparent ac-PDP is feasible with the approach.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.1971-1973
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• 2005

We fabricated an alumina membrane with nano-sized pore array by anodic oxidation using the thin film aluminum deposited on silicon wafer. It is important that the sample prepared by metal deposition method has a flat aluminum surface and a good adhesion between the silicon wafer and the thin film aluminum. The oxidation time was controlled by observation of current variation. The nano-sized pores with diameter of $60{\sim}120nm$ was obtained by $40{\sim}80$ voltage. The pore widening process was employed for obtaining the flat surface because the pores of the alumina membrane prepared by the fixed voltage method shows the structure of rough surface. Finally, the sample was immersed to the phosphoric acid with 0.1M concentration to etching the barrier layer. The sample will be applied to electronic sensors, field emission display, and template for nano- structure.

• Journal of Magnetics
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• 제19권3호
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• pp.232-236
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• 2014

Anisotropy coupling in thin films with mixed induced and shape anisotropies is investigated. A 200-nm-thick Co-Fe-Pd-B thin film with a large induced anisotropy of 57 Oe is fabricated and then patterned into micron-sized cells to provide shape anisotropy, whose strength has a similar magnitude to that of the induced anisotropy for enhancing the anisotropy coupling. The angles between the two mixed anisotropies considered are $0^{\circ}$, $90^{\circ}$, and $110^{\circ}$. Hysteresis loops measured under in-plane magnetic fields along various directions indicate no anisotropy coupling behaviour for all the three angles examined in this study.

• 한국재료학회지
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• 제19권6호
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• pp.325-329
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• 2009

Titanium dioxide thin films were fabricated as hydrogen sensors and its sensing properties were tested. The titanium was deposited on a $SiO_2$/Si substrate by the DC magnetron sputtering method and was oxidized at an optimized temperature of $850^{\circ}C$ in air. The titanium film originally had smooth surface morphology, but the film agglomerated to nano-size grains when the temperature reached oxidation temperature where it formed titanium oxide with a rutile structure. The oxide thin film formed by grains of tens of nanometers size also showed many short cracks and voids between the grains. The response to 1% hydrogen gas was ${\sim}2{\times}10^6$ at the optimum sensing temperature of $200^{\circ}C$, and ${\sim}10^3$ at room temperature. This extremely high sensitivity of the thin film to hydrogen was due partly to the porous structure of the nano-sized sensing particles. Other sensor properties were also examined.