• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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• pp.1645-1646
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• 2006

Micro ElectroMechanical Systems (MEMS) 기술을 이용한 초미세 유체 제어 시스템 (마이크로 펌프, 마이크로 밸브, 마이크로 채널, 마이크로 믹서 등)은 화학, 생명분야의 DNA 분석, 항원-항체 분석, 질병의 진단 등에 사용되는 lab-on-a-chip, micro total analysis system ($\mu$-TAS) 등에서 화학 및 바이오 유체를 제어하는 분석 시스템의 일부분으로서 사용되며 필수적으로 요구된다. 본 논문에서는 이러한 microchip을 구현하기 위해 초미세 유체 제어 소자인 마이크로 펌프와 밸브를 같은 기관 위에 polydimethylsiloxane (PDMS)와 indium tin oxide (ITO)-Glass를 사용하여 동일한 구조로 집적 하였다. 마이크로 펌프의 pumping rate은 인가 직류 펄스 전력의 주파수와 duty 비를 변화시켜 최적화하였다. 직류 펄스 전력 500 mW를 인가하였을 때 주파수 2 Hz, duty 비 7 %에서 약 $1.05{\mu}l/min$의 최대 유량이 측정되었다. 마이크로 밸브는 ITO 히터에 전력을 인가함으로서 유량의 on/off 제어가 잘 됨을 확인할 수 있었고 유체를 closing하기 위해 필요한 전력은 약 300 mW이다.

• 한국산학기술학회논문지
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• 제10권7호
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• pp.1514-1519
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• 2009

400nm 파장을 방출하는 GaN LED를 제조하여, n-GaN층과 p-GaN층의 위에 있는 ITO층 표면에 패턴을 만들어 광 추출 효율을 향상시켰다. 추가적으로, n과 p패드 아래와 칩의 바닥면에 각각 광반사 금속을 설치하였다. 광 추출 효율은 20mA에서 n-GaN의 텍스쳐링에 의해 20% 증가되었고 ITO의 텍스쳐링에 의해 18% 증가되었다. 표면 처리가 않된 LED와 비교해서 n-GaN와 ITO를 함께 표면 텍스쳐링 했을때의 광 추출 효율은 20mA에서 32% 증가되었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.379-380
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• 2007

The characteristics of a co-sputtered indium zinc tin oxide (IZTO) films prepared by dual target dc magnetron sputtering from IZO and ITO targets at a room temperature are investigated. Film properties, such as sheet resistance, optical transmittance, surface work function and surface roughness were examined as a function of ITO dc power at constant IZO dc power of 100 W. It was shown that the increase of the ITO dc power during co-sputtering of ITO and IZO target resulted in an increase of sheet resistance of the IZTO films. This can be attributed to high resistivity of ITO film prepared at room temperature. Surface smoothness and roughness were investigated by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The synchrotron x-ray scattering results obtained from IZTO film with different ITO contents showed that introduction of ITO atoms into amorphous IZO film resulted in a crystallization of IZTO film with (222) preferred orientation due to low alc transition temperature of ITO film. However, the transmittance of the IZTO films with thickness of 150 nm is between 80 and 85 % at wavelength of 550 nm regardless of ITO content. Possible mechanism to explain the ITO and IZO co-sputtering effect on properties of IZTO is suggested.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.398-398
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• 2007

The Liquid Crystal (LC) alignment uniformity is very important in LC devices. The alignment mechanism of LC molecules on a rubbed polyimide (PI) surface is very important for both LC fundamental research and application. So, Generally a rubbing method to align LC has been widely used to mass-produce LCD panels. But because rubbing method is contact method between rubbing fabric and indium-tin-oxide glass or flexible substrate, rubbing method has some defects, such as the electrode charges and the creation of contaminating particles. Thus we strongly recommend a non-contact alignment technique for getting rid of some defects of rubbing method. Most recently, the LC aligning capabilities achieved by ion-beam exposure on the organic and nonorganic thin film surface have been reported successfully. In this research, we studied the tilt angle generation and electro-optical performances for a NLC on homeotropic polyimide surfaces with ion-beam exposure. The LC aligning capabilities of a nematic liquid crystal (NLC) on a homeotropic PI surface using a new ion-beam method were studied. On the homeotropic PI surface, the tilt angle of the NLC by exposure ion-beam had a tendency to decrease as increased ion-beam energy density. And, on the homeotropic PI surface, the alignment character of the NLC with respect to ion-beam energy was good. And we achieved satisfactory result for EO character.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.165-165
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• 2007

투명전도박막은 ITO, $SnO_2$, ZnO, 등이 있으나 $SnO_2$는 자외선 영역까지 투과시키는 우수한 광학적 특성을 나타내지만, 상당히 큰 전기저항으로 인해 현재는 현재 ITO가 널리 이용되고 있다. ITO(Indium Tin Oxide)박막은 자외선 영역에서 반사율이 높으며 가시광선영역에서는 80%이상의 뛰어난 투과율을 가지고 있다. 또한 낮은 전기저항과 넓은 광학적 밴드갭 때문에 가장 유용한 투과전도성 재료 중에 하나이다. 이러한 특성 때문에 여러 가지 문자 표시소자의 투명전극, 태양전지의 창재료, 정전차폐를 위한 반도체 포장재료, 열반사막, 면발열체, 광전변환 소자에 응용되고 있다. 일반적으로 박막의 제작에는 저항가열법과 전자선가열법, 스퍼터링법의 물리적 증착과 화학적 증착으로 나뉜다. 본 논문에서는 증착온도를 달리 하여 RF-sputtering에 의해 ITO박막을 증착한 후 온도증가에 따른 박막의 특성을 연구하였으며 또한 광역평탄화를 위한 CMP공정을 적용하여 증착온도가 연마에 미치는 영향을 연구하였다. 본 실험에서 사용된 ITO박막은 $2{\times}2Cm$의 Corning glass위에 증착되었으며 타겟은 $In_2O_3$와 $SnO_2$가 9:1로 혼합된 Purity 99.99%이상의 직경 2 inch인 ITO타겟을 사용하였다. 박막 증착시 기판온도는 상온에M $200^{\circ}C$까지 변화시켰으며 RF power는 100W로 일정하게 하였으며 증착압력은 $8{\times}10^{-2}$Torr이였다. CMP공정조건은 헤드속도 60rpm, 플레이튼 속도 60rpm, 슬러리 주입 유량 60mml/min, 압력 $300g/cm^2$이였다. 전기적 특성은 four point probe를 이용하여 측정하였으며 광학적 특성은 UV-Visible Spectrometer를 이용하여 200~900nm의 파장범위에서 광투과도를 측정하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.430-430
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• 2007

In this study, the nematic liquid crystal (NLC) alignment effects treated on the ZnO thin film layers using ion beam irradiation were successfully studied for the first time. The ZnO thin films were deposited on indium-tin-oxide (ITO) coated glass substrates by rf-sputter and The ZnO thin films were deposited at the three kinds of rf power. The used DuoPIGatron type ion beam system, which can be advantageous in a large area with high density plasma generation. The ion beam parameters were as follows: energy of 1800 eV, exposure time of 1 min and ion beam current of $4\;mA/cm^2$ at exposure angles of $15^{\circ}$, $30^{\circ}$, $45^{\circ}$, and $60^{\circ}$. The homogeneous and homeotropic LC aligning capabilities treated on the ZnO thin film surface with ion beam exposure of $45^{\circ}$ for 1 min can be achieved. The low pretilt angle for a NLC treated on the ZnO thin film surface with ion beam irradiation for all incident angles was measured. The good LC alignment treated on the ZnO thin film with ion beam exposure at rf power of 150 W can be measure. For identifying surfaces topography of the ZnO thin films, atomic force microscopy (AFM) was introduced. After ion beam irradiation, test samples were fabricated in an anti-parallel configuration with a cell gap of $60{\mu}m$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.307-310
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• 1999

Using Se as a photoconductive element and ZnS as a luminescent element, a Se/ZnS thin film device for light amplifier applications was fabricated and its characteristics were investigated. The Se/ZnS thin film light amplifier was fabricated by evaporating the ZnS thin film on an ITO(Indium Tin Oxide) glass and the Se thin film on the ZnS thin film in sequence. The results of the characteristics investigation are summarized as follows: (1) When the frequency of an excitation voltage was increased, both the brightness response and the brightness saturation of the Se/ZnS thin film light amplifier began to start at a higher light input. (2) The gain of the Se/ZnS thin film light amplifier was dependent upon the amplitude and the frequency of the excitation voltage as well as an external light input. (3) When the Se/ZnS thin film light amplifier was excited by a direct current of a constant voltage, the frequency of the output brightness was\\`equal to the frequency of the input light applied. When the light amplifier was excited by a sinusoidal voltage of 60 Hz, the frequency of the output brightness was 120 Hz.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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• pp.158-161
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• 2004

We have studied a lifetime in organic light-emitting diodes depending on buffer layer. A transparent electrode of indium-tin-oxide(ITO) was used as an anode. And the cathode for electron injection was LiAl. Phthalocyanine Copper(CuPc), Poly(3,4-ethylenedioxythiophene):poly (PEDOT:PSS), or poly (9-vinylcarbazole)(PVK) material was used as a buffer layer. A thermal evaporation was performed to make a thickness of 40nm of TPD layer at a rate of $0.5{\sim}1\;{\AA}/s$ at a base pressure of $5{\times}10^{-6}\;torr$. A material of tris(8-hydroxyquinolinate) Aluminum($Alq_3$) was used as an electron transport and emissive layer. A thermal evaporation of $Alq_3$ was done at a deposition rate of $0.7{\sim}0.8[{\AA}/s]$ at a base pressure of $5{\times}10^{-6}\;torr$. By varying the buffer material, hole injection at the interface could be controlled because of the change in work function. Devices with CuPc and PEDOT:PSS buffer layer are superior to the other PVK buffer layer.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.450-450
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• 2006

Organic light-emitting diodes (OLED) as pixels for flat panel displays are being actively pursued because of their relatively simple structure, high brightness, and self-emitting nature [1, 2]. The top-emitting diode structure is preferred because of their geometrical advantage allowing high pixel resolution [3]. To enhance the performance of TOLEDs, it is important to deposit transparent top cathode films, such as transparent conducting oxides (TCOs), which have high transparency as well as low resistance. In this work, we report on investigation of the characteristics of an indium tin oxide (ITO) cathode electrode, which was deposited on organic films by using a radio-frequency magnetron sputtering method, for use in top-emitting organic light emitting diodes (TOLED). The cathode electrode composed of a very thin layer of Mg-Ag and an overlaying ITO film. The Mg-Ag reduces the contact resistivity and plasma damage to the underlying organic layer during the ITO sputtering process. Transfer length method (TLM) patterns were defined by the standard shadow mask for measuring specific contact resistances. The spacing between the TLM pads varied from 30 to $75\;{\mu}m$. The electrical properties of ITO as a function of the deposition and annealing conditions were investigated. The surface roughness as a function of the plasma conditions was determined by Atomic Force Microscopes (AFM).

• 한국전기전자재료학회논문지
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• 제24권10호
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• pp.817-821
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• 2011

We have proposed an optical thin film and micro lens to improve the luminance of organic light emitting device. The first method, optical thin film was calculated refractive index of dielectric layer material that was modulated refractive index of organic material, ITO (indium tin oxide)and glass. The second method, microlens was applied with lenses on the organic device. Optical thin films were designed with Macleod Simulator and Micro Lenses were calculated by FDTD (finite-difference time-domain) solution. The structure of thin film was designed in organic material/ITO/dielectric layer/glass. The lenses size, height and distance were 5 ${\mu}m$, 1 ${\mu}m$, 1 ${\mu}m$, respectively. The material of micro lenses used silicon dioxide. Result, The highest luminance of OLED which applied with microlens was 11,185 $cd/m^2$, when approval voltage was 14.5 V, applied thin film was 5,857 $cd/m^2$. The device efficiency applying microlens increased 3 times than the device which does not apply microlens.