• Journal of the Korean Ceramic Society
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• v.39 no.3
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• pp.233-239
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• 2002

Reflection properties of $SiO_2$/ITO (Indium Tin Oxide) thin films coated for electromagnetic shielding, anti-static and anti-reflection on the front surface in CRT were studied. The behavior of reflectance as a function of thickness of $SiO_2$/ITO was investigated and applied to theoretical anti0reflection model of double layers and three layers. As the thickness of ITO layer increased, the deviation from theoretical value increased because uniformity of film deteriorated by pore. Because of the effect of mixed layer of $SiO_2$ and ITO, experimental reflectance showed better acceptance to the three layer antireflection model of $SiO_2$/$SiO_2$+ITO/ITO than the two layer model. Based on the theoretical antireflection design, the double layer whose thickness of $SiO_2$ and ITO were 90, 65 nm, respectively appear 2.5% in reflectance at standard wavelength, 550 nm. This phenomenon was similar to theoretical reflectance in visual range.

• Journal of the Korean institute of surface engineering
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• v.42 no.1
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• pp.21-25
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• 2009

Using an evaporation system, $SiO_2$ was deposited as a buffer layer between a PET substrate and a ITO layer and then ITO/$SiO_2$/PET layers were annealed for 1.5 hours at the temperature of $180^{\circ}C$. Adhesion and electro-optical properties of ITO films were studied with thickness variance of a $SiO_2$ buffer layer. As a result of introduction of the $SiO_2$ buffer layer, sheet resistance and resistivity increased and a ITO film with optimum sheet resistance ($529.3{\Omega}/square$) for an upper ITO film of resistive type touch panel could be obtained when $SiO_2$ of $50{\AA}$ was deposited. And it was found that ITO films with $SiO_2$ buffer layer have higher transmittance of $88{\sim}90%$ at 550 nm wavelength than ITO films with no buffer layers and the transmittance was enhanced as $SiO_2$ thickness increased from $50{\AA}$ to $100{\AA}$. Adhesion property of ITO films with $SiO_2$ buffer layers became better than ITO films with no buffer layers and this property was independent of $SiO_2$ thickness variance ($50{\sim}100{\AA}$). By depositing a $SiO_2$ buffer layer of $50{\AA}$ on the PET substrate and sputtering a ITO thin film on the layer, a ITO film with enhanced adhesion, electro-optical properties could be obtained.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.6
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• pp.1069-1074
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• 2022

In this study, we prepared ITO thin films on the Nb₂O₅/SiO₂ double buffer layer and investigated electrical and optical properties according to the change of SiO₂ buffer layer thickness (40~50nm). The ITO thin film fabricated on the Nb₂O₅/SiO₂ double buffer layer exhibited a broad surface roughness with a small value ranging of 0.815 to 1.181nm, and the sheet resistance was 99.3 to 134.0Ω/sq. It seems that there is no problem in applying the ITO thin film to a capacitive touch screen panel. In particular, the average transmittance in the short-wavelength (400~500nm) region and the chromaticity (b^*) of the ITO thin film deposited on the Nb₂O₅(10nm)/SiO₂(40nm) double buffer layer showed significantly improved results as 83.58% and 0.05, respectively, compared to 74.46% and 4.28 of ITO thin film without double buffer layer. As a result, it was confirmed that optical properties such as transmittance in the short-wavelength region and chromaticity were remarkably improved due to the index matching effect in the ITO thin film with the Nb₂O₅/SiO₂ double buffer layer.

• Korean Journal of Materials Research
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• v.12 no.1
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• pp.94-99
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• 2002

The electrical properties of porous $SiO_2/ITO$ nano thin film were studied by complex impedance and conductive mechanisms were analyzed. According to the results of complex impedance, the activation energy of $SiO_2/ITO$ and $Zn-SiO_2/ITO$ were 0.309 eV, 0.077 eV in below $450^{\circ}C$ and 0.147 eV in over $450^{\circ}C$, respectively. In case of $SiO_2/ ITO$, slightly direct tunneling occurred at room temperature. The contribution for conduction was very tiny because of high barrier of silica. However, the conductivity abruptly increased in over $300^{\circ}C$ by Thermally assisted tunneling. In case of $Zn-SiO_2/ITO$, high conductivity in 1.26 ${\Omega}^{ -1}{cdot}cm^{-1}$ at room temperature appeared by space charge conduction or Frenkel-poole emission that Zn ions play a role as localized electron states.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.244-244
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• 1999

Liquid Crystal Displays(LCDs) 투명성 전도막으로 사용하는 Indium Tin Oxide (ITO)의 고밀도 식각특성을 조사하였다. 특히 ITO식각의 경우, pixel electrode 전극에서 사용되는 underlayer인 SiO2, Si3N4와의 최적의 선택비를 얻는데 중점을 두고 있다. 따라서 본 실험에서는 Inductively Coupled Plasma(ICP)를 이용하여 source power, gas combination, bias voltage, pressure 및 기판온도에 따른 ITO의 식각 특성과 이의 underlayer인 SiO2, Si3N4와의 선택비를 조사하였다. Ar과 CH4를 주된 식각가스로서 사용하였으며 첨가가스로는 O2와 HBr를 사용하였다. ITO의 식각특성을 이해하기 위하여 Quadruple Mass Spectrometry(QMS), Optical emission spectroscopy(OES) 이용하였으며, 식각된 sample의 잔류물을 조사하기 위하여 X-ray photoelectron spectroscopy(XPS)를 이용하여 분석하였다. Ar gas에 적정량의 CH4 혼합이 순수한 Ar 가스로 식각한 경우에 비하여 ITO와 SiO2, Si3N4의 선택비가 높았으며, 더 높은 식각 선택비를 얻기 위하여 Ar/CH 분위기에서 첨가가스 O2, HBr을 사용하였다. Source power 및 bias 증가에 따라 ITO의 식각률은 증가하나, underlayer와의 선택비는 감소함을 보였다. 본 실험에서 측정된 ITO의 high 식각률은 약 1500$\AA$/min이며, SiO2, Si3N4와의 high selectivity는 각각 7:1, 12:1로 나타났다. ITO의 etchrate 및 선택비는 source power, bias, pressure, CH 가스첨가에 의존하였지만 기판온도에는 큰 변화가 없음을 관찰하였다. 또한 적정량의 가스조합으로 식각된 시편의 잔류물을 줄일 수 있었다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.316-316
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• 2008

Using an evaporation method, $SiO_2$ was deposited as a buffer layer between a flexible PET substrate and a ITO film deposited by DC magnetron sputtering and electro-optical properties were investigated with thickness variance of $SiO_2$ layers. After coating a $SiO_2$ layer and a ITO film, the ITO/$SiO_2$/PET was heated up to $200^{\circ}C$ and the resistivity and the transmittance were measured by hall effect measurement system and UV/VIS/NIR spectroscopy. As a result of depositing a $SiO_2$ buffer layer, the resistivity increased and the transmittance and adhesion property were enhanced than ITO films with no buffer layers and the resistivity was lowered as $SiO_2$ thickness increased from 50 $\AA$ to 100 $\AA$. It was found that the transmittance was independent of annealing temperature variance in $150^{\circ}C{\sim}200^{\circ}C$ and the resistivity decreased as the temperature increased and especially decreasing rate of the resistivity was higher as the buffer layer thickness was thinner. So under optimized depositing of $SiO_2$ buffer layers and post-annealing of ITO/$SiO_2$/PET, ITO films with enhanced adhesion, electro-optical properties can obtained.

• Korean Journal of Materials Research
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• v.21 no.5
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• pp.255-262
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• 2011

This paper has relatively high technical standard and experimental skill. The fabrication of TCO film with high transparency, low resistance and low chromaticity require exact control of several competing factors. This paper has resolved these problems reasonably well, thus recommended for publication. Indium tin oxide(ITO) thin films were by D.C. magnetron roll-to-roll sputter system utilizing ITO and $SiO_2$ targets of ITO and $SiO_2$. In this experiment, the effect of D.C. power, winding speed, and oxygen flow rate on electrical and optical properties of ITO thin films were investigated from the view point of sheet resistance, transmittance, and chromaticity($b^*$). The deposition of $SiO_2$ was performed with RF power of 400W, Ar gas of 50 sccm and the deposition of ITO, DC power of 600W, Ar gas of 50 sccm, $O^2$ gas of 0.2 sccm, and winding speed of 0.56m/min. High quality ITO thin films without $SiO_2$ layer had chromaticity of 2.87, sheet resistivity of 400 ohm/square, and transmittance of 88% and $SiO_2$-doped ITO Thin film with chromaticity of 2.01, sheet resistivity of 709 ohm/square, and transmittance of more than 90% were obtained. As a result, $SiO_2$ was coated on PET before deposition of ITO, their chromaticity($b^*$) and transmittance were better than previous results of ITO films. These results show that coating of $SiO_2$ induced arising chromaticity($b^*$) and transmittance. If the thickness of $SiO_2$ is controlled, sheet resistance value of ITO film will be expected to be better for touch screen. A four point probe and spectrophotometer are used to investigate the properties of ITO thin films.

• Transactions on Electrical and Electronic Materials
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• v.16 no.1
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• pp.29-33
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• 2015

This paper presents the results of the optical characteristics of ITO thin film with different buffer layer thicknesses of $SiO_2$ and $Nb_2O_5$ for touch sensor application. $SiO_2$ and $Nb_2O_5$ buffer layers were deposited using RF magnetron sputtering equipment. The buffer layers were inserted between glass and ITO layers. In order to compare with the experimental results, the Essential Macleod Program (EMP) was adopted. Based on EMP simulation, the [$Nb_2O_5{\mid}SiO_2{\mid}ITO$] multi-layered thin film exhibited high transmittance of more than 85% in the visible region. The actual experimental results also showed transmittance of more than 85% in the visible region, indicating that the simulated results were well matched with the experimental results. The sheet resistance of ITO based film was about $340{\Omega}/sq$. The surface roughness maintained a relatively small value within the range of 0.1~0.4 nm when using the $Nb_2O_5$ and $SiO_2$ buffer layers.

• Journal of the Korean Ceramic Society
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• v.38 no.1
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• pp.15-21
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• 2001

전자파 차폐 및 반사방지용으로 사용되는 SiO$_2$/ITO 이층박막의 전기적 특성에 미치는 전이금속이온의 영향에 대해 고찰하고 전자파 차폐이론식으로부터 박막의 전도특성에 모사하여 효과적인 전자파 차폐효과를 얻기 위한 전도막을 설계하고자 하였다. ITO 상층부에 전이금속염을 첨가한 실리카 복합졸을 코팅하여 SiO$_2$/ITO 이층막을 제조한 결과 최저 표면저항치를 나타내는 첨가량은 전이금속의 종류에 따라 차이를 보이지만 Sn 및 Zn이 첨가된 졸로부터 형성된 박막은 $10^{5}$Ω/$\square$ 이하의 낮은 저항치를 보였으며 가장 안정된 표면저하을 나타내었다. 또한 전자파 차폐효과와 전도박막의 표면저항을 차폐이론식으로부터 모사한 결과 Zn과 Sn의 전이금속염이 첨가된 SiO$_2$/ITO 투명전도막은 TCO99에서 정한 전자파 차폐기준에 부합하였다.다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.5
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• pp.986-991
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• 2016

In this study, we prepared ITO thin films on $Nb_2O_5/SiO_2$ double buffer layer using DC magnetron sputtering method and investigated electrical and optical properties with various substrate temperatures (room temperature ~ $400^{\circ}C$). The resistivity showed a decreasing tendency, because crystallinity has been improved due to the enlarged grain size with increasing substrate temperature. ITO thin film deposited at $400^{\circ}C$ showed the most excellent value of resistivity and sheet resistance as $3.03{\times}10^{-4}{\Omega}{\cdot}cm$, $86.6{\Omega}/sq.$, respectively. In results of optical properties, average transmittance was increased but chromaticity ($b^*$) was decreased in visible light region (400~800nm) with increasing substrate temperature. Average transmittance and chromaticity ($b^*$) of ITO thin film deposited at $400^{\circ}C$ exhibited significantly improved results as 85.8% and 2.13 compared to 82.8% and 4.56 of the ITO thin film without buffer layer. Finally, we found that ITO thin film introduced $Nb_2O_5/SiO_2$ double buffer layer has a remarkably improved optical property such as transmittance and chromaticity due to the index matching effect.