• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.979-982
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• 2008

We studied hybrid passivation using parylene-C, metal, photoacyl and indium zinc oxide for pentacene OTFT to assure stability in subthreshold region. After the passivation, the changes in S and $V_{on}$ of OTFT were negligible and $I_{off}$ maintained its initial value of ${\sim}10^{-12}$ A. Therefore, the hybrid passivation is suitable for practical applications based on OTFT.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1453-1456
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• 2009

Transparent sol-gel hybrid dielectric material (hybrimer) coating films were fabricated by spin coating and photo or thermal curing of sol-gel derived oligosiloxane resins. Hybrimer coating films are suitable as the passivation layer of TFT in AMLCD due to low dielectric constant, small loss tangent, low leakage current density, high transmittance and thermal stability.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.996-998
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• 2004

In this study, we tested parylene as the passivation layer for flexible organic light emitting diodes (FOLEDs).Parylene as passivtion layer has several advantages which are good optical transparent and low moisture penetration. For more an effective passivation of FOLEDs, we suggest hybrid passivation layer with parylene and silicon oxide. We compared electrical properties and stability of the device with and without passivation layer. The lifetime of FOLED with hybrid passivation layer was increased over three times than that of non-passivated of FOLED.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.256-256
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• 2012

Oxide semiconductors such as zinc tin oxide (ZTO) or indium gallium zinc oxide (IGZO) have attracted a lot of research interest owing to their high potential for application as thin film transistors (TFTs) [1,2]. However, the instability of oxide TFTs remains as an obstacle to overcome for practical applications to electronic devices. Several studies have reported that the electrical characteristics of ZnO-based transistors are very sensitive to oxygen, hydrogen, and water [3,4,5]. To improve the reliability issue for the amorphous InGaZnO (a-IGZO) thin-film transistor, back channel passivation layer is essential for the long term bias stability. In this study, we investigated the instability of amorphous indium-gallium-zinc-oxide (IGZO) thin film transistors (TFTs) by the back channel contaminations. The effect of back channel contaminations (humidity or oxygen) on oxide transistor is of importance because it might affect the transistor performance. To remove this environmental condition, we performed vacuum seasoning before the deposition of hybrid passivation layer and acquired improved stability. It was found that vacuum seasoning can remove the back channel contamination if a-IGZO film. Therefore, to achieve highly stable oxide TFTs we suggest that adsorbed chemical gas molecules have to be eliminated from the back-channel prior to forming the passivation layers.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.269-270
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• 2005

A hybrid passivation method using parylene and silicon dioxide combination layer for a flexible organic light emitting diode (FOLED) was applied on a polycarbonate substrate. A parylene coating by vapor polymerization method is a highly effective passivation process for the FOLED, and it applies all top surface and the edges of the FOLED device. In order to minimize the permeation of moisture and oxygen from the top surface of the device, an additional layer of silicon dioxide was deposited over the parylene coated layer. It was found that the water vapor transmittance rate (WVTR) of parylene (15 m-in-thickness) / SiO2 (0.3$\mu$m-in-thickness) combination layers deposited on polycarbonate film was decreased under the value of 10-3 g/m2day. The FOLED with the hybrid passivation showed remarkably longer lifetime characteristics in the ambient conditions than the non-passivated FOLED. The lifetime of the passivated FOLED was 400 hours and it was more than ten times over the lifetime of the convectional non-passivated FOLED.

• Journal of the Korean institute of surface engineering
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• v.43 no.6
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• pp.272-277
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• 2010

We investigated the life time characteristics of OLED device with aluminium oxide ($AlO_x$) passivation film on glass substrate and polyethylene terephthalate (PET) substrate by RF magnetron sputtering for the transparent barrier film applied to flexible OLED device. Basic buffer layer was determined as $Alq_3$(500 nm)-LiF(300 nm)-Al(1200 nm), and the most suitable aluminium oxide ($AlO_x$) film have been formed when the partial volume ratio of oxygen was 20% and the sputtering power was 100 watt and the minimum thickness of buffer was $2\;{\mu}m$. $AlO_x$/epoxy hybrid film was also used as a effective passivation layer for the purpose of improving life time characteristics of OLED devices with the glass substrate and the plastic substrate. Besides, the simultaneous deposition of $AlO_x$/epoxy film on back side of PET could result in better improvement of life time.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1779-1783
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• 2006

The hybrid thin-film (HTF) passivation layer composed of the UV curable acrylate layer and MS-31 (MgO:SiO2=3:1wt%) layer was adopted in organic light emitting diode (OLED) to protect organic light emitting materials from penetrations of oxygen and water vapors. The moisture resistance of the deposited HTF layer was measured by the water vapor transmission rate (WVTR). The results showed that the HTF layer possessed a very low WVTR value of lower than $0.007g/m^2$ per day at $37.8^{\circ}C$ and 100% RH. Therefore, the HTF on the OLED was found to be very effective in protect what from the penetrations of oxygen and moisture.

• Journal of the Korean institute of surface engineering
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• v.45 no.1
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• pp.20-24
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• 2012

Multilayer passivation film on OLED with organic/inorganic hybrid structure as to diminish the thermal stress and expansion was researched to protect device from the direct damage of $O_2$ and $H_2O$ and improve life time characteristics. Red OLED doped with 1 vol.% Rubrene in $Alq_3$ was used as a basic device. The films consist of ITO(150 nm)/ELM200_HIL(50 nm)/ELM002_HTL(30 nm)/$Alq_3$: 1 vol.% Rubrene(30 nm)/$Alq_3$(30 nm) and LiF(0.7 nm)/Al(100 nm) which were formed in that order. Using LiF/$SiN_x$ as a buffer layer was determined because it significantly improved life time characteristics without suffering damage in the process of forming passivation film. Multilayer passivation film on buffer layer didn't produce much change in current efficiency, while the half life time at 1,000 $cd/m^2$ of OLED/LiF/$SiN_x$/E1/$SiN_x$ was 710 hours which showed about 1.5 times longer than OLED/LiF/$SiN_x$/E1 with 498 hours. futhermore, OLED/LiF/$SiN_x$/E1/$SiN_x$/E1/$SiN_x$ with 1301 hours showed about twice than OLED/LiF/$SiN_x$/E1/$SiN_x$ which demonstrated that superior characteristics of life time was obtained in multilayer passivation film. Through the above result, it was suggested using LiF/$SiN_x$ as a buffer layer could reduce the damage from the difference of thermal expansion coefficient in OLED with protective films, and epoxy layer in multilayer passivation film could function like a buffer between $SiN_x$ inorganic layers with relatively large thermal stress.

• Journal of the Korean institute of surface engineering
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• v.42 no.6
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• pp.287-293
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• 2009

The passivation films with epoxy layer on LiF, $SiN_x$ and LiF/$SiN_x$ inorganic layer were fabricated on OLED to protect device from the direct damage of $O_2$ and $H_2O$ and to apply for a buffer layer between OLED device and passivation multi-layer with organic/inorganic hybrid structure as to diminish the thermal stress and expansion. Red OLED doped with 1 vol.% Rubrene in $Alq_3$ was used as a basic device. The device structure was multi-layer of ITO(150 nm) / ELM200_HIL(50 nm) / ELM002_HTL(30 nm) / $Alq_3$: 1 vol.% Rubrene(30 nm) / $Alq_3$(30 nm) / LiF(0.7 nm) / Al(100 nm). LiF/epoxy applied as a protective layer didn't contribute to the improvement of life time. While in case of $SiN_x$/epoxy, damage was done in the passivation process because of difference in heat expansion between films which could occur during the formation of epoxy film. Using LiF/$SiN_x$/epoxy improved lifetime significantly without suffering damage in the process of forming films, therefore, the best structure of passivation film with inorganic/epoxy layers was LiF/$SiN_x$/E1.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.04a
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• pp.78-80
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• 2006

The hybrid thin-film (HTF) passivation layer composed of the Ultra Violet (UV) curable acrylate layer and MS-31 (MgO:$SiO_2$=3:1wt%) layer was adopted in organic light emitting device (OLEO) to protect organic light emitting materials from penetrations of oxygen and water vapors. The results showed that the HTF layer possessed a very low WVTR value of lower than $0.007gm/m^{2+}day$ at $37.8^{\circ}C$ and 100% RH. This value was within the limited range of the sensitivity of WVTR measurements. And the lifetime of the HTF passivated device became almost three times longer than that of the bare device. The HTF on the OLEO was found to be very effective in protect what from the penetrations of oxygen and moisture.