• Journal of the Semiconductor & Display Technology
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• v.21 no.2
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• pp.11-14
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• 2022

In this work, we evaluated the Al₂O₃ film, which was deposited by atomic layer deposition, degraded by exposure to harsh environments. The Al₂O₃ films deposited by atomic layer deposition have long been used as a gas diffusion barrier that satisfies barrier requirements for device reliability. To investigate the barrier and mechanical performance of the Al₂O₃ film with increasing temperature and relative humidity, the properties of the degraded Al₂O₃ film exposed to the harsh environment were evaluated using electrical calcium test and tensile test. As a result, the water vapor transmission rate of Al₂O₃ films stored in harsh environments has fallen to a level that is difficult to utilize as a barrier film. Through water vapor transmission rate measurements, it can be seen that the water vapor transmission rate changes can be significant, and the environment-induced degradation is fatal to the Al₂O₃ thin films. In addition, the surface roughness and porosity of the degraded Al₂O₃ are significantly increased as the environment becomes severer. the degradation of elongation is caused by the stress concentration at valleys of rough surface and pores generated by the harsh environment. Becaused the harsh envronment-induced degradation convert amorphous Al₂O₃ to crystalline structure, these encapsulation properties of the Al₂O₃ film was easily degraded.

• Korean Journal of Materials Research
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• v.26 no.8
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• pp.430-437
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• 2016

Aluminum oxide ($Al_2O_3$) thin films were grown by atomic layer deposition (ALD) using a new Al metalorganic precursor, dimethyl aluminum sec-butoxide ($C_{12}H_{30}Al_2O_2$), and water vapor ($H_2O$) as the reactant at deposition temperatures ranging from 150 to $300^{\circ}C$. The ALD process showed typical self-limited film growth with precursor and reactant pulsing time at $250^{\circ}C$; the growth rate was 0.095 nm/cycle, with no incubation cycle. This is relatively lower and more controllable than the growth rate in the typical $ALD-Al_2O_3$ process, which uses trimethyl aluminum (TMA) and shows a growth rate of 0.11 nm/cycle. The as-deposited $ALD-Al_2O_3$ film was amorphous; X-ray diffraction and transmission electron microscopy confirmed that its amorphous state was maintained even after annealing at $1000^{\circ}C$. The refractive index of the $ALD-Al_2O_3$ films ranged from 1.45 to 1.67; these values were dependent on the deposition temperature. X-ray photoelectron spectroscopy showed that the $ALD-Al_2O_3$ films deposited at $250^{\circ}C$ were stoichiometric, with no carbon impurity. The step coverage of the $ALD-Al_2O_3$ film was perfect, at approximately 100%, at the dual trench structure, with an aspect ratio of approximately 6.3 (top opening size of 40 nm). With capacitance-voltage measurements of the $Al/ALD-Al_2O_3/p-Si$ structure, the dielectric constant of the $ALD-Al_2O_3$ films deposited at $250^{\circ}C$ was determined to be ~8.1, with a leakage current density on the order of $10^{-8}A/cm^2$ at 1 V.

• Journal of the Korean Ceramic Society
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• v.33 no.9
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• pp.985-994
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• 1996

The initiation and growth of $\alpha$-Al2O3/metal composites by the directed oxidation of molten commercial AlZnMg-alloy at 1223-1423K were investigated. Spontaneous bulk growth did not occur on the alloy alone. but the uniform initiation and growth of the composite were obtained by putting a thin layer of SiO2 particles on the surface of the alloy. Without SiO2 the external surface of the oxide layer was convered by MgO and MgAl2O4. But with the SiO2 reaction initiate the porous ZnO layers were found on the growth surface. The higher process temperature yielded a lower metal content. The oxidation product of $\alpha$-Al2O3 was found to be oriented with c-axis parallel to th growth direction. The growth rates increased with temperature and the apparent activation energy was 111.8 kJ/mol.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.02a
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• pp.287-290
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• 2003

For microwave device applications, c-axis oriented high temperature superconducting YBa$_2$Cu$_3$O$_{7-{\delta}}$ (HTS-YBCO) epitaxial thin films on the r-cut sapphire substrate(Al$_2$O$_3$) were prepared. In order to reduce the lattice mismatch with a substrate and to enhance the crystallity of HTS thin films, CeO$_2$ buffer layer on the r-cut sapphire substrate was grown by the RF-magnetron sputtering. The YBCO films on the CeO$_2$ buffer layer were deposited using the pulsed-laser deposition (PLD) method. These HTS YBCO /CeO$_2$/Al$_2$O$_3$ multilayer thin films(30 $\times$ 30 mm$^2$) routinely exhibited a critical temperature(T$_{c}$) of 89 K from the R-T measurement. Using HTS YBCO/CeO$_2$ /Al$_2$O$_3$ multilayer thin film. We fabricated and characterized the microwave passive devices (planar type filters) with cryopack-age such as the coupled -line type low-pass filter (LPF) and the open-loop meander type bandpass filter (BPF).filter (BPF).).

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.359-361
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• 2003

Nano-porous alumina was investigated as a protecting layer in an AC Plasma Display Panel. A 2 ${\mu}m$ thick nano-porous $Al_2O_3$ layer inserted with MgO was formed on the dielectric layer instead of the conventional 500 nm-thick MgO thin film. Both nano-porous $Al_2O_3$layer and inserted MgO were prepared by wet process. The luminance and luminous efficiency of 3-inch test panel adopting nano-porous $Al_2O_3$ was higher than that of the conventional PDP.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.394-394
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• 2012

We fabricated organic-inorganic superlattice films using molecular layer deposition (MLD) and atomic layer deposition (ALD). The MLD is a gas phase process in the vacuum like to atomic layer deposition (ALD) and also relies on a self-terminating surface reaction of organic precursor which results in the formation of a monolayer in each sequence. In the MLD process, 'Alucone' is very famous organic thin film fabricated using MLD. Alucone layers were grown by repeated sequential surface reactions of trimethylaluminum and ethylene glycol at substrate temperature of $80^{\circ}C$. In addition, we developed UV-assisted $Al_2O_3$ with gas diffusion barrier property better than typical $Al_2O_3$. The UV light was very effective to obtain defect-free, high quality $Al_2O_3$ thin film which is determined by water vapor transmission rate (WVTR). Ellipsometry analysis showed a self-limiting surface reaction process and linear growth of each organic, inorganic film. Composition of the organic films was confirmed by infrared (IR) spectroscopy. Ultra-violet (UV) spectroscopy was employed to measure transparency of the organic-inorganic superlattice films. WVTR is calculated by Ca test. Organic-inorganic superlattice films using UV-assisted $Al_2O_3$ and alucone have possible use in gas diffusion barrier for OLED.

• Journal of the Semiconductor & Display Technology
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• v.22 no.1
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• pp.23-27
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• 2023

Organic light-emitting diode(OLED) is very thin organic films which are hundreds of nanometers. Unlike bottom-emission OLED(BEOLED), top-emission OLED(TEOLED) emits light out the front, opaque moisture absorbents or metal foils can't be used to prevent moisture and oxygen. And it is difficult to have flexible characteristics with glass encapsulation, so thin film encapsulation which can compensate for those two disadvantages is mainly used. In this study, Al₂O₃ thin films by atomic layer deposition(ALD) were examined by changing the argon gas purge flow rate and we applied this Al₂O₃ thin films to the encapsulation of TEOLED. Ag / ITO / N,N'-Di-[(1-naphthyl)-N,N'-diphenyl]-1,1'-biphenyl-4,4'-diamine / tris-(8-hydroxyquinoline) aluminum/ LiF / Mg:Ag (1:9) were used to fabricate OLED device. The characteristics such as brightness, current density, and power efficiency are compared. And it was confirmed that with a thickness of 40 nm Al₂O₃ thin film encapsulation process did not affect OLED properties. And it was enough to maintain a proper OLED operation for about 9 hours.

• Korean Journal of Materials Research
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• v.12 no.8
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• pp.676-681
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• 2002

Microstructure, mechanical properties, and oxidation resistance of TiAIN thin films deposited on quenched and tempered STD61 tool steel by arc ion plating were studied using XRD, XPS and micro-balance. The TiAIN film was grown with the (200) orientation. The grain size of TiAIN thin film decreased with increasing Al contents, while chemical binding energy increased with Al contents. When hard coating films were oxidized at $850^{\circ}C$ in air, oxidation resistance of both TiN and TiCN films became relatively lower since the surface of films formed non-protective film such as $TiO_2$. However, oxidation resistance of TiAIN film was excellent because its surface formed protective layer such as $_A12$$O_3$ and $_Al2$$Ti_{7}$$O_{15}$, which suppressed oxygen intrusion.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.319-320
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• 2009

In this study, high-quality Al-N doped p-type ZnO thin films were deposited on n-type Si (100) wafer or Si coated with buffer layer by DC magnetron sputtering in the mixture of $N_2$ and $O_2$ gas. The target was ceramic ZnO mixed with $Al_2O_3$ (2 wt%). The p-type ZnO thin film showed higher carrier concentration $2.93\times10^{17}cm^{-3}$, lower resistivity of $5.349\;{\Omega}cm$ and mobility of $3.99\;cm^2V^{-1}S^{-1}$, respectively. According to PL spectrum, the Al donor energy level depth ($E_d$) of Al-N codoped p-type ZnO film was reduced to about 51 meV, and the N acceptor energy level depth ($E_a$) was reduced to 63 meV, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.292-292
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• 2007

To apply PDP panel, Soda lime glass(SLG) is cheeper than Non-alkali glass and PD-200 glass but has problems such as low strain temperature and ion diffusion by alkali metal oxide. In this paper suggest the methode that prohibits ion diffusion by deposing barrier layer on SLG. Indium thin oxide(ITO) thin films and barrier layers were prepared on SLG substrate by Rf-magnetron sputtering. These films show a high electrical resistivity and rough uniformity as compared with PD-200 glass due to the alkali ion from the SLG on diffuse to the ITO film by the heat treatment. However these properties can be improved by introducing a barrier layer of $SiO_2\;or\;Al_2O_3$ between ITO film and SLG substrate. The characteristics of films were examined by the 4-point probe, SEM, UV-VIS spectrometer, and X-ray diffraction. GDS analysis confirmed that barrier layer inhibited Na and Ka ion diffusion from SLG. Especially ITO films deposited on the $Al_2O_3$ barrier layer had higher properties than those deposited on the $SiO_2$ barrier layer.