• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.10
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• pp.1412-1416
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• 2014

We report thin-film organic moisture barriers based on polystyrene(PS) laminates deposition by PECVD for an encapsulation of OLEDs. The organic polystyrene thin-film has the benzene ring structure and high hydrophobic characteristics and it was polymerized by PECVD in dry process. Life time properties of Ca test were obtained 32 minutes at the RF 100W process conditions. From the AFM test, the roughness of multi-layer thin-film was more excellent rather than that of a single-layer thin-film. In addition, 5 layers of the multi-layer film properties were obtained 45 minutes. So that the optical and electrical properties were not affected with these plasma polymerized organic thin-film encapsulation. For life time improvement, the inorganic $Al_2O_3$ thin-film were deposited 5nm using ALD atomic layer deposition. The WVTR(Water Vaper Transmission Rate) value of hybrid thin-film encapsulation in the optimum process conditions was resulted by less than $10-3g/m^2/day$. From the results of experiment, plasma polymerized hybrid encapsulation was suggested as the flexible display applications.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.319-319
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• 2013

Even though the fabrication methods of metal oxide based thin film capacitor have been well established such as RF sputtering, Sol-gel, metal organic chemical vapor deposition (MOCVD), ion beam assisted deposition (IBAD) and pulsed laser deposition (PLD), an applicable capacitor of printed circuit board (PCB) has not realized yet by these methods. Barium Strontium Titanate (BST) and other high-k ceramic oxides are important materials used in integrated passive devices, multi-chip modules (MCM), high-density interconnect, and chip-scale packaging. Thin film multi-layer technology is strongly demanded for having high capacitance (120 nF/$mm^2$). In this study, we suggest novel multi-layer thin film capacitor design and fabrication technology utilized by plasma assisted deposition and photolithography processes. Ba0.6Sr0.4TiO3 (BST) was used for the dielectric material since it has high dielectric constant and low dielectric loss. 5-layered BST and Pt thin films with multi-layer sandwich structures were formed on Pt/Ti/$SiO_2$/Si substrate by RF-magnetron sputtering and DC-sputtering. Pt electrodes and BST layers were patterned to reveal internal electrodes by photolithography. SiO2 passivation layer was deposited by plasma-enhanced chemical vapor deposition (PE-CVD). The passivation layer plays an important role to prevent short connection between the electrodes. It was patterned to create holes for the connection between internal electrodes and external electrodes by reactive-ion etching (RIE). External contact pads were formed by Pt electrodes. The microstructure and dielectric characteristics of the capacitors were investigated by scanning electron microscopy (SEM) and impedance analyzer, respectively. In conclusion, the 0402 sized thin film multi-layer capacitors have been demonstrated, which have capacitance of 10 nF. They are expected to be used for decoupling purpose and have been fabricated with high yield.

• Journal of Ocean Engineering and Technology
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• v.25 no.1
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• pp.39-43
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• 2011

This study has lowered the specific resistance by coating a thin film layer of Ag, playing the role of the electron donor on the ZnO that is used usefully for the transparent conductive oxides. Presently, this study has examined the transmittance and electric characteristics according to the thickness of the Ag thin film layer. Also, this study has observed the transmittance and electric characteristics according to the uppermost ZnO thin film layer of ZnO/Ag/ZnO symmetric film and has conducted the theoretical investigation. In order to observe the transmittance and electric characteristics according to the thickness of the Ag thin film layer and the uppermost ZnO thin film layer, this study conducted the film deposition at room temperature while making use of the DC magnetron sputtering system. In order to see the changes in the thickness of the Ag thin film layer, this study coated a thin film while increasing by 4nm; and, in order to see the changes in the thickness of uppermost ZnO thin film layer, it performed the thin film coating by increasing by 5nm. From the experimental result, the researchers observed that the best transmittance could be obtained when the thickness of the Ag thin film layer was 8nm, but the resistance and mobility increased as the thickness got larger. On the other hand, when the thickness of the uppermost ZnO thin film layer was 20nm, the experiment yielded the best transmittance with excellent electric characteristics. Also, when compared the ZnO/Ag asymmetric film with the ZnO/Ag/ZnO symmetric film, the ZnO/Ag asymmetric film showed better transmittance and electric characteristics.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.395-395
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• 2012

We fabricate organic-inorganic hybrid thin film for the purpose of encapsulation by molecular layer deposition (MLD) using Trimethylaluminium (TMA) and Adipoyl Chloride (AC). Ellipsometry was employed to verify self limiting reaction of ALD. Linear relationship between number of cycle and thickness was obtained. We found that desirable organic thin film fabrication is possible by MLD surface reaction in nanoscale. Purging was carried out after dosing of each precursor to form monolayer in each sequence. We also confirmed roughness of the organic thin film by atomic force microscopy. We deposit TMA and AC at $70^{\circ}C$ and that 1.78A root mean square was obtained which indicates that uniform organic thin film was formed. We confirmed precursor's functional group by IR spectrum. We calculated WVTR of organic-inorganic hybrid super-lattice epitaxial layer using Ca test. WVTR indicates superlattice film can be possibly use as encapsulation in flexible devices.

• Journal of Information Display
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• v.5 no.3
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• pp.30-34
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• 2004

Fabrications of barrier layer on a polyethersulfon (PES) film and OLED based on a plastic substrate by atomic layer deposition (ALD) have been carried out. Simultaneous deposition of 30 nm of $AlO_x$ film on both sides of PES film gave film MOCON value of 0.0615 g/$m^2$/day (@38$^{\circ}C$, 100 % R.H.). Moreover, the double layer of 200 urn $SiN_x$ film deposited by PECVD and 20 nm of $AlO_x$ film by ALD resulted in the MOCON value lower than the detection limit of MOCON. The OLED encapsulation performance of the double layer have been investigated using the OLED structure of ITO/MTDATA(20 nm)/NPD(40 nm)/AlQ(60 nm)/LiF(1 nm)/Al(75 nm) based on the plastic substrate. Preliminary life time to 91 % of initial luminance (1300 cd/$m^2$) was 260 hours for the OLED encapsulated with 100 nm of PECVD deposited $SiN_x$/30 nm of ALD deposited $AlO_x$.

• Journal of information and communication convergence engineering
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• v.4 no.4
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• pp.158-161
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• 2006

[ $Bi_2Sr_2Ca_nCu_{n+1}O_y(n{\geq}0)$ ] thin film is fabricatedvia two different processes using an ion beam sputtering method i.e. co-deposition and layer-by-layer deposition. A single phase of Bi2212 can be fabricated via the co-deposition process. While it cannot be obtained by the layer-by-layer process. Ultra-low growth rate in our ion beam sputtering system brings out the difference in Bi element adsorption between the two processes and results in only 30% adsorption against total incident Bi amount by layer-by-layer deposition, in contrast to enough Bi adsorption by co-deposition.

• Korea-Australia Rheology Journal
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• v.19 no.1
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• pp.27-33
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• 2007

The co-extrusion of multi-layer films has been studied with the focus on its process stability. As in the single-layer film casting process, the productivity of the industrially important multi-layer film casting and the quality of thus produced films have often been hampered by various instabilities occurring in the process including draw resonance, a supercritical Hopfbifurcation instability, frequently encountered when the draw ratio is raised beyond a certain critical value. In this study, this draw resonance instability along with the neck-in of the film width has been investigated for a three-layer film casting using a varying width non-isothermal 1-D model of the system with Phan-Thien and Tanner (PTT) constitutive equation known for its robustness in portraying extensional deformation processes. The effects of various process conditions, e.g., the aspect ratio, the thickness ratio of the individual film layers, and cooling of the process, on the stability have been examined through the nonlinear stability analysis.

• Transactions on Electrical and Electronic Materials
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• v.13 no.4
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• pp.185-187
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• 2012

Ga doped ZnO (GZO)/copper (Cu) bi-layered film was deposited on glass substrate by RF and DC magnetron sputtering and then the effect of the Cu bottom layer on the optical, electrical and structural properties of GZO films were considered. As-deposited 100 nm thick GZO films had an optical transmittance of 82% in the visible wavelength region and a sheet resistance of 4139 ${\Omega}/{\Box}$, while the GZO/Cu film had optical and electrical properties that were influenced by the Cu bottom layer. GZO films with 5 nm thick Cu film show the lower sheet resistance of 268 ${\Omega}/{\Box}$ and an optical transmittance of 65% due to increased optical absorption by the Cu metallic bottom layer. Based on the figure of merit, it can be concluded that the thin Cu bottom layer effectively increases the performance of GZO films as a transparent and conducting electrode without intentional substrate heating or a post deposition annealing process.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.132-132
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• 2011

The sheet resistance (Rs) of undoped GaN films on AlN/c-plane sapphire substrate was investigated in which the AlN films were grown by R. F. magetron sputtering method. The Rs was strongly dependent on the AlN layer thickness and semi-insulating behavior was observed. To clarify the effect of crystalline property on Rs, the crystal structure of the GaN films has been studied using x-ray scattering and transmission electron microscopy. A compressive strain was introduced by the presence of AlN nucleation layer (NL) and was gradually relaxed as increasing AlN NL thickness. This relaxation produced more threading dislocations (TD) of edge-type. Moreover, the surface morphology of the GaN film was changed at thicker AlN layer condition, which was originated by the crossover from planar to island grains of AlN. Thus, rough surface might produce more dislocations. The edge and mixed dislocations propagating from the interface between the GaN film and the AlN buffer layer affected the electric resistance of GaN film.

• Journal of the Korean institute of surface engineering
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• v.50 no.5
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• pp.345-351
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• 2017

A double-layered anti-reflective coating with hydrophilic/abrasion-resistant properties was studied using anatase titanium dioxide($TiO_2$) and silicon oxycarbide($SiO_xC_y$) thin film. $TiO_2$ and $SiO_xC_y$ thin films were sequentially deposited on a glass substrate by DC sputtering and PECVD, respectively. The optical properties were measured by UV-Vis-NIR spectrophotometer. The abrasion-resistance and the hydrophilicity were observed by a taber abrasion tester and a contact angle analyzer, respectively. The $TiO_2/SiO_xC_y$ double-layer thin film had an average transmittance of 91.3%, which was improved by 10% in the visible light region (400 to 800 nm) than that of the $TiO_2$ single-layer thin film. The contact angle of $TiO_2/SiO_xC_y$ film was $6.9^{\circ}$ right after UV exposure. After 9 days from the exposure, the contact angle was $10.2^{\circ}$, which was $33^{\circ}$ lower than that of the $TiO_2$ single-layer film. By the abrasion test, $SiO_xC_y$ film showed a superior abrasion-resistance to the $TiO_2$ film. Consequently, the $TiO_2/SiO_xC_y$ double-layer film has achieved superior anti-reflection, hydrophilicity, and abrasion resistance over the $TiO_2$ or $SiO_xC_y$ single-layer film.