• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.17 no.3
• /
• pp.51-58
• /
• 2018

In this paper, the organic material Poly(methyl methacrylate) PMMA is used with inorganic $Al_2O_3$ to fabricate organic-inorganic multilayer barrier thin films. The organic thin films are developed using a roll-to-roll electrohydrodynamic atomization system, whereas the inorganic are grown using a roll-to-roll low-temperature atmospheric pressure atomic layer deposition system. For the first time, these two technologies are used together to develop organic-inorganic multilayer barrier thin films in atmospheric condition. The films are grown under optimized parameters and classified into three classes based on the layer structures, when the total thickness of the barrier is maintained at ~ 160 nm. All classes of barriers show good morphological, optical and chemical properties. The $Al_2O_3$ films with a low average arithmetic roughness of 1.58 nm conceal the non-uniformity and irregularities in PMMA thin films with a roughness of 5.20 nm. All classes of barriers show a notably good optical transmission of ~ 85 %. The hybrid organic-inorganic barriers show water vapor and oxygen permeation in the range of ${\sim}3.2{\times}10^{-2}g/m^2/day$ and $0.015cc/m^2/day$ at $23^{\circ}C$ and 100% relative humidity. It has been confirmed that it can be mass-produced and used as a low-cost barrier thin film in various printing electronic devices.

• Journal of the Semiconductor & Display Technology
• /
• v.16 no.4
• /
• pp.1-4
• /
• 2017

Encapsulation of organic based devices is essential issue due to easy deterioration of organic material by water vapor. Atomic layer deposition (ALD) is a promising solution because of its low temperature deposition and quality of the deposited film. Moisture permeation has a mechanism to pass through defects, Thin Film Encapsulation using inorganic / organic / inorganic hybrid film has been used as promising technology. $Al_2O_3$ / Polymer / $Al_2O_3$ multilayer film has shown excellent environmental protection characteristics despite of thin thicknesses of the films.

• Journal of the Semiconductor & Display Technology
• /
• v.16 no.1
• /
• pp.1-5
• /
• 2017

Encapsulation of organic based devices is essential issue due to easy deterioration of organic material by water vapor. Thin layer of encapsulation film is required to preserve transparency yet protecting materials in it. Atomic layer deposition(ALD) is a promising solution because of its low temperature deposition and quality of the deposited film. $Al_2O_3$ or $Al_2O_3/TiO_2/Al_2O_3$ multilayer film has shown excellent environmental protection characteristics despite of thin thicknesses of the films. $Al_2O_3/TiO_2/Al_2O_3$ multilayer and 1.5 dyad layer of $Al_2O_3/polymer/Al_2O_3$ deposited by ALD was measured to have water vapor transmittance rate(WVTR) well below the detection limit($5.0{\times}10^{-5}g/m^2day$) of MOCON Aquatran 2 equipment.

• 정보저장시스템학회:학술대회논문집
• /
• 2005.10a
• /
• pp.254-259
• /
• 2005

In this study, measurement of thermal conductivity of multilayer thin dielectric film has been conducted via differential 3$\omega$ method. Also, verification of differential 3$\omega$ method has been accomplished with various proposed criteria. The target film for measurement is 300 nm silicon dioxide and this thin film is covered with various thicknesses of upper protective layer. The upper protective layer is inserted between the target film and the heater line for purpose of electrical insulator or anti-oxidation barrier since the target film may be a good electrical conductor or a well-oxidizing material. However, the verification of differential 3$\omega$ method has not been conducted. Thus we have shown that the measurement of thermal conductivity of thin films with upper protective layer via differential 3$\omega$ method is verified to be reliable as long as the proposed preconditions are satisfied. Experimental results show that the experimental errors tend to increase with aspect ratio between upper protective layer thickness and width of the heater line due to heat spreading effect.

• Transactions of the Society of Information Storage Systems
• /
• v.2 no.1
• /
• pp.85-90
• /
• 2006

In this study, measurement of thermal conductivity of multilayer thin dielectric film has been conducted via differential $3\omega$ method. Also, verification of differential $3\omega$ method has been accomplished with various proposed criteria. The target film for the measurement is 300 nm thick silicon dioxide which is covered with upper protective layer of various thicknesses. The upper protective layer is inserted between the target film and the heater line for purpose of electrical insulator or anti-oxidation barrier since the target film may be a good electrical conductor or a well-oxidizing material. Since the verification of differential $3\omega$ method has not been conducted yet, we have shown that the measurement of thermal conductivity of thin films with upper protective layer via differential $3\omega$ method is verified to be reliable as long as the proposed preconditions of the samples are satisfied. Experimental results show that the experimental errors tend to increase with aspect ratio between thickness of the upper protective layer and width of the heater line due to heat spreading effect.

• Journal of Sensor Science and Technology
• /
• v.22 no.2
• /
• pp.105-110
• /
• 2013

We fabricated an a-IGZO thin film transistor (TFT) with AZO/Ag/AZO transparent multilayer source/drain contacts by rf magnetron sputtering. a-IGZO TFT with AZO/Ag/AZO multilayer S/D electrodes (W/L = 400/50 ${\mu}m$) showed a subs-threshold swing of 3.78 V/dec, a minimum off-current of $10^{-12}$ A, a threshold voltage of 0.41 V, a field effect mobility of $10.86cm^2/Vs$, and an on/off ratio of $9{\times}10^9$. From the ultraviolet photoemission spectroscopy, it was revealed that the enhanced electrical performance resulted from the lowering of the Schottky barrier between a-IGZO and Ag due to the insertion of an AZO layer and thus the AZO/Ag/AZO multilayer would be very appropriate for a promising S/D contact material for the fabrication of high performance TFTs.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2012.05a
• /
• pp.110.1-110.1
• /
• 2012

Recently, advances in ZnO based oxide semiconductor materials have accelerated the development of thin-film transistors (TFTs), which are the building blocks for active matrix flat-panel displays including liquid crystal displays (LCD) and organic light-emitting diodes (OLED). However, the electrical performances of oxide semiconductors are significantly affected by interactions with the ambient atmosphere. Jeong et al. reported that the channel of the IGZO-TFT is very sensitive to water vapor adsorption. Thus, water vapor passivation layers are necessary for long-term current stability in the operation of the oxide-based TFTs. In the present work, $Al_2O_3$ and $TiO_2$ thin films were deposited on poly ether sulfon (PES) and $SnO_x$-based TFTs by electron cyclotron resonance atomic layer deposition (ECR-ALD). And enhancing the WVTR (water vapor transmission rate) characteristics, barrier layer structure was modified to $Al_2O_3/TiO_2$ layered structure. For example, $Al_2O_3$, $TiO_2$ single layer, $Al_2O_3/TiO_2$ double layer and $Al_2O_3/TiO_2/Al_2O_3/TiO_2$ multilayer were studied for enhancement of water vapor barrier properties. After thin film water vapor barrier deposited on PES substrate and $SnO_x$-based TFT, thin film permeation characteristics were three orders of magnitude smaller than that without water vapor barrier layer of PES substrate, stability of $SnO_x$-based TFT devices were significantly improved. Therefore, the results indicate that $Al_2O_3/TiO_2$ water vapor barrier layers are highly proper for use as a passivation layer in $SnO_x$-based TFT devices.

• Proceedings of the KSME Conference
• /
• 2007.05a
• /
• pp.215-219
• /
• 2007

In this work, the indium zinc oxide (IZO) films had been deposited on the glass substrate coated with the SiO film. Based on a comparative investigation of the IZO monolayer and IZO/SiO multilayer, it is shown that the thickness of SiO film has a great effect on the mechanical properties of the thin films. The AFM images of the IZO thin film included the SiO film were shown smoother surfaces than monolayer. Resistivity was in inverse proportion to Mobility. If it deposited the SiO film on the substrate, the layer of change was generated between two layer(SiO and substrate). The layer of change influenced resistance because of oxygen content was more than the IZO monolayer.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.95-95
• /
• 2014

An OLED(Organic Light-Emitting Diode) device based on the emissive electroluminescent layer a film of organic materials. OLED is used for many electronic devices such as TV, mobile phones, handheld games consoles. ULVAC's mass production systems are indispensable to the manufacturing of OLED device. ULVAC is a manufacturer and worldwide supplier of equipment and vacuum systems for the OLED, LCD, Semiconductor, Electronics, Optical device and related high technology industries. The SMD Series are single-substrate sputtering systems for deposition of films such as metal films and TCO (Transparent Conductive Oxide) films. ULVAC has delivered a large number of these systems not only Organic Evaporating systems but also LTPS CVD systems. The most important technology of thin-film encapsulation (TFE) is preventing moisture($H_2O$) and oxygen permeation into flexible OLED devices. As a polymer substrate does not offer the same barrier performance as glass substrate, the TFE should be developed on both the bottom and top side of the device layers for sufficient lifetimes. This report provides a review of promising thin-film barrier technologies as well as the WVTR(Water Vapor Transmission Rate) properties. Multilayer thin-film deposition technology of organic and inorganic layer is very effective method for increasing barrier performance of OLED device. Gases and water in the organic evaporating system is having a strong influence as impurities to OLED device. CRYO pump is one of the very useful vacuum components to reduce above impurities. There for CRYO pump is faster than conventional TMP exhaust velocity of gases and water. So, we suggest new method to make a good vacuum condition which is CRYO Trap addition on OLED evaporator. Alignment accuracy is one of the key technologies to perform high resolution OLED device. In order to reduce vibration characteristic of CRYO pump, ULVAC has developed low vibration CRYO pumps to achieve high resolution alignment performance between Metal mask and substrate. This report also includes ULVAC's approach for these issues.

• Transactions on Electrical and Electronic Materials
• /
• v.8 no.1
• /
• pp.36-40
• /
• 2007

Inorganic layers, such as SiOxNy and SiOx deposited using plasma sublimation method, were tested as passivation layer for organic thin-film-transistors (OTFTs). OTFTs with bottom-gate and bottom-contact structure were fabricated using pentacene as organic semiconductor and an organic gate insulator. SiOxNy layer gave little change in characteristics of OTFTs, but SiOx layer degraded the performance of OTFTs severely. Inferior barrier properties related to its lower film density, higher water vapor transmission rate (WVTR) and damage due to process environment of oxygen of SiOx film could explain these results. Polyurea and polyvinyl acetates (PVA) were tested as organic passivation layers also. PVA showed good properties as a buffer layer to reduce the damage come from the vacuum deposition process of upper passivation layers. From these results, a multilayer structure with upper SiOxNy film and lower PVA film is expected to be a superior passivation layer for OTFTs.