• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.166.2-166.2
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• 2014

In this work, we demonstrated a facile and effective method for deposition of metal tetraphenylporphyrin (MTPP) thin film by a combined a thermal evaporation (TE) and atomic layer deposition (ALD). For the deposition of Zn-TPP thin film, Tetraphenylporphyrin (TPP) and diethyl zinc (DEZ) were used as organic and inorganic materials, respectively. Optimum conditions for the deposition of Zn-TPP thin film were established systematically: (1) the exposure time of DEZ as inorganic precursor and (2) the substrate temperature were adjusted, respectively. As a result, we verified that the surface reaction between organic semiconductor (TPP) and metal atom (Zn) was ALD process. In addition, we calculated activation energy by using Arrhenius equation for the substrate temperature versus area change rate of pyrrolic nitrogen. The surface and interface reactions between TPP with Zn were investigated by X-ray photoelectron spectroscopy, Raman spectroscopy, UV-vis spectroscopy, and scanning electron microscopy. These results show a facile and well-controllable fabrication technique for the metal-organic thin film for future electronic applications.

• Journal of the Korean institute of surface engineering
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• v.22 no.3
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• pp.109-117
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• 1989

The effect of heft treatment on the characteristic properties of insulation layer is studied for two kinds of non-oriented silicon steels, which were insulation-coates with various kinds of inorganic and inorganic-organic complex coating solutions. In addition, how the carbon contained in the insulation layer would affect the carbon content and the magnetic properties of the steel substrates is examined. Lower temperature heat treftment ($480^{\circ}C$ for 0.5hr) is found to render morw favorable surface qualities, wheras higher temperature heat treatment ($790^{\circ}C$ for 2hr) better core loss due to grin growt occurred during the heat treatment. Decarburization of the steel substrate is also found unaffectrd by the presence of carbon in the insulation layer.

• Journal of the Microelectronics and Packaging Society
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• v.16 no.4
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• pp.17-22
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• 2009

Two different organic-inorganic hybrid thin film transistors (OITFTs) with the structures of glass/ITO/ZnO/PMMA/Al (staggered structure) and glass/ITO/PMMA/ZnO/Al (inverted staggered structure), were fabricated and their electrical and structural properties were compared. The ZnO thin films used as active channel layers were deposited by the atomic layer deposition (ALD) method at a temperature of $100^{\circ}C$. To investigate the effect of the substrates on their properties, the ZnO films were deposited on bare glass, PMMA/glass and ITO/glass substrates and their crystal properties and surface morphologies were analyzed. The structural properties of the ZnO films varied with the substrate conditions. The ZnO film deposited on the ITO/glass substrate showed better crystallinity and morphologies, such as a higher preferred c-axis orientation, lower FWHM value and larger particle size compared with the one deposited on the PMMA/glass substrate. The field effect mobility ($\mu$), threshold voltage ($V_T$) and $I_{on/off}$ switching ratio for the OITFT with the staggered structure were about $0.61\;cm^2/V{\cdot}s$, 5.5 V and $10^2$, whereas those of the OITFT with the inverted staggered structure were found to be $0.31\;cm^2/V{\cdot}s$, 6.8 V and 10, respectively. The improved electrical properties for the staggered OITFTs may originate from the improved crystal properties and larger particle size of the ZnO active layer.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.543-544
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• 2006

Pentacene thin film transistors fabricated without photolithographic patterning were fabricated on the plastic substrates. Both the organic/inorganic thin films and metallic electrode were patterned by shifting the position of the shadow mask which accompanies the substrate throughout the deposition process. By using an optically transparent zirconium oxide ($ZrO_2$) as a gate insulator and octadecyltrimethoxysilane (OTMS) as an organic molecule for self-assembled monolayer (SAM) to increase the adhesion between the plastic substrate and gate insulator and the mobility with surface treatment, high-performance transistor with field effect mobility $.66\;cm^2$/V s and $I_{on}/I_{off}$>$10^5$ was formed on the plastic substrate. This technique will be applicable to all structure deposited at low temperature and suitable for an easy process for flexible display.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1185-1188
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• 2006

Pentacene thin film transistors (OTFTs) on flexible polyimide substrate using electroplated gate electrode and organic/high-k inorganic bilayer gate dielectric layer. Incorporation of thin atomic-layer deposited $HfO_2$ layer on the PVP organic gate dielectric layer reduced the gate leakage and as a result enhanced the current on/off ratio.

• Polymer(Korea)
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• v.24 no.3
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• pp.389-398
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• 2000

Transparent, abrasion resistant coatings with 4~13 ${\mu}{\textrm}{m}$ thickness were prepared by spin-coating on polycarbonates with organic/inorganic hybrid solutions, followed by UV curing and heat treatment at 12$0^{\circ}C$ for 12 hours. The coating solutions were composed of inorganic phase and organic phase in 0:100, 20:80, 30:70, 50:50, 80:20 wt% ratios, respectively, mixed with photoinitiator, senaitizer and surfactant. The inorganic phase was formed by sol-gel reaction of TEOS and silane coupling agent MPTMS in 1 : 2 or 2 : 1 molar ratios, the organic phase consisted of difunctional urethane acrylate oligomeric resin, multifunctional acrylate TMPTA and HDDA in 4 : 3 : 3 wt% ratio. The coating systems were investigated by FT-IR, $^{29}$ Si-NMR spectra. In addition, TGA/DSC for thermal analysis and SEM, AFM observation for coated surface were examined. Gererally, the homogeneity of phases, the surface smoothness of coating and abrasion resistance were improved with the higher content of inorganic component. Namely, coating system with below 10 $\AA$ surface roughness and T$_{g}$ of 15$0^{\circ}C$ showed only 10% decrease in light transmittance after abrasion test, whereas uncoated polycarbonate substrate exhibited 46% decrease..

• Corrosion Science and Technology
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• v.14 no.2
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• pp.64-75
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• 2015

Single $TiO_2$ coating prepared by sol-gel process usually experiences cracks in coating layer. In order to prevent cracks, an inorganic-organic hybrid $TiO_2-SiO_2$ coating was synthesized by combining precursors with an organic functional group. Five different coatings with various ratios of (1:8, 1:4, 1:1, 1:0.25 and 1:0.125) titanium alkoxide (TBOT, Tetrabutylorthotitanate) to organo-alkoxysilane (MAPTS, ${\gamma}$-Methacryloxy propyltrimethoxysilane) on carbon steel substrate were made by sol-gel dip coating. The prepared coatings were analyzed to study the coating properties (surface crack, thickness, composition) by scanning electron microscope (SEM), focused ion beam (FIB), and Fourier transform infrared spectroscopy (FT-IR). Potentiodynamic polarization tests and electrochemical impedance spectroscopy (EIS) were also performed to evaluate the corrosion characteristics of the coatings. Crack free $TiO_2-SiO_2$ hybrid coatings were prepared with the optimization of the ratio of TBOT to MAPTS. The corrosion rates were significantly decreased in the coatings for the optimized precursor ratio without cracks.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.190-193
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• 2002

The processing technology of organic thin-film transistors (Ons) performances have improved fur the last decade. Gate insulator layer has generally used inorganic layer, such as silicon oxide which has properties of a low electrical conductivity and a high breakdown field. However, inorganic insulating layers, which are formed at high temperature, may affect other layers termed on a substrate through preceding processes. On the other hand, organic insulating layers, which are formed at low temperature, dose not affect pre-process. Known wet-processing methods for fabricating organic insulating layers include a spin coating, dipping and Langmuir-Blodgett film processes. In this paper, we propose the new dry-processing method of organic gate dielectric film in field-effect transistors. Vapor deposition polymerization (VDP) that is mainly used to the conducting polymers is introduced to form the gate dielectric. This method is appropriate to mass production in various end-user applications, for example, flat panel displays, because it has the advantages of shadow mask patterning and in-situ dry process with flexible low-cost large area displays. Also we fabricated four by four active pixels with all-organic thin-film transistors and phosphorescent organic light emitting devices.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.973-976
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• 2006

In this paper, the inorganic multi-layer encapsulation of thin film was newly adopted to protect the organic layer from moisture and oxygen. Using the electron beam, Sputter, inorganic multi-layer thin-film encapsulation was deposited onto the Ethylene Terephthalate(PET) and their interface properties between inorganic and organic layer were investigated. In this investigation, the SiON $SiO_2$ and parylene layer showed the most suitable properties. Under these conditions, the water vapor transmission rate (WVTR) for PET can be reduced from level of $0.57g/m^2/day$ (bare substrate) to $1^{\ast}10^{-5}g/m^2/day$ after application of a SiON and $SiO_2$ layer. These results indicate that the $PET/SiO_2/SiON/Parylene$ barrier coatings have high potential for flexible organic light-emitting diode(OLED) applications.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.3
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• pp.135-140
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• 2016

In this study, we developed the solution-processed PMMA-$HfO_x$ hybrid ReRAM devices to overcome the respective drawbacks of organic and inorganic materials. The performances of PMMA-$HfO_x$ hybrid ReRAM were compared to those of PMMA- and $HfO_x$-based ReRAMs. Bipolar resistive switching behavior was observed from these ReRAMs. The PMMA-$HfO_x$ hybrid ReRAMs showed a larger operation voltage margin and memory window than PMMA-based and $HfO_x$-based ReRAMs. The reliability and electrical instability of ReRAMs were remarkably improved by blending the $HfO_x$ into PMMA. An Ohmic conduction path was commonly generated in the LRS (low resistance state). In HRS (high resistance state), the PMMA-based ReRAM showed SCLC (space charge limited conduction). the PMMA-$HfO_x$ hybrid ReRAM and $HfO_x$-based ReRAM revealed the Pool-Frenkel conduction. As a result of flexibility test, serious defects were generated in $HfO_x$ film deposited on PI (polyimide) substrate. On the other hand, the PMMA and PMMA-$HfO_x$ films showed an excellent flexibility without defect generation.