• Transactions of Materials Processing
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• v.13 no.1
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• pp.59-64
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• 2004

Nano-scratch tests were performed on PMMA thin films spin-coated on a Si substrate using an atomic force microscopy (AFM) with loads ranging form 10nN to 100nN. At low loads, a ridge pattern was formed on the PMMA thin film surface. No wear particles were observed during the pattern-forming mild wear. At high loads, severe wear by plowing occurred, accompanied by wear particles. The film with the highest hardness showed the highest wear resistance. Friction force generated during the scratching was measured, which was closely related with surface deformation of the film. A simple empirical equation to deduce scratch hardness of the film from a linear fixed-distance scratch test was proposed, and scratching-speed dependency of the scratch hardness was displayed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.05b
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• pp.29-32
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• 2005

Poly (methyl methacrylate) (PMMA) is one of the promising representive of polymer gate dielectric for its high resistivity and sutible dielectric constant. PMMA (Mw=96700) films were prepared on p-Si by spin coating method. PMMA were coated compactively and flatly as observeed by AFM. MIS(Al/PMMA/p-Si) structure was made and capacitance-voltage (C-V) and current-voltage (I-V) measurements were done with PMMA films for different thermal treatment temperature. PMMA films were showed proper dielectric constant and breakdown voltage. Above the glass transition temperature PMMA films degraded. C-V measured at various frequencies, dielectric constant increased a little. The absence of hysteresis in the C-V characteristics, which eliminate the possibility of mobile charges in the PMMA films. The observed thermal stability, smooth surfaces, dielectric constant, I-V behavior implies PMMA formed by spin coating can be used as an efficient gate dielectric layer in OTFTs.

• Journal of the Microelectronics and Packaging Society
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• v.12 no.2 s.35
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• pp.181-186
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• 2005

We fabricated thin films of polystyrene-block-poly(methyl methacrylate)(PS -b-PMMA) on the self-assembled monolayers(SAM) of 3-(p-methoxyphenyl)propyltrichlorosilane(MPTS) on silicon wafers. Cylindrical nanodomains of PMMA or PS were oriented perpendicular to the surface of silicon wafers due to the neutral affinity of the SAM to PS and PMMA blocks. By selective removal of the PMMA block with UV irradiation and washing, nanoporous films and nanorod assemblies were produced. The nanoporous film can be used for a nanolithographical mask.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.1081-1084
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• 2003

Structural morphology, annealing behavior and dielectric properties of polyaniline-emeraldine base (Pani-EB) and poly methyl methacrylate (PMMA) thin films prepared by spin coating technique have been studied. MIM and MISM structures were used to investigate annealing and dielectric behavior. The XRD and AFM spectrum of as grown and annealed thin films indicates the amorphous nature. The observed amorphous phase, low loss, dielectric behavior and thermal stability even at high temperatures implies the feasibility of utilizing PMMA and Pani-EB thin films as gate dielectric insulator layer in organic thin film transistors which can find application in flat panel display.

• ETRI Journal
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• v.18 no.3
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• pp.195-206
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• 1996

Molecular conformations of stereoregular poly(methyl methacrylate) (PMMA) monolayers have been investigated by scanning probe microscopes. Isotactic and syndiotactic PMMAs were found to have right and left hand helical structures, respectively. On the contrary atactic PMMA showed rather random arrangement of the chains. It has been demonstrated that the PMMA Langmuir-Blodgett (LB) films can be utilized to form nanoscale patterns down to 50 nm and to forma geodesic lens. It has also been manifested that the quantum efficiency of a polymer electroluminescent device can be significantly enhanced by inserting the PMMA LB films between the emitting layer and the cathode. All the applications utilize the unique characteristics of the LB films to form thin and uniform films in the molecular level.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.19 no.6
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• pp.305-310
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• 2009

$TiO_2$ thin films consisting of positively charged poly (diallyldimethylammonium chloride) (PDDA) and negatively charged titanium (IV) bis (ammonium lactato) dihydroxide (TALH) were successfully fabricated on a poly (methyl methacrylate) (PMMA) by layer-by-layer (LBL) self-assembly method. By the measurement of quartz crystal microbalance (QCM), it was found that as the solution pH of TALH decreased, the deposition volume of TALH increased and the thickness of (PDDA/TALH) thin film coated on the surface of PMMA particles increased. The PMMA particles coated with the coating sequence of (PDDA/TALH)n showed the variation of color changes as a function of the number of bilayer. The number of bilayer (n) of (PDDA/TALH) thin films was 10 and 20, the values of $a^*$ and $b^*$ decreased from those of PMMA particles without coating films and the color changes was shifted to green and blue direction in the $a^*$, $b^*$ chromaticity diagram. And then, the number of n increased to 30 and 40, the values of $a^*$ and $b^*$ increased and the color changes was shifted to red and yellow direction, respectively. Finally the PMMA particles coated with $(PDDA/TALH)_{50}$ thin film showed a little same value of $a^*$ and $b^*$ with the PMMA particles without (PDDA/TALH) thin film.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.5
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• pp.697-702
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• 2011

In this paper, We have fabricated PMMA thin films by plasma polymerization method for organic thin film transistor's insulator layer. In the electrical characteristic results with deposition pressures and substrate RF bias power in thin film deposition process, we have got dielectric constant of 3.4, high deposition rate of 8.6 [nm/min] and high insulation characteristics in condition of RF100 [W], Ar20 [sccm], 5 [mtorr], RF bias 20 [W]. Therefore, the fabricated thin films are possible as insulation layer of OTFT and organic memory.

• Journal of Electrical Engineering and Technology
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• v.4 no.1
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• pp.118-122
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• 2009

Organic thin film transistors with a pentacene active layer and various polymer gate insulators were fabricated and their performances were investigated. Characteristics of pentacene thin film transistors on different polymer substrates were investigated using an atomic force microscope (AFM) and x-ray diffraction (XRD). The pentacene thin films were deposited by thermal evaporation on the gate insulators of various polymers. Hexamethyldisilazane (HMDS), polyvinyl acetate (PVA) and polymethyl methacrylate (PMMA) were fabricated as the gate insulator where a pentacene layer was deposited at 40, 55, 70, 85, 100 oC. Pentacene thin films on PMMA showed the largest grain size and least trap concentration. In addition, pentacene TFTs of top-contact geometry are compared with PMMA and $SiO_2$ as gate insulators, respectively. We also fabricated pentacene TFT with Poly (3, 4-ethylenedioxythiophene)-Polysturene Sulfonate (PEDOT:PSS) electrode by inkjet printing method. The physical and electrical characteristics of each gate insulator were tested and analyzed by AFM and I-V measurement. It was found that the performance of TFT was mainly determined by morphology of pentacene rather than the physical or chemical structure of the polymer gate insulator

• Journal of Ceramic Processing Research
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• v.19 no.6
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• pp.525-529
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• 2018

The antireflective (AR) coated poly methyl methacrylate (PMMA) substrate was deposited by atomic layer deposition (ALD) on a self-assembled monolayer (SAM) to improve hydrophobicity and mechano-chemical properties of organic thin films. The water contact angles (WCA) were tested to characterize the surface wettability of SAM octadecyltrichlorosilane (OTS) films. Results showed that a contact angle of $105.9^{\circ}$ was obtained for the SAM films with an annealing process, and the highest WCA of $120^{\circ}$ was achieved for the films prepared by the SAM and ALD multi-process. The surface morphology of the SAM films with different assembly times and varying number of ALD cycles was obtained by atomic force microscopy (AFM). The maximum light transmittance for the SAM films on the PMMA substrate reached 99.9% at a wavelength of 450 nm. It was found that the SAM surfaces were not affected at all by the ALD process.

• Polymer(Korea)
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• v.36 no.4
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• pp.507-512
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• 2012

Thin (~650 nm) and ultrathin (~50 nm) films of neat PMMA and PMMA containing 5 wt% of methacryl-polyhedral oligomeric silsesquioxane were prepared in this work. The effects of film thickness and POSS on glass transition temperature ($T_g$) and isothermal physical aging were investigated by means of differential scanning calorimetry (DSC). $T_g$ depression was observed as film thickness was decreased and Ma-POSS molecules were incorporated. Enthalpy relaxation (${\Delta}H_{Relax}$) due to the isothermal physical aging was reduced by ultra-thin film thickness and the addition of Ma-POSS. KWW (Kohlrausch-Williams-Watts) equation was used to fit ${\Delta}H_{Relax}$ vs. aging time data providing the fitting parameters; maximum enthalpy recovery (${\Delta}H_{\infty}$), relaxation time (${\tau}$) and non-exponentiality parameter (${\beta}$).