• Journal of Sensor Science and Technology
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• v.19 no.5
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• pp.337-341
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• 2010

In this work, the nanocrystalline ZnO/polycrystalline(poly) aluminum nitride(AlN)/ Si-layered structure was fabricated for humidity sensor applications based on surface acoustic wave(SAW). The ZnO film was used as a sensitive material layer. The ZnO and AlN(0002) were deposited by a sol-gel process and a pulse reactive magnetron sputtering, respectively. The ZnO sensitive films coated on AlN have a hexagonal wurtzite structure after the thin films annealed at $400^{\circ}C$, $500^{\circ}C$ and $600^{\circ}C$. The surface of the film exhibits sponginess and a nanometer particle size(below 50 nm). The largest shift in the frequency response was at approximately 200 kHz(the relative humidity: 10 %~90 %) for the structure annealed at $400^{\circ}C$. The effect of the change in the environmental temperature on the frequency response of the SAW humidity sensor was also investigated.

• Korean Journal of Materials Research
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• v.18 no.12
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• pp.664-668
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• 2008

Vapor phase polymerization of a conductive polymer on a $SiO_2$ surface can offer an easy and convenient means to depositing pure and conductive polymer thin films. However, the vapor phase deposition is generally associated with very poor adhesion as well as difficulty when patterning the polymer thin film onto an oxide dielectric substrate. For a significant improvement of the patternability and adhesion of Poly(3-hexylthiophene) (P3HT) thin film to a $SiO_2$ surface, the substrate was pre-patterned with n-octadecyltrichlorosilane (OTS) molecules using a ${\mu}$-contact printing method. The negative patterns were then backfilled with each of three amino-functionalized silane self-assembled monolayers (SAMs) of (3-aminopropyl) trimethoxysilane (APS), N-(2-aminoethyl)-aminopropyltrimethoxysilane (EDA), and (3- trimethoxysilylpropyl)diethylenetriamine (DET). The quality and electrical properties of the patterned P3HT thin films were investigated with optical and atomic force microscopy and a four-point probe. The results exhibited excellent selective deposition and significantly improved adhesion of P3HT films to a $SiO_2$ surface. In addition, the conductivity of polymeric thin films was relatively high (${\sim}13.51\;S/cm$).

• Journal of Convergence for Information Technology
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• v.9 no.3
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• pp.75-81
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• 2019

In this work, we investigated a low temperature polycrystalline silicon (LTPS) thin film transistors fabrication process on polymer layers. Dehydrogenation and activation processes were performed by a furnace annealing at a temperature of $430^{\circ}C$ for 2 hr. The crystallization of amorphous silicon films was formed by excimer laser annealing (ELA) method. The p-type device performance, fabricated by polycrystalline silicon (poly-Si) films, shows a very good performance with field effect mobility of $77cm^2/V{\cdot}s$ and on/off ratio current ratio > $10^7$. We believe that the poly-Si formed by a LTPS process may be well suited for fabrication of poly-Si TFTs for bendable panel displays such as AMOLED that require circuit integration.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.332-333
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• 2008

DC magnetron sputtering was used to deposit p-type polycrystalline silicon on n-type Si(100) wafer. The influence of film microstructure properties on deposition parameters (DC power, substrate temperature, pressure) was investigated. The substrate temperature and pressure have the important influence on depositing the poly-Si thin films. Smooth ploy-Si films were obtained in (331) orientation and the average grain sizes are ranged in 25-30nm. The grain sizes of films deposited at low pressure of 10mTorr are a little larger than those deposited at high pressure of 15mTorr.

• Proceedings of the Materials Research Society of Korea Conference
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• 1996.11a
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• pp.114-114
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• 1996

• Journal of Sensor Science and Technology
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• v.18 no.5
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• pp.349-352
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• 2009

This paper describes the fabrication and characteristics of micro heaters built on AlN($0.1{\mu}m$)/3C-SiC($1{\mu}m$) suspended membranes by surface micromachining technology. In this work, 3C-SiC and AlN films are used for high temperature environments. Pt thin film was used as micro heaters and temperature sensor materials. The resistance of temperature sensor and the power consumption of micro heaters were measured and calculated. The heater is designed for operating temperature up to about $800^{\circ}C$ and can be operated at about $500^{\circ}C$ with a power of 312 mW. The thermal coefficient of the resistance(TCR) of fabricated Pt resistance of temperature detector(RTD)'s is 3174.64 ppm/$^{\circ}C$. A thermal distribution measured by IR thermovision is uniform on the membrane surface.

• Journal of Adhesion and Interface
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• v.9 no.4
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• pp.30-33
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• 2008

Two polymeric interfaces with single component homo-polymers were prepared to control the orientation of block copolymer thin-film nanostructures. Poly(4-acetoxy styrene) (OH-PAS) and poly(4-methoxy styrene) (OH-PMS) which have the average chemical composition of polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) were precisely synthesized through nitroxide-mediated radical polymerization. After dehydration reactions between above polymers and SiOx layers of silicon wafers, the polymer-modified interface induced partial (30%) vertical orientation of PS-b-PMMA thin film in the case of OH-PMS and wholly parallel orientation in the case of OH-PAS. Chemical compositions of polymeric interface layers are regarded as the key parameter to control the orientation of nanostructures of block copolymer thin film.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.261-264
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• 2007

We developed a non self-aligned poly-silicon TFTs fabrication process at two different temperatures on spin-coated polyimide layer above Si-wafer. After TFTs fabrication, the polyimide layer was mechanically released from the Si-wafer and the devices characteristics were compared. In addition self-heating and hot-carrier induced instabilities were analysed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.04b
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• pp.45-48
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• 2002

Poly(3-hexylthiophene) or P3HT based organic thin film transistor (OTFT) array was fabricated on flexible poly carbonate substrates and the electrical characteristics were investigated. As the gate dielectric, a dual layer structure of polyimide-$SiO_2$ was used to improve the roughness of $SiO_2$ surface and further enhancing the device performance and also source-drain electrodes were $O_2$ plasma treated for improvement of the electrical properties, such as drain current and field effect mobility. For the active layer, polymer semiconductor, P3HT layer was printed by contact-printing and spin-coating method. The electrical properties of OTFT devices printed by both methods were evaluated for the comparison. Based on the experiments, P3HT-based OTFT array with field effect mobility of 0.02~0.025 $cm^{2}/V{\cdot}s$ and current modulation (or $I_{on}/I_{off}$ ratio) of $10^{3}\sim10^{4}$ was fabricated.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.362-363
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• 2005

The objectives of this paper are to achieve good planarization of the deposited film and to improve deposition efficiency of multi-layer structures by using surface-micromaching process in MEMS technology. Planarization characteristic of poly-Si film deposited on thin oxide layer with MEMS structures is evaluated with different slurries. Patterns used for this research have shapes of square, density, line, hole, pillar, and micro engine part. Advantages and disadvantages of CMP for MEMS structures are observed respectively by using the test patterns with structures larger than 1 um line width. Preliminary tests for material selectivity of poly-Si and oxide are conducted with two types of slurries: ILD1300 and Nalco2371. And then, the experiments were conducted based on the pretest.