• Journal of Sensor Science and Technology
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• v.22 no.5
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• pp.327-332
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• 2013

Nickel oxide films using RF sputter was formed on the $SiO_2/Si$ substrate at the room temperature controlled with water circulation system. The feasibility of nickel oxide film as a bolometric material was demonstrated. GIXRD spectrum on NiO(111), NiO(200), and NiO(220) orientation expected as the main peaks were appeared in the grown nickel oxide films. The typical resistivity acquired at the RF power of 100W was about $34.25{\Omega}{\cdot}cm$. And it was reduced to $18.65{\Omega}{\cdot}cm$ according to the increase of the RF power to 400W. The TCR of fabricated micro-bolometer with the resistivity of $34.25{\Omega}{\cdot}cm$ was $-2.01%/^{\circ}C$. The characteristics of fabricated nickel oxide film and micro-bolometer were analyzed with XRD pattern, resistivity, TCR, and SEM images.

• Journal of Sensor Science and Technology
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• v.19 no.3
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• pp.202-208
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• 2010

This study examined the dependency of crystalline orientation and electric properties of sol-gel PZT film on hydrolysis, a $PbTiO_3$ seed layer and a concentration of sol-gel solution. The PZT thin films were prepared by using 2-Methoxyethanol-based sol-gel method and spin-coating on Pt/Ti/$SiO_2$/Si substrates. The 1-${\mu}m$-thick PZT films were coated and then fired in a furnace by direct insert method. The highly (111) oriented PZT film of pure perovskite structure could be obtained. We could control the degree of orientation by various parameters such as hydrolysis, a $PbTiO_3$ seed layer and a concentration of sol-gel solution. The highest measured remanent polarization, dielectric constant and piezoelectric coefficient are $24.16\;{\mu}C/cm^2$, 2808, and 159 pC/N, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.51-54
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• 2003

Tb-doped lead zirconate titanate($Pb_{1.1}(Zr_{0.6}Ti_{0.4})O_3$; PZT) thin films on $Pt(111)/Ti/SiO_2/Si(100)$ substrates prepared by a sol-gel method. Films have a Zr/Ti ratio of 60:40 and perovskite phase structure. The effect on the structural and electrical properties of films measured according to Tb content. Dielectric and ferroelectric properties of PZT thin films were altered significantly by Tb-doping. The PZT thin film with higher dielectric constant and improved leakage current characteristic was obtained by adding 0.3 mol% Tb. At 100 kHz, the dielectric constant and the dielectric loss of the 0.3 mol% Tb-doped PZT thin film were 1611 and 0.24, respectively The remanent polarization(2Pr) of the 0.3 mol% Tb-doped PZT thin film was $61.4\;{\mu}C/cm^2$ and the coercive field was 61.9 kV/cm. Tb-doped PZT thin films showed improved fatigue characteristics comparing to the undoped PZT thin film.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.341-342
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• 2006

Gadolinium-substituted bismuth titanate, $Bi_{3.3}Gd_{0.7}Ti_3O_{12}$ (BGT), thin films were successfully fabricated on Pt(111)/Ti/$SiO_2$/Si substrates by a sol-gel method and their structural and ferroelectric properties have been characterized. Fabricated BGT thin films were found to be random orientations, which were confirmed by X-ray diffraction experiment and scanning electron microscope analysis. The remanent polarization ($2P_r$)) of BGT thin film annealed at $720^{\circ}C$ was $25.85\;{\mu}C/cm^2$ at an applied voltage of 5 V. The BGT thin films exhibited a 11 % reduction in their switching charge after no less than $10^{11}$ switching cycles at a frequency of 1 MHz.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.12-13
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• 2006

Ferroelectric Cerium-substituted $Bi_4Ti_3O_{12}$ thin films with a thickness of 200 nm were deposited using the liquid delivery metal organic chemical vapor deposition process onto a Pt(111)/Ti/$SiO_2$/Si(100) substrate. At annealing temperature above $600^{\circ}C$, the BCT thin films became crystallized and exhibited a polycrystalline structure. The BCT thin film annealed at $720^{\circ}C$ showed a large remanent polarization ($2P_r$) of $44.56\;{\mu}C/cm^2$ at an applied voltage of 5V. The BCT thin film exhibits a good fatigue resistance up to $1{\times}10^{11}$ switching cycles at a frequency of 1 MHz with applied electric field of ${\pm}5\;V$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.108-109
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• 2006

ZnO semiconductor has a wide band gap of 3.37 eV and a large exciton binding energy of 60 meV, and displays excellent sensing and optical properties. In particular, ZnO based 1D nanowires and nanorods have received intensive attention because of their potential applications in various fields. We grew ZnO buffer layers prior to the growth of ZnO nanorods for the fabrication of the vertically well-aligned ZnO nanorods without any catalysts. The ZnO nanorods were grown on Si (111) substrates by vertical MOCVD. The ZnO buffer layers were grown with various thicknesses at $400^{\circ}C$ and their effect on the formation of ZnO nanorods at $300^{\circ}C$ was evaluated by FESEM, XRD, and PL. The synthesized ZnO nanorods on the ZnO film show a high quality, a large-scale uniformity, and a vertical alignment along the [0001]ZnO compared to those on the Si substrates showing the randomly inclined ZnO nanorods. For sample using ZnO buffer layer, 1D ZnO nanorods with diameters of 150-200 nm were successively fabricated at very low growth temperature, while for sample without ZnO buffer the ZnO films with rough surface were grown.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.171-171
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• 2007

Dysprosium-doped bismuth titanate (BDT) thin films were successfully deposited on Pt(111)/Ti/$SiO_2$/Si(100) substrates by liquid delivery MOCVD process and their structural and ferroelectric properties were characterized. Fabricated BDT thin films were found to be random orientations, which were confirmed by X-ray diffraction experiment and scanning electron microscope analysis. The crystallinity of the BDT films was improved and the average grain size increased as the crystallization temperature increased from 600 to $720^{\circ}C$ at an interval of $40^{\circ}C$. The BDT thin film annealed at $720^{\circ}C$ showed a large remanent polarization (2Pr) of $52.27\;{\mu}C/cm^2$ at an applied voltage of 5V. The BDT thin film exhibits a good fatigue resistance up to $1.0{\times}10^{11}$ switching cycles at a frequency of 1 MHz with applied pulse of ${\pm}5\;V$. These results indicate that the randomly oriented BDT thin film is a promising candidate among ferroelectric materials useti비 in lead-free nonvolatile ferroelectric random access memory applications.

• Polymer(Korea)
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• v.31 no.2
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• pp.111-116
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• 2007

Polyurethane modified acrylate $(PUA)/SiO_2$ hybrid films were prepared by ultraviolet curing and their surface properties were investigated by hardness and adhesion test. The films were examined by the manipulation of mole-ratio of organic to inorganic components. Under the silica content controlled, highly desirable films were achieved and scratch resistance and hardness property of film were also enhanced, which indicates that the crosslinked silica particles are homogeneously dispersed within PUA film.

• Korean Journal of Materials Research
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• v.9 no.6
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• pp.583-588
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• 1999

The characteristics of copper thin films and pattern filling capability were investigated by ECD. Prior to deposition of copper film, seed-Cu/Ta(TaN)/$SIO_2$(BPSG)/Si structure was manufactured. Copper deposition was performed with various current waveforms(DC/PC, 1~10,000Hz) and current densities(10~60 mA/$\textrm{cm}^2$) after pretreatment (Oxident removal, wetting) of seed-layer. Conformal pattern filling was performed using PC method with fast deposition rate of 6,000~8,000$\AA$/min. Heat-treated($450^{\circ}C$, 30min) copper films showed good resistivities of 1.8~2.1$\mu$$\Omega$.cm. According to the XRD analysis, (111)-preferred orientation of copper film was found in ECD-Cu/seed-Cu/Ta/$Sio_2$/Si structure. Also, we have successfully achieved to fill via holes with 0.35$\mu\textrm{m}$ width and 4:1 aspect ratio.

• Preventive Nutrition and Food Science
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• v.3 no.2
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• pp.111-118
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• 1998

To develop a simple, rapid and simultaneous analytical method of phenolic compounds using gas chromatography (GC) and gas chromatography/mass spectrophometer (GC/Ms), this experiment was carried out to search the retention times of capillary columns and the characteristics of fragment ions in electron impact mass spectra. Most of trimethylsilyl derivatives and underivatized phenolic compounds were separated very well on three kinds of capillary columns(HP-1), Ultra-2 and HP-35). Quantitiative determination of phenolic compounds was achieved by internal standards (p-hydroxybenzoic acid iopropyl ester, p-hydroxybenzoic acid ethyl ester). Calibration plts were linear in the investigated range, and the limits of detection were about 5 ng at split mode method. When analyzed by three columns, theseparation times were fairly constant on two nonpolar columns, but a few compounds showed slightly different separation order by the itnermediate polar HP-35 column. The important characteristic patterns of TMS derivatives of phenolic compounds on the EI/MS spectrra appeared at the base peak of [M-15]+ ion and presented at high abundance in most TMS derivatives of phenoloc compounds. [M]+, [M-CH3-COO]+, [M-Si(CH3)4]+ and [M-Si(CH3)4 -CH3]+ also observed in mass spectra of these compounds . Although several compounds have the same retention times on GC column, it might be possible to identify these compounds by the different patternsof mass frgement ions. The TMS derivatives, thus , provide additional information for identification of phenolic compounds in biological systems.