• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.11
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• pp.895-899
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• 2011

Multiferroic BFO/PZT(5/95) multilayer films were fabricated by spin-coating method on the Pt/Ti/$SiO_2$/Si substrate alternately using BFO and PZT(9/95) alkoxide solutions. The structural and dielectric properties were investigated with variation of the solvent and the number of coatings. All films showed the typical XRD patterns of the perovskite polycrystalline structure without presence of the second phase such as $Bi_2Fe_4O_3$. BFO/PZT multilayer thin films showed the typical dielectric relaxation properties with increase an applied frequency. The average thickness of 6-coated BFO/PZT multilayer film was about 600 nm. The dielectric properties such as dielectric constant, dielectric loss and remnant polarization were superior to those of single composition BFO film, and those values for BFO/PZT multilayer film were 1199, 0.23% and 12 ${\mu}C/cm^2$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.2
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• pp.138-145
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• 1998

The $(Pb_{0.9}Ca_{0.1})TiO_3$[PCT] thin films have been deposited by sol-gel processing on Si-wafer and ITO glass substrates. The creak-free films have been obtained by rapid thermal annealing at $700^{\circ}C$ for 10 minute and characterized by XRD, SEM and electrical measurements. Their tetragonality c/a was 1.041 and grain size was $0.15{\sim}0.2{\mu}m$. When the electrode system of sample was Au/PCT/ITO(MFM) and film thickness was $0.8{\mu}m$, dielectric constant, dielectric loss and Curie temperature were about 149, 0.085 and $449^{\circ}C$ at 10kHz, respectively. Spontaneous polarization $P_s$, remnant polarization $P_r$ and coercive field $E_c$ were about $5.29{\mu}C/cm^2$, $4.15{\mu}C/cm^2$ and 82kV/cm calculated by hysteresis loop.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1505-1507
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• 1996

In this study, $(Pb_{0.88}La_{0.12})(Zr_{0.40}Ti_{0.60})O_{2.97}$ (La/Zr/Ti=12/40/60) ceramic thin films were fabricated from an alkoxide-based by Sol-Gel method. PLZT stock solutions were made and spin-coated on the ITO-glass rubstrate at 4000[rpm] for 30[sec]. Coated specimens were baked to remove the organic materials at $400[^{\circ}C]$ for 10[min]. This procedure was repeated 5 times. The coated films were finally annealed at $450{\sim}700[^{\circ}C]$ for 1[hr]. The ferroelectric perovskite phases precipitated under the sintering of $550{\sim}700[^{\circ}C]$ for 1[hr]. Relative dielectric constant of the PLZT thin were increased with increasing the sintering temperature, the thin file sintered at $650[^{\circ}C]$ showed the highest value of 196. But in the PLZT thin film sintered at $700[^{\circ}C]$, relative dielectric constant was greatly decreased due to reacts between ITO electrode and glass substrate. In all thin films, the transmittance was more than 70[%] (at 632.8[nm]).

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.335-337
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• 1995

In this study, $Pb(Zr_{0.52}Ti_{0.48})O_3$ ceramic thin films were fabricated from an alkoxide-based by Sol-Gel method. $Pb(Zr_{0.52}Ti_{0.48})O_3$ stock solution was made and spin-coated on the $Pt/SiO_2/Si$ substrate at 4000[rpm] for 30[sec]. Coated specimens were dried at 400[$^{\circ}C$] for 10 [min]. The coating process was repeated 4 times and then heat-treated at 500$\sim$800[$^{\circ}C$], 1 hour. The final thickness of the thin films were about 3000[A]. The crystallinity and microstructure of the thin films were investigated for varing the sintering condition. The ferroelectric perovskite' phases precipitated under the sintering of 700[$^{\circ}C$] for 1 hours. In the $Pb(Zr_{0.52}Ti_{0.48})O_3$ thin films sintered at 700[$^{\circ}C$] for 1 hour, dielectric constant and dielectric loss were 2133, 2.2[%] at room temperature, respectively. $Pb(Zr_{0.52}Ti_{0.48})O_3$ thin film capacitors having good dielectric and electrical properties are expected for the application to the dielectric material of DRAM.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.364.2-364.2
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• 2014

Magnesium oxide (MgO) thin films have attracted great scientific and technological interest in recent decades. Because of its distinguished properties such as a wide band gap (7.2 eV), a low dielectric constant (9.8), a low refractive index, an excellent chemical, and thermal stability (melting point=$2900^{\circ}C$), it is widely used as inorganic material in diverse areas such as fire resistant construction materials, optical materials, protective layers in plasma display panels, buffer layers of multilayer electronic/photonic devices, and perovskite ferroelectric thin films. Precursor used in the ALD requires volatility, stability, and low deposition temperature. Precursors using a heteroleptic ligands with different reactivity have advantage of selective reaction of the heteroleptic ligands on substrate during ALD process. In this study, we have synethesized new heteroleptic magnesium precursors ${\beta}$-diketonate and aminoalkoxide which have been widely used for the development of precursor because of the excellent volatility, chelating effects by increasing the coordination number of the metal, and advantages to synthesize a single precursor. A newly-synthesized Mg(II) precursor was adopted for growing MgO thin films using ALD.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.1
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• pp.1-5
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• 2001

P(VDF/TrFE) copolymer thin films with 70/30 and 80/20 mol% VDF (polyvinylidene fluoride) and TrFE (trifluoroethylene) rates were prepared by using a vapor deposition method, During thin films were prepared, the substrate temperatures were maintained at 30 $^{\circ}C$ and 120 $^{\circ}C$, and the heating source temperature was fixed at 350 $^{\circ}C$. Contary to PVDF homopolymer, P(VDF/TrFE) copolymers showed the Curie point(Tc) below the melting point. The Curie point (Tc) and the melting point of the P(VDF/TrFE) copolymers were changed as a function of substrate temperature and the VDF mol%. The Curie point and the melting point of P(VDF/TreFE) thin films decreased and increased with increasing substrate temperature, respectively. Also with increasing VDF mol%, the melting point decreased slightly, however the Curie point increased.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.8
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• pp.694-699
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• 2000

S $r_{0.9}$/B $i_{2.1}$/T $a_{2}$/ $O_{9}$ solutions was synthesized by MOD (metalorganic decomposition) method. SBT thin films with 2000$\AA$ thickness were prepared on Ir $O_2$/ $SiO_2$/Si and Pt/Ti/ $SiO_2$/Si substrates using the spin coating process and then investigated the dielectric and electrical properties of them. In the case of using Ir $O_2$bottom electrode the hysteresis loop was saturated at lower temperature than Pt/Ti electrode but the breakdown phenomenon was occurred at low voltage because of the rough surface morphology and porous microstructure of SBT thin films. As the results of the fatigue and imprint characteristics related to the lifetime and reliability of devices after 10$^{10}$ cycles the fatigue rates were about 10% at the Ir $O_2$and Pt/Ti bottom electrodes. Both SBT thin films with Ir $O_2$ and with Pt/Ti bottom electrodes show a slight tendency to imprint after 10$^{9}$ cycles but do not lead to a failure.e.e.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1454-1456
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• 1994

$Pb(Zr_{0.52}Ti_{0.48})O_3$ ceramic thin films were fabricated from an alkoxide-based solution by Sol-Gel method. $Pb(Zr_{0.52}Ti_{0.48})O_3$ ceramic thin films were formed by spin coating method on $Pt/SiO_2/Si$ substrate at 3000rpm for 30 seconds. The coating process was repeated 6 times and then heat-treated at temperature between 500 - $800[^{\circ}C]$ for 1 hour. The final thickness of the thin films were about 4800[A]. The 100% ferroelectric perovskite phases precipitated under the heat treated at $700[^{\circ}C]$ for 1 hour. $Pb(Zr_{0.52}Ti_{0.48})O_3$ thin films heat-treated at $700[^{\circ}C]$ for 1 hour showed good dielectric constant (812) property.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.9
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• pp.731-735
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• 2001

S $r_{0.89}$B $i_{2.4}$T $a_2$ $O_{9}$ (SBT) thin films are deposited on Pt-coated electrode(Pt/Ti $O_2$/ $SiO_2$/Si) using RF magnetron sputtering method. In the XRD pattern, the SBT thin films had (105) orientation. As annealing temperature was increased from $600^{\circ}C$ to 85$0^{\circ}C$, the intensities of peak were increased. In the SEM images, Bi-layered perovskite phase was crystallized above $650^{\circ}C$ and rod-like grains grew above 75$0^{\circ}C$. The maximum remanent polarization and the coercive electric field at annealing temperature of 75$0^{\circ}C$ are 11.60$\mu$C/$\textrm{cm}^2$ and 48kV/cm respectively. The dielectric constant and leakage current density at annealing temperature of 75$0^{\circ}C$ are 213 and 1.01x10$^{-8}$ A/$\textrm{cm}^2$, respectively. The fatigue characteristics of SBT thin filmsdid not change up to 10$^{10}$ switching cycles.s.s.

• Bulletin of the Korean Chemical Society
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• v.30 no.1
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• pp.201-204
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• 2009

$BaTiO_3/SrTiO_3$ and $PbTiO_3/PbZrO_3$ superlattice thin films were fabricated on $Pt/Ti/SiO_2/Si$ substrate by the pulsed laser deposition process. The morphologies and physical properties of deposited films were characterized by using X-ray diffractometer, HR-SEM, and Impedance Analyzer. XRD data and SEM images of the films indicate that each layer was well deposited alternatively in the superlattice structure. The dielectric constant of $BaTiO_3/SrTiO_3$ superlattice thin film was higher than that of individual $BaTiO_3$ or $SrTiO_3$ film. Same result was obtained in the $PbTiO_3/PbZrO_3$system. The dielectric constant of a superlattice film was getting higher as the number of layer is increased.