• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.191-191
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• 2009

$Bi_4Ti_3O_{12}$ (BiT) thin films were well developed on the Pt/Ti/$SiO_2/Si$ substrate by a metal organic decomposition (MOD) method. Oxygen was effective on the crystallization of the BiT thin films during a rapid thermal annealing process. The electrical properties of the BiT films dependant on the oxygen partial pressure were investigated. No crystalline phase was observed for the BiT film annealed at $700^{\circ}C$ under oxygen free atmosphere. However, its crystallinity was significantly evolutionned with increasing oxygen partial pressure. In addition, its dielectric and piezoelectric properties were enhanced with increasing oxygen partial pressure to 10 torr. Especially, the BiT film, annealed at $700^{\circ}C$ and 10 torr oxygen pressure, showed good dielectric properties: dielectric constant of 51 and dielectric loss of 0.2 % at 100 kHz. Its leakage current and piezoelectric constant ($d_{33}$) was also considerably improved, being as 0.62 nA/$cm^2$ at 1 V and approximately 51 pm/V, respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.4
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• pp.290-296
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• 2009

$Bi_{4}Ti_{3}O_{12}$ (BiT) thin films were grown on the Pt/Ti/$SiO_2$/si substrate using a metal organic decomposition (MOD) method. Effects of oxygen annealing on the structural properties and dielectric properties of the BiT thin films were investigated. The BiT films were well developed when rapid thermal annealed at $>500^{\circ}C$ in oxygen ambient. For the film annealed at $700^{\circ}C$, no crystalline phase was observed under oxygen free annealing atmosphere while its crystallinity was significantly enhanced as the oxygen pressure increased. The BiT film also exhibited a smooth surface with defect free grains. A high dielectric constant and a low dielectric loss were achieved satisfactory in the frequency range from 75 kHz to 1 MHz. Especially, the BiT film, annealed at $700^{\circ}C$ and 10 torr oxygen pressure, showed good dielectric properties: dielectric constant of 51 and dielectric loss of 0.2 % at 100 kHz. Its leakage current was also considerably improved, being as $0.62\;nA/cm^2$ at 1 V. Therefore, it is considered that the oxygen annealing has effects on an enhancement of crystallinity and dielectric properties of the BiT films.

• Korean Journal of Materials Research
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• v.11 no.8
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• pp.671-678
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• 2001

All solid-state thin film micro supercapacitor, which consists of $RuO_2$/LiPON/$RuO_2$ multi layer structure, was fabricated on Pt/Ti/Si substrate using a $RuO_2$ electrode. Bottom $RuO_2$ electrode was grown by dc reactive sputtering system with increasing $O_2/[Ar+O_2]$ ratio at room temperature, and a LiPON electrolyte film was subsequently deposited on the bottom $RuO_2$ electrode at pure nitrogen ambient by rf reactive sputtering system. Room temperature charge-discharge measurements based on a symmetric $RuO_2$/LiPON/$RuO_2$ structure clearly demonstrates the cyclibility dependence on the microstructure of the $RuO_2$ electrode. Using both glancing angle x-ray diffraction (GXRD) and transmission electron microscopy (TEM) analysis, it was found that the microstructure of the $RuO_2$ electrode was dependent on the oxygen flow ratio. In addition, x- ray photoelectron spectroscopy(XPS) examination shows that the Ru-O binding energy is affected by increasing oxygen flow ratio. Furthermore, TEM and AES depth profile analysis after cycling demonstrates that the interface layer formed by interfacial reaction between LiPON and $RuO_2$ act as a main factor in the degradation of the cyclibility of the thin film micro-supercapacitor.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04b
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• pp.92-95
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• 2000

The $(Sr_{1-x}Ca_x)TiO_3$(SCT) thin films are deposited on Pt-coated electrode(Pt/TiN/$SiO_2$/Si) using RF sputtering method with substitutional contents of Ca. The maximum grain of thin films is obtained at SCT15 thin film. The dielectric constant was increased with increasing the substitutional contents of Ca, while it was decreased if the substitutional contents of Ca exceeded over 15[mol%]. The dielectric constant changes almost linearly in temperature ranges of -80~+90$[^{\circ}C]$. The temperature properties of the dielectric loss have a stable value within 0.02 independent of the substitutional contents of Ca. All SCT thin films used in this study show the phenomena of dielectric relaxation with the increase of frequency, and the relaxation frequency is observed above 200[kHz].

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.10
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• pp.559-563
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• 2000

The $(Sr_{1-x}Ca_x)TiO_3(SCT)$ thin films are deposited on Pt-coated(Pt/TiN/$SiO_2$/Si) using RF sputtering method with substitutional contents of Ca. The maximum grain of thin films is obtained by substitution of Ca at 15[mol%]. Also the composition of SCT thin films were closed to stoichiometry(1.081∼1.117 in A/B/ ratio). The dielectric constant was increased with increasing the substitutional contents of Ca, while it was decreased if the substitutional contents of Ca exceeded over 15[mol%]. The dielectric constant changes almost linearly in temperature ranges of -80∼+90[^${\circ}C$]. The temperature properties of the dielectric loss have a stable value within 0.02 independent of the substitutional contents of Ca. All SCT thin films used in this study show the phenomena of dielectric relaxation with the increase of frequency, and the relaxation frequency is observed above 2000[kHz]. The current-voltage characteristics of SCT15 thin films showed the increasing leakage current as the measuring temperature increase.

• Journal of the Korean Ceramic Society
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• v.22 no.6
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• pp.71-79
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• 1985

In order to fabricate the translucent electrooptic ceramics which are comparable to PLZT, $PNZT^*$ has been prepared from aqueous solutions of their itrate and chlorides. In the quarternary $Pb^{1-x} Nd_x(Zr_{0.63} Ti_{0.37})^{1-\frac{x}{4}O_3$, (PNZT) $(0.02\le x\ge 0.12)$ system cold-pressed PNZT slugs were sintered in $O_2$ in pt-crucible for 45 min. at 118$0^{\circ}C$ and were then heat-treated in air for 60 hrs. at 120$0^{\circ}C$ in Al2O3 crucibles containing $PbZrO_3$ powder to control the atmosphere. Mean particle size of calcined PNZT powders was 0.1~0.15${\mu}{\textrm}{m}$. It was found that the maximum value of optical transmission has been revealed at 6~8 at. % $Nd_2O_3$ added body and that their dielectric constant has been decreased as the frequency increased. Curic temperature has been varied inversely with $Nd^{3+}$ ion content up to 8 at. % and become constant above this value. $^*Pb_{1-x}Nd_x(Zr_{0.63} Ti_{0.37})_{1-2/4}O_3$

• Journal of the Korean Vacuum Society
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• v.13 no.4
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• pp.145-149
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• 2004

We have grown piezoelectric oxide films by RF magnetron sputtering using miscut substrates. Films were Brown on(001) $SrTiO_3$ substrates with miscut angles from 0 to 8 degrees toward the (100) direction. Films on high miscut substrates (>$4^{\circ}$) showed almost the pure perovskite phase in x-ray diffraction and were nearly stoichiometric. In contrast, films on exact (001) $SrTiO_3$ contained a high volume fraction of pyrochlore phases. A film on an $8^{\circ}$ miscut substrate exhibits a polarization hysteresis loop with a remnent polarization of 20$\mu$C/$\textrm{cm}^2$ at room temperature.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.4
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• pp.265-271
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• 2003

Ferroelectric lanthanum-substituted Bi$_4$Ti$_3$O$_{12}$(BLT) thin films were fabricated by spin-coating onto a Pt/Ti/SiO$_2$/Si substrate by metalorganic decomposition technique. The grain size in BLT thin films were prepared with controlled by various drying process. The effect of grain size on the crystallization and ferroelectric properties were investigated by x-ray diffraction and field emission scanning electron microscope. The dependence of crystallization and electrical properties are related to the grain size in BLT thin films with different drying temperature. The remanent polarization of BLT thin film increases with the increasing grain size. The value of 2P$_{r}$ and E$_{c}$ of BLT thin film dried at 45$0^{\circ}C$ were 25.9 $\mu$C/$\textrm{cm}^2$ and 85 kV/cm, respectively. The BLT thin film with larger grain size has better fatigue properties. The fatigue properties revealed that small grained film showed more degradation of switching charge than large grained films.lms.s.

• 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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• 2005.07a
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• pp.615-616
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• 2005

Carbon Nanotubes (CNT) on flexible indium tin oxide (ITO) PET films were prepared for dye-sensitized solar cell (DSSC). These CNTs were prepared by spray coating method for various amount of light transparency. Also, Pt counter electrode was prepared by electro deposition method. All $TiO_2$ electrodes were deposited on ITO-PET films by spray coating method. Micro structural images show that CNT counter electrodes prepared by spray-coating have more dense structure with increasing spraying time (0 to 60 seconds). DSSC consisting of $TiO_2$ electrode and CNT counter electrode was fabricated with various amount of light absorption. DSSC have higher light energy conversion efficiency with increasing the thickness of CNT counter electrode. CNT counter electrode is at least compatible to that of CNT counter electrode.