• Journal of Electrical Engineering and Technology
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• v.4 no.4
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• pp.527-530
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• 2009

$(Ba_{0.57}Sr_{0.33}Ca_{0.10})TiO_3$(=BSCT) powders, prepared by the sol-gel method, were doped using $MnCO_3$ as the acceptor and $Dy_2O_3$ as the donor. This powder was mixed with an organic vehicle. BSCT thick films were fabricated by the screen-printing techniques on the alumina substrate. The structural and dielectric properties of BSCT thick films were investigated with variation of the $Dy_2O_3$ amount. As a result of the differential thermal analysis (DTA), the exothermic peak was observed at around $670^{\circ}C$ due to the formation of the polycrystalline perovskite phase. All the BSCT thick films showed the XRD patterns of a typical polycrystalline perovskite structure. The average grain size of BSCT thick films decreased with an increasing amount of $Dy_2O_3$. The relative dielectric constant and dielectric loss of the BSCT thick film doped $Dy_2O_3$ 0.1mol% were 4637.4 and 1.6% at 1kHz, respectively.

• 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.

• Journal of the Korean Vacuum Society
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• v.17 no.5
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• pp.442-447
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• 2008

Ferroelectric samples of the 0.65Pb$(Mg_{1/3}Ta_{2/3})O_3-0.35PbTiO_3$ modified with $Ag_2O$ were prepared by sintering at $1200^{\circ}C$ for 4 h. The fractured surface of sintered pellets were examined by scanning electron microscopy(SEM). The dielectric constant, loss, and pyroelectric coefficient of the ceramics samples were determined. The dielectric and pyroelectric properties could be improved with the addition of small amount of $Ag_2O$ up to 0.2 mol%. The dielectric and pyroelectirc peak temperatures are continuously shifted to lower temperature with addition of small amounts of $Ag_2O$.

• Journal of Sensor Science and Technology
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• v.23 no.4
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• pp.224-228
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• 2014

The electrocaloric effect of 9/65/35 PLZT thin film fabricated by the sol-gel method, which has not been studied yet, was investigated for its structural, electrical properties as well as temperature change property. The relaxor ferroelectric property of 9/65/35 PLZT thin film was confirmed by examining its dielectric and electrical properties. The relaxor property can cause a more pronounced electrocaloric effect (ECE) in a wider temperature range than normal ferroelectric film. To avoid errors caused by using an indirect measurement method, the leakage current generated by increasing temperatures was minimized by using the optimal maximum electric field ($350kVcm^{-1}$) in the thin film. The largest temperature change ${\delta}T$ (0.23 K) and the electrocaloric strength ${\xi}$ (0.68 mkcm/kV), calculated by equations were obtained. The maximum field change ${\delta}E$ ($191kVcm^{-1}$) was in the vicinity of the curie temperature ($200^{\circ}C$).

• Journal of the Microelectronics and Packaging Society
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• v.20 no.4
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• pp.25-30
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• 2013

Pb-free ferroelectric $(Na_{0.5}Bi_{0.5})TiO_3$ (NBT) thin films were prepared by a modified sol-gel process. Their structural, dielectric and pyroelectric properties were investigated as a function of the excess Na/Bi ratio and the annealing temperature. In the case of thin films containing no excess Na and Bi, only partial amounts of the perovskite NBT were crystallized, where the films consisted mainly of the pyrochlore phase of $Bi_2Ti_2O_7$ for annealing conditions of $600{\sim}800^{\circ}C$. With increasing excess Na/Bi ratio, the proportion of the perovskite phase effectively increased due to the compensation of the volatile Na and Bi components. For a Na/Bi ratio of 2.0, the thin film with single NBT perovskite phase was obtained within XRD detection limit after annealing at $700^{\circ}C$ for 10 min and it showed the excellent dielectric properties, ${\varepsilon}r$ of ~550 and tan ${\delta}$ of 0.03. While these properties were degraded for Na/Bi ratio of 2.5 despite the existence of pure perovskite phase. The NBT thin film with Na/Bi ratio of 2.0 are also promising candidates for applications requiring pyroelectric devices because it was found to have pyroelectric coefficients of $1.3{\sim}7nC/cm^2K$ in the temperature range of $30{\sim}100^{\circ}C$.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1239-1243
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• 1997

A phase analysis in the solid solution of (1-x) PbFe1/2Nb1/2O3-xPbCo1/2W1/2O3 is conducted by dielectric properties, heat capacity and E-P hysteresis at x=0.1 interval. Lattice constants and superlattice intensity are analyzed by the x-ray diffraction, and the temperature - composition phase diagram is determined. The system is found to form a solid solution of perovskite structure throughout the entire composition range, but the nature of phase transitions changes from ferroelectric-paraelectric for $0{\leq}x{\leq}0.5$ to antiferroelectric-paraelectric for $0.6{\leq}x{\leq}1.0$. The transitions of ferroelectric-paraelectric and antiferroelectric-paraelectric for $0.2{\leq}x{\leq}0.5$ and for $0.6{\leq}x{\leq}0.8$, respectively, are diffuse, while those of the ferroelectric-paraelectric and the antiferroelectric-paraelectric for $0.0{\leq}x{\leq}0.1$ and $0.9{\leq}x{\leq}1.0$, respectively are sharp.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.186.1-189
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• 2001

Ferroelectric $Bi_{4-x}$La$_{x}$Ti$_3$O$_{12}$ (BLT)thin films with various compositions(x=0.65, 0.70, 0.75) were prepared on Pt//Ti/SiO$_2$/Si(100) substrate by metal-organic deposition. The electrical and structural characteristics of BLT thin films were investigated to develop ferroelectric thin films for capacitor layers of FRAM. After spin coating, thin films were annealed at $650^{\circ}C$ for 1hour in oxygen atomosphere. Scanning electron micrographs showed uniform surfaces composed of rod-like grains. The $Bi_{4-x}$La$_{x}$Ti$_3$O$_{12}$ (x=0.70) thin film capacitors with a Pt top electrode showed better ferroelectric properties than other films. At the applied voltage of 5V, the dielectric constant($\varepsilon$$_{r}$), dissipation factor(tan$\delta$),remanent polarization(2Pr), and coercive field(2Ec) of the $Bi_{4-x}$La$_{x}$Ti$_3$O$_{12}$ (x=0.70)thin films were about 272.54, 0.059, 32.4 $\mu$C/cm$^2$, 2Ec=119.9kV/cm. Also the capacitor did not show any significant fatigue up to 4.8$\times$10$^{10}$ read/write switching cycles.hing cycles.s.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05c
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• pp.93-96
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• 2002

In this study, PZT thin films were fabricated using sol-gel processing onto Si/$SiO_2$/Ti/Pt substrates. PZT sol with different Zr/Ti ratio(20/80, 30/70, 40/60, 52/48) were prepared, respectively. The films were fabricated by using the spin-coating method on substrates. The films were heat treated at $450^{\circ}C$, $650^{\circ}C$ by rapid thermal annealing(RTA). The preferred orientation of the PZT thin films were observed by X-ray diffraction(XRD), and Scanning electron microscopy(SEM). All of the resulting PZT thin films were crystallized with perovskite phase. The fine crystallinity of the films were fabricated. Also, we found that the ferroelectric properties from the dielectric constant of the PZT thin films were over 600 degrees, P-E hysteresis constant. And the leakage current densities of films were lower than $10^{-8}A/cm^2$. It is concluded that the PZT thin films by sol-gel process to be convinced of application for ferroelectric memory device.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.7
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• pp.599-603
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• 2003

Ferroelectric B $i_4$$_{-x}$N $d_{x}$ $Ti_3$ $O_{12}$ (BNdT) thin films with the composition(x=0.75) were prepared on Pt/Ti/ $SiO_2$(100) substrate by metal-organic deposition. The films were annealed by various temperatures from 550 to $650^{\circ}C$ and then the electrical and structural characteristics of BNdT films were investigated for the application of FRAM. Electrical properties such as dielectric constant, 2Pr and capacitance were quite dependent on the thermal heat treatment. The measured 2Pr value on the BNdT capacitor annealed at $650^{\circ}C$ was 56$\mu$C/$\textrm{cm}^2$ at an applied voltage of 5V. In fatigue characteristics value remained constant up to 8$\times$10$^{10}$ read/write switching cycles at a frequency of 1Mhz regardless of annealing temperatures.

• KIEE International Transactions on Electrophysics and Applications
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• v.3C no.2
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• pp.43-47
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• 2003

Lead zirconate titanate (PZT) thin films were fabricated by the pulsed laser ablation deposition (PLAD) method onto Pt/Ti/SiO$_2$/Si substrates. Crystalline phases as well as preferred orientations in PZT films were investigated by X-ray diffraction analysis (XRD). The well-crystallized perovskite phase and the (101) preferred orientation were obtained by two-step annealing at the conditions of $650^{\circ}C$, 1 hour. It was found that the temperature for the pulsed laser ablated PZT films annealed via a two-step annealing process can be reduced 20$0^{\circ}C$ compared to that of the conventional three-step annealing temperature profile for enhancing the transformation of the perovskite phase. The remanent polarization and the coercive field of this film were about 20 $\mu$C/$\textrm{cm}^2$ and 46 kV/cm, while the dielectric constant and loss values measured at 1 KHz were approximately 860 and 0.04, respectively. The interesting phenomena of this film, such as vertical shift in hysteresis curve, are also discussed.