• Journal of the Korean Ceramic Society
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• v.42 no.11 s.282
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• pp.763-769
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• 2005

Ferroelectric $ReMnO_3$(Re:Ho, Er) thin films were deposited on Si(100) substrate by Metal-Organic Chemical Vapor Deposition (MOCVD). Crystallinity and electric properties of $ReMnO_3$(Re:Ho, Er) thin films were investigated as a function of thermal heat treatment process, CHP (Conventional Heat-treatment Process) and RTP (Rapid Thermal Process). $ReMnO_3$(Re:Ho, Er) thin films prepared by RTP showed higher c-axis preferred orientation and homogeneous surface roughness than those prepared by CHP. The remnant polarization of ferroelectric hysteresis loop of $ReMnO_3$(Re:Ho, Er) thin films was strongly dependent on the c­axis preferred orientation of hexagonal single phase, and the leakage current characteristics of thin films were dependent on the homogeneity of grain size as well as surface roughness of thin films.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.1
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• pp.29-34
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• 2009

PLZT thin films were deposited on platinized silicon (Pt/$TiSiO_2$/Si) substrate by RF magnetron sputtering. A $TiO_2$ buffer layer was fabricated, prior to deposition of PLZT films. the layer was strongly affected the crystallographic orientation of the PLZT films. X-ray diffraction was performed on the films to study the crystallization of the films as various substrate temperatures (Ts). According to increasing Ts, preferred orientation of films was changed (110) plane to (111) plane. The ferroelectric, dielectric and electrical properties of the films were also investigated in detail as increased substrate temperatures. The PLZT films deposited at $400^{\circ}C$ showed good ferroelectric properties with the remnant polarization of $15.8{\mu}C/cm^2$ and leakage current of $5.4{\times}10^{-9}\;A/cm^2$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.10
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• pp.866-870
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• 1998

PLZT thin films were fabricated with different Zr/Ti ratios by pulsed laser deposition. PLZT films deposited on Pt/Ti/SiO$_2$/Si substrate. This PLZT thin films of 5000$\AA$ thickness were crystallized at $600^{\circ}C$, $O_2$ pressure 200m Torr. 2/55/45 PLZT thin film showed a maximum dielectric constant value of $\varepsilon$\ulcorner=1550 and dielectric loss was 0.03 at 10kHz. At 2/70/30 PLZT thin film, coercive field and remnant polarization was respectively 19[kV/cm], 8[$\mu$C/$\textrm{cm}^2$]. Raman spectroscopy results showed that the bands of spectra became broader as the amount of Zr mol% increased and two crystal phase coexisted at 2/55/45 PLZT film. Raman spectroscopy was useful for crystal structure analysis of PLZT thin films.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.3
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• pp.207-213
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• 2003

The Sr$\_$0.7/Bi$\_$2.6/Ta$_2$O$\_$9/(SBT) thin films are deposited on Pt-coated electrode(Pt/TiO$_2$/SiO$_2$/Si) using RF magnetron sputtering method. The structural and electrical properties of SBT capacitors were influenced with annealing atmosphere. In the XRD pattern, the SBT thin films in all annealed atmosphere had (105) orientation. In the SEM images, Bi-layered perovskite phase was crystallized in all annealing atmosphere and grain largely grew in oxygen annealing atmosphere. The maximum remnant polarization and the coercive electric field in oxygen annealing atmosphere are 12.40[${\mu}$C/cm$^2$] and 30[kV/cm] respectively. The dielectric constant and leakage current density of capacitors annealed oxygen atmosphere are 340 and 2.13${\times}$10$\^$-9/ [A/cm$^2$] respectively. The fatigue characteristics of SBT capacitors did not change up to 10$\^$10/ switching cycles.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.217-220
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• 2000

The SrBi$_2$Ta$_2$O$\_$9/(SBT) thin films are deposited on Pt-coated electrode(Pt/TiO$_2$/SiO$_2$/Si) using RF sputtering method. The SBT thin films deposited on substrate at 400-500[$^{\circ}C$]. SBT thin film deposited on Pt-coated electrodes have the cubic perovskite structure and polycrystalline state. With increasing annealing temperature from 600[$^{\circ}C$] to 850[$^{\circ}C$], flourite phase was crystallized to 650[。 and Bi-layered perovskite phase was crystallize ed above 700[$^{\circ}C$]. The maximum remnant polarization and the coercive electric field is 11.73[${\mu}$C/$\textrm{cm}^2$], 85[kV/cm] respectively at annealing temperature of 750[$^{\circ}C$]. The fatigue characteristics of SBT thin films deposited on Pt/TiO$_2$/SiO$_2$/Si substrate did not change up to 10$\^$10/ switching cycles.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.10
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• pp.615-619
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• 2015

In this study, in order to develop the composition ceramics with the excellent electrocaloric properties, 8/65/35 PLZT ceramics were fabricated by the conventional solid-state method with the addition of $Bi_2O_3$, CuO, $Li_2CO_3$ and the variation of sintering temperature from $930^{\circ}C$ to $990^{\circ}C$. The XRD pattern of all specimens indicated general perovskite structure and the rhombohedral phase were observed. Curie temperature ($T_c$) of all specimens was observed in the vicinity of about $190^{\circ}C$. Density, coercive field and remnant polarization of the specimen sintered at $950^{\circ}C$ was $7.55g/cm^3$, 8.895 kV/cm, $11.22{\mu}C/cm^2$, respectively. EC effect of PLZT ceramics was measured by indirect method and the temperature change ${\Delta}T$ due to the electrocaloric effect was calculated by Maxwell's relations. ${\Delta}T$ of ceramic sintered at $950^{\circ}C$ was $0.21^{\circ}C$ under application of 40 kV/cm at $190^{\circ}C$.

• Korean Journal of Materials Research
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• v.18 no.2
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• pp.98-102
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• 2008

The ferroelectric properties of UV irradiated and non-irradiated PZT films prepared via photochemical metal-organic deposition using photosensitive precursors were characterized. Fourier transform infrared spectroscopy showed that complete removal of organic groups was possible through UV exposure of the spin-coated PZT precursor films at room temperature. The measured remnant polarization values of UV-irradiated and non-irradiated PZT films after annealing at $650^{\circ}C$ were 29 and $23\;{\mu}C/cm^2$, respectively. The UV irradiation was found to be effective for the enhancement of the <111> growth orientation and ferroelectric property of PZT film and in the direct patterning in the fabrication of micro-patterned systems without dry etching.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.3
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• pp.229-233
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• 2019

Pure $BiFeO_3$ (BFO) and (Eu, V) co-doped $Bi_{0.9}Eu_{0.1}Fe_{0.975}V_{0.025}O_{3+{\delta}}$ (BEFVO) thin films were deposited on $Pt(111)/Ti/SiO_2/Si(100)$ substrates by chemical solution deposition. The effects of co-doping were observed by X-ray diffraction, Raman spectroscopy, and scanning electron microscopy (SEM). The electrical properties of the BEFVO thin film were improved as compared to those of the pure BFO thin film. The remnant polarization ($2P_r$) of the BEFVO thin film was approximately $26{\mu}C/cm^2$ at a maximum electric field of 1,190 kV/cm with a frequency of 1 kHz. The leakage current density of the co-doped BEFVO thin film ($4.81{\times}10^{-5}A/cm^2$ at 100 kV/cm) was two orders of magnitude lower than of that of the pure BFO thin film.

• Journal of the Korean Ceramic Society
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• v.39 no.12
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• pp.1128-1132
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• 2002

$ReMnO_3$(Re:Y, Ho, Er) thin films were prepared by MOCVD method available to non-volatile memory device with MFS-FET structure. $ReMnO_3$ thin films were deposited on the Si(100) substrate at 700${\circ}C$ for 2h. When the films were post-annealed at 900${\circ}C$ for 1h in air, the single phase of hexagonal $ReMnO_3$ thin films were detected. Ferroelectric properties of $ReMnO_3$ thin films were dependent on the degree of c-axis orientation in the single phase of hexagonal structure and remnant polarization (Pr) of $YMnO_3$ thin films with high degree of c-axis orientation was 105 nC/$cm^2$. Leakage current density was dependent on the grain size of microstructure and that of $YMnO_3$ thin films with grain size of 100∼150 nm was $10^{-8}$ A/$cm^2$ at applied voltage of 0.5 V.

• Journal of the Korean Ceramic Society
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• v.49 no.3
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• pp.266-271
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• 2012

The effect of $Bi(Mg_{1/2}Sn_{1/2})O_3$ (BMS) modification on the crystal structure, ferroelectric and piezoelectric properties of $Bi_{1/2}(Na_{0.8}K_{0.2})_{1/2}TiO_3$ (BNKT) ceramics has been investigated. The BMS-substitution induced a transition from a ferroelectric (FE) tetragonal to a nonpolar pseudocubic phase, leading to degradations in the remnant polarization, coercive field, and piezoelectric coefficient $d_{33}$. However, the electric-field-induced strain was significantly enhanced by the BMS substitution-induced phase transition and reached a highest value of $S_{max}/E_{max}$ = 633 pm/V under an applied electric field of 6 kV/mm when the BMS content reached 6 mol%. The abnormal enhancement in strain was attributed to the field-induced transition of the pseudocubic symmetry to other asymmetrical structure, which was not clarified in this work.