• Journal of the Korean Vacuum Society
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• v.8 no.3A
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• pp.231-237
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• 1999

$SrBi_{22.4}Ta_2O_9$ (SBT) thin films of 70~150 nm thickness were prepared on platinized silicon substrates by Liquid Source Misted Chemical Deposition (LSMCD) process, and their microstructure, feroelectric and leakage current characteristics were investigated. By annealing at $800^{\circ}C$ for 1 hour in oxygen ambient, SBT films were fully crystallized to the Bi layered perovskite structure without preferred orientation. The grain size of the LSMCD- derived SBT films was about 100nm, and was not varied with the film thickness. $2P_r$ and $E_c$ of the SBT films increased with decreasing the film thickness, and the 70nm-thick SBT film exhibited $2P_r$ of 17.8 $\mu$C/$\textrm{cm}^2$ and $E_c$ of 74kV/cm at applied voltage of 5V. Within the film thickness range of 70~150nm, the relative dielectric permittivity of the LSMCD-derived SBT film decreased with decreasing the film thickness. Leakage current densities lower than $10^{-7}\textrm{A/cm}^2$ at 5V were observed in the SBT films thicker than 125nm.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1434-1436
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• 1996

In this study, ferroelectric $PbTiO_3$ thin films were deposited on the Pt/$SiO_2$/Si substrate by Sol-Gel method. $PbTiO_3$ stock solution was made and spin-cooled at 4000[rpm] for 30[sec.]. Coated specimens were dried at $400[^{\circ}C]$ for 10[min.] and then annealed at $500{\sim}800[^{\circ}C]$ for 1 hour. Annealing temperature were examined to optimize micro structural and dielectric properties of the films. The ferroelectric perovskite phase was observed in the file annealed at $700[^{\circ}C]$ for 1 hour. In the case of $PbTiO_3$ thin films annealed at $700[^{\circ}C]$ for hour, dielectric constant and dielectric loss showed the good value of 324, 2.0[%], respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05c
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• pp.58-62
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• 2002

Pb($Zr_{0.52}Ti_{0.48}$)$O_3$ (PZT) thin films deposited on the Pt/Ti and Ru/$RuO_2$ bottom electrode by rf magnetron sputtering methode. Ru/$RuO_2$ bottom electrode deposited on the p-type wafer as Ru thickness by in-situ process. Our results show that all PZT films indicated perovskite polycrystalline structure with perferred orientation (110) and no pyrochlore phase is observed. A well-fabricated $RuO_2$/PZT/Ru(100nm)/$RUO_2$ capacitor showed a leakage current density in the order of $2.13{\times}10^{-7}A/cm^2$ as 100 kV/cm, a remanent polarization of 7.20 ${\mu}C/cm^2$, and a coercive field of 58.37 kV/cm. The results show that the new Ru/$RuO_2$ bottom electrodes are expected to reduce the degradation ferroelectric fatigue and excellent ferroelectric properties.

• Journal of the Korean Ceramic Society
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• v.39 no.4
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• pp.341-345
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• 2002

The effect of the Pt electrode and the $Pt-IrO_2$ hybrid electrode on the performance of ferroelectric device was investigated. The modified Pt thin films with non-columnar structure significantly reduced the oxidation of TiN diffusion barrier layer, which rendered it possible to incorporate the simple stacked structure of Pt/TiN/poly-Si plug. When a $Pt-IrO_2$ hybrid electrode is applied, PZT thin film properties are influenced by the thickness and the partial coverage of the electrode layers. The optimized $Pt-IrO_2$ hybrid electrode significantly enhanced the fatigue properties with minimal leakage current.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.71-74
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• 2000

Pt/Pb$TiO_3$/$SrTiO_3$/p-Si films were prepared by metallo-organic solution deposition(M0SD) method and investigated its structure and ferroelectric properties. Crystallinity of specimen as a funtions of post annealing temperature and the thickness of $SrTiO_3$(STO) buffer layer was studied using XRD and AFM. Based on C-V and P-E curve, $PbTiO_3$(PTO) capacitors showed good ferroelectric hysteresis arising from the polarization switching properties. When the thickness of ST0 buffer layer between PTO and Si substrate was 260 nrn and the post annealing temperature was $650^{\circ}C$, it was showed that production of the pyrochlore phase due to interdiffusion of Si into FTO was prevented. The dielectric constant of FTO thin films calculated from a maximum Cma in the accumulation region was 180 and the dielectric loss was 0.30 at 100 kHz frequency. The memory window in the C-V curve is 1.6V at a gate voltage of 5V.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.743-746
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• 2000

Metal-ferroelectric-insulator-semiconductor(MFIS) devices using Pt/$LiNbO_3$/Si structure were successfully fabricated. The dielectric constant of the AIN film calculated from the capacitance in the accumulation region in the capacitance-voltage(C-V) curve was about 8.2. The gate leakage current density of MIS devices using a aluminum electrode showed the least value of 1$\times$$1O^{-8}$A/$cm^2$ order at the electric field of 500kV/cm. The dielectric constant of $LiNbO_3$film on AIN/Si structure was about 23 derived from 1MHz capacitance-voltage (C-V) measurement and the resistivity of the film at the field of 500kV/cm was about 5.6$\times$ $1O^{13}$ $\Omega$.cm.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.11 no.2
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• pp.60-66
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• 2001

($Ba_x$$Sr_{1-x}$)$TiO_3$ (x=0.9, 0.7, 0.5) thin films were prepared on ITO-coated glass by sol-gel method. Perovskite phase formation temperature of BST thin films seemed to be higher than $600^{\circ}C$. Peaks of perovskite phase shift to high diffraction angles as the Sr/(Ba+Sr) ratio was increased, due to the smaller ionic size of $Sr^{2+}$ than $Ba^{2+}$ . As a heating temperature was increased, the grain became coarser. And as Sr/(Ba + Sr) ratio was increased, the grain became finer. Dielectric constants of the BST(50/50) thin film are higher and dielectric losses of that are lower than those of the others. Dielectric constant and dielectric loss of the BST(50/50) thin film were 652 and 0.042 at 1kHz, respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.5
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• pp.297-302
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• 2014

$La_{0.5}Sr_{0.5}CoO_3$ (LSCO) electrode thin films with a resistivity of ~ 1,600 ${\mu}{\Omega}cm$ were grown on c-$Al_2O_3$ (0001) substrate. $ZnSnO_3$ (ZTO) thin films with different thicknesses were directly grown on LSCO/c-$Al_2O_3$ (0001) substrates at a substrate temperature that ranged from 550 to $750^{\circ}C$ using Pulsed Laser Deposition (PLD). The secondary phase $Zn_2SnO_4$ occurred during the growth of ZTO films and it became more significant with further increasing substrate temperature. Polarization-electric-field (P-E) hysteresis characteristics, with a remnant polarization and coercive field of 0.05 ${\mu}C/cm^2$ and 48 kV/cm, respectively, were obtained in the ZTO film grown at $700^{\circ}C$ in 200 mTorr.

• Journal of the Korean Ceramic Society
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• v.33 no.10
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• pp.1101-1108
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• 1996

No-doped PZT thin films have been fabricated on Pt/Ti/SiO2/Si substrate using Sol-Gel technique. A fast annealing metho (three times of intermediate and final annealing) was used for the preparation of multi-coated 1800$\AA$ thick Nb-doped PZT thin films. As Nb doping percent was increased leakage current was lowered approximately 2 order but dielectic properties were degraded due to the appearance of pyrochlore phase and domain pinning. Futhermore the increase of the final annealing temperature up to 74$0^{\circ}C$lowered the pyrochlore phase content resulting in enhancing the dielectric properties of the Nb doped films. The 3%-Nb doped PZT thin films with 5% excess Pb showed a capacitance density of 24.04 fF/${\mu}{\textrm}{m}$2 a dielectric loss of 0.13 a switchable polarization of 15.84 $\mu$C/cm2 and a coercive field of 32.7 kV/cm respectively. The leakage current density of the film was as low as 1.47$\times$10-7 A/cm2 at the applied voltage of 1.5 V.

• Journal of the Korean Ceramic Society
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• v.42 no.4
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• pp.219-223
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• 2005

A promising capacitor, which has conformable step coverage and good uniformity of thickness and composition, is needed to manufacture high-density non-volatile FeRAM capacitors with a stacked cell structure. In this study, ferroelectric $Bi_{3.61}Nd_{0.39}Ti_3O_{12}$ (BNdT) thin films were prepared on $Pt(111)/TiO_2/SiO_2/Si$ substrates by the liquid delivery system MOCVD method. In these experiments, $Bi(ph)_{3}$, $Nd(TMHD)\_{3}$ and $Ti(O^iPr)_{2}(TMHD)_{2}$ were used as the precursors and were dissolved in n-butyl acetate. The BNdT thin films were deposited at a substrate temperature and reactor pressure of approximately $600^{\circ}C$ and 4.8 Torr, respectively. The microstructure of the layered perovskite phase was observed by XRD and SEM. The remanent polarization value (2Pr) of the BNdT thin film was $31.67\;{\mu}C/cm^{2}$ at an applied voltage of 5 V.