• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.352-355
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• 2003

[ $Bi_{3.25}La_{0.75}Ti_3O_{12}$ ] (BLT) thin films were prepared by using metal organic decomposition method onto the LaNiO3 (LNO) bottom electrode. Both the structure and morphology of the films were analyzed by x-ray diffraction (XRD) and atomic force microscope (AFM). Even at low temperatures ranging from 450 to $650^{\circ}C$, the BLT thin films were successfully deposited on LNO bottom electrode and exhibited (117) orientation. The BLT thin films annealed as low as $600^{\circ}C$ showed excellent ferroelectricity, higher remanent polarization and no significant degradation of switching charge at least up to $5{\times}10^9$ switching cycles at a frequency of 100 kHz and 5 V. For the annealing temperature of $600^{\circ}C$, the remanent polarization $P_r$ and coercive field were $23.5\;{\mu}C/cm^2$ and 120 kV/cm, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.183-186
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• 2004

The dry etch behavior of PZT thin films was investigated in $BCl_3/N_2$ plasma. The experiments were carried out with measuring etch rates and selectivities of PZT to $SiO_2$ as a function of gas concentration and input rf power, chamber pressure. The maximum etch rate was 126 nm/min when 30% $N_2$ was added to $BCl_3$ chemistry. Also, as input rf power increases, the etch rate of PZT thin films was increased. Langmuir probe measurement showed the noticeable influence of $BCl_3/N_2$ mixing ratio on electron temperature and electron density as input rf power increased. The variation of Cl radical density as plasma parameters changed was examined by Optical Emission Spectroscopy (OES) analysis. According to X-ray diffraction (XRD) analysis, PZT thin films were damaged in plasma and an increase in (100), (200) and (111) phases showed the improvement in structure of the PZT thin films after the $O_2$ annealing process.

• Journal of the Microelectronics and Packaging Society
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• v.10 no.2
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• pp.7-12
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• 2003

The $Bi_{3.3}La_{0.7}O_{12}$(BLT) capacitors with Metal-Ferroelectric-Insulator-Silicon structure were prepared on $SiO_2/Si$ substrates by using sol-gel method. The BLT thin films annealed at $650^{\circ}C$ and $700^{\circ}C$ showed randomly oriented perovskite crystalline structures. The full with at half maximum (FWHM) of the (117) main peak was decreased from $0.65^{\circ}$ to $0.53^{\circ}$ with increasing the annealing temperature from $650^{\circ}C$ to $700^{\circ}C$, indicating the improvement in the crystalline quality of the film. In addition, the grain size and $R_rms$ , values were increased with increasing the annealing temperatures, showing the rough film surface at higher annealing temperatures. From the capacitance-voltage (C-V) measurements, the memory window voltage of the BLT film annealed at $700^{\circ}C$ was found to be about 0.7 V at an applied voltage of 5 V. The leakage current density of the BLT film annealed at $700^{\circ}C$ was about $3.1{\times}10^{-8}A/cm^2$.

• Journal of the Microelectronics and Packaging Society
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• v.9 no.4
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• pp.11-16
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• 2002

In this study, the dry etching characteristics of $SrBi_2Ta_2O_9$ (SBT) thin films were investigated by using ICP-RIE (inductively coupled plasma-reactive ion etching). The etching damage and degradation were analyzed with XPS (X-ray photoelectron spectroscopy) and C-V (Capacitance-Voltage) measurement. The etching rate increased with increasing the ICP power and the capacitively coupled plasma (CCP) power. The etch rate of 900$\AA$/min was obtained with 700 W of ICP power and 200 W of CCP power. The main problem of dry etching is the degradation of the ferroelectric material. The damage-free etching characteristics were obtained with the $Ar/C1_2/CHF_3$ gas mixture of 20/14/2 when the ICP power and CCP power were biased at 700 W and 200 W, respectively. The experimental results show that the dry etching process with ICP-RIE is applicable to the fabrication of the single transistor type ferroelectric memory device.

• Journal of the Korean Vacuum Society
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• v.15 no.2
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• pp.173-179
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• 2006

We have investigated structural and electrical properties of $PbZr_{0.3}Ti_{0.7}O_{3}$ (PZT) thin films deposited by pulsed laser deposition methods. PZT thin films have been deposited on $LaMnO_3$ (LMO) bottom electrodes with $LaAlO_3$ (LAO) substrates during different deposition times. High-resolution x-ray diffraction data have shown that all the PZT films and bottom electrodes are highly oriented. The thickness of each film is determined by field-emission scanning electron microscope. We have also observed root mean square roughness by using atomic force microscopy mode, and local polarization distribution and retention behavior of a ferroelectric domain by using piezoelectric force microscopy mode. A PZT/LMO structure has shown good ferroelectric and retention properties as the media for nano-storage devices.

• Journal of the Korean Ceramic Society
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• v.41 no.2
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• pp.170-175
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• 2004

The ferroelectric (Y $b_{x}$ $Y_{1-x}$)Mn $O_3$ thin films were fabricated by sol-gel method using Y-acetate, Yb-acetate, and Mn-acetate as raw materials. The stable (Y $b_{x}$ $Y_{1-x}$)Mn $O_3$ precursor solution (sol) was prepared through the reflux process with acetylaceton as a catalyst and coated on Si(100) substrate by spin coating. The heat treatment temperature and, Rw ($H_2O$/alkoxide moi ratio) dependence on crystallinity of thin films were studied. The lowest temperature for obtaining YbMn $O_3$phase and the optimum heat-treatment conditions were proved as at 7$50^{\circ}C$ and 80$0^{\circ}C$, respectively. The hexagonal YbMn $O_3$with c-axis preferred orientation could be obtained at Rw=1 condition. The remanent polarization for the thin films of x=0 or 1 was about 200 nC/㎤ while, for the specimens ot 0< x< 1, were 50∼100 nC/$\textrm{cm}^2$.

• Journal of the Korean Ceramic Society
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• v.39 no.9
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• pp.829-834
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• 2002

Ferroelectric properties of $ErMnO_3$ thin films deposited on Si(100) substrate using Sol-gel process with metal salts were investigated. $ErMnO_3$ thin films with a (001) preferred orientation were crystallized at 800$^{\circ}C$. The $ErMnO_3$ thin film post-annealed at 800$^{\circ}C$ for 1 h showed the dielectric constant(k) of 26 and the dielectric loss(tan ${\delta}$) of 0.032 at the frequency range from 1 to 100 KHz. The grain size of $ErMnO_3$ thin film post-annealed at 800 for 1 h was 10∼30 nm. The remanent polarization($P_r$) of the $ErMnO_3$ thin films increased with increasing (001) preferred orientation. The $ErMnO_3$ thin films post-annealed at 800$^{\circ}C$ for 1 h showed the remanent polarization($P_r$) of 400 nC/$cm^2$, with the increase of post-annealing time at 800$^{\circ}C$, the coercive field($E_c$) of thin films was lowered because the dense and homogeneous thin films were obtained.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.12
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• pp.1092-1098
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• 2006

The influence of the concentration of precursor solution and the number of solution coatings on the densification of the $Pb(Zr_xTi_{1-x})O_3$ (PZT) thick films was studied. PZT powder and PZT precursor solution were prepared by3 sol-gel method and PZT thick films were fabricated by the screen-printing method on the alumina substrates. The composition of powder and precursor solution were PZT(70/30) and PZT(30/70), respectively. The PZT precursor solution was spin-coated on the PZT thick films. A concentration of a coating solution was 0.5 to 2.0 mol/L[M] and the number of coating was repeated from 0 to 6. The XRD patterns of all PZT thick films shelved typical perovskite polycrystalline structure. The porosity of the thick films was decreased with increasing the number of coatings and 6-time coated films with 1.5 M showed the dense microstructure and thickness of about $60{\mu}m$. The relative dielectric constant of the PZT thick film was increased with increasing the number of solution coatings and the thick films with 1.5 M, 6-time coated showed the 698. The remanent polarization the 1.5 M and 6-time coated PZT thick films was $38.3{\mu}C/cm^2$.

• Proceedings of the Korean Vacuum Society Conference
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• 1995.02a
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• pp.61-61
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• 1995

• Proceedings of the Korean Ceranic Society Conference
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• 2000.04a
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• pp.55.1-55.1
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• 2000