• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.366-367
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• 2006

Different orientated SBN thin films were deposited by Ion Beam Sputtering, and electric properties were measured on each orientation. Ferroelectric $Sr_xBa_{1-x}Nb_2O_6$(SBN) has excellent electro-optic, photo-refractive, piezoelectric, pyroelectric properties. SBN thin film has been deposited by various method, of sol-gel, PLD, CVD, sputtering, etc.. To avoid lead pollution of Pb-system perovskite ferroelectric materials. SBN thin films were fabricated for pyroelectric IR sensor. Using the ceramic target of the same composition and Pt(100)/$TiO_2/SiO-2$/Si(100) substrate, crystallization and orientation behavior as well as electric properties of the films were examined. Seed layer and thin films thickness was controlled to observe the effect on preferred orientation. We measured I-V, C-V, P-E hysteresis to characterize electric-properties on each orientations.

• 한국세라믹학회지
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• 제29권11호
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• pp.870-876
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• 1992

Lead lanthanum zirconate titanate (PLZT, 6/65/35) powders, crack-free and dense thin films have been prepared by polymeric sol-gel process. Pyrolysis of the gel, crystallization and optical transmittance behavior of the PLZT thin film onto sapphire substrate have been studied. Esterification occurs during synthesis of PLZT complexation. Crystalline Pb phase was transiently formed near 450$^{\circ}C$. Content of perovskite phase in the films were increased with increasing thickness of film, but the kinetics of formation of perovskite phase in films was slower than that of powders. Transmittance of the films was decreased with increasing the temperature of heat treatment. Ferroelectric hysteresis loop measurements indicated increments of remanent polarization and coercive field for plenty more of perovskite phase.

• 한국세라믹학회지
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• 제35권3호
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• pp.294-302
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• 1998

$Pb_{1+x}$($Fe_{0.5}$$Nb_{0.5}$)$O_3$ films have been synthesized on Pt/Ti/$SiO_2$/Si substrates using rfmagnetron sputtering Concentration of Fe and Nb in the deposited films was adjusted to near stoichiometry through the control of target composition, Films deposited with adjusted to near stoichiometry showed better electrical properties such as dielectic and leakage characteristics. Crystallinity and dielectric constant increased with increasing excess PbO upto 9 mol% This study also showed that dielectric constant and leakage current characteristics improved by optimum content of $O_2$ flow during deposition.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.1829-1831
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• 2005

Ferroelectric $Bi_{3.25}Nd_{0.75}Ti_3O_{12}$(BNdT) thin films were proposed for capacitor of FeRAM. The BNdT thin films were grown on Pt/Ti $SiO_2/P-Si(100)$ substrates by the RF magnetron sputtering deposition. The dielectric properties of the BNdT were investigated by varying post-annealing temperatures. Increasing post-annealing temperature, the (117) peak was increased. An increase of rod type grains of BNdT films with increasing post-annealing temperature was observed by the Field Emission Scanning Electron Microscopy(FE-SEM). The dielectric constant and dielectric loss of the BNdT thin films with post-annealing temperature of $700^{\circ}C$ were 418 and 0.37, respectively.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.224-227
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• 1999

Ferroelectric Pb(Zr$\sub$0.52/Ti$\sub$0.48/)O$_3$ thin films were fabricated by pulsed laser deposition, mainly varying process conditions such as substrate temperature, oxygen pressure, and laser energy, PZT films annealed at more than 600$^{\circ}C$ were crystallized into pure perovskite phases regardless of deposition temperatures. Lower deposition temperature of 400$^{\circ}C$ accompanied with post-annealing at 650$^{\circ}C$ resulted in denser microstructures with extremely small grains compated to those of thin films annealed at higher deposition temperatures. Hysteresis curves of thin film with small grains exhibitied good squareness and low leakage characteristics.

• Journal of Electrical Engineering and Technology
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• 제2권3호
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• pp.391-395
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• 2007

MgO enhanced $(Ba_{0.6}Sr_{0.4})$ $TiO_3$ thick films have been fabricated by a tape casting and firing method for tunable devices on the microwave frequency band. In order to improve ferroelectric properties, the composite thick films enhanced with MgO on BST have been asymmetrically annealed by a focused halogen beam method. Dielectric constants of composite thick films are changed from 1050 to 1300 at 100 kHz after 60 s and 150 s annealing by the focused halogen beam. Even though no prominent changes were previously observed from the thick films before and after annealing in terms of chemical composition and surface morphology, it is clear that the average particle size of the thick films calculated by Scherrer's formula were increased by annealing. Furthermore, a strong correlation between particle size and dielectric constant of the composite thick films has been observed; dielectric constant increases with increased particle size. This has been attributed to the increased volume of ferroelectric domain due to increased particle sizes. As a result, the tuning range was improved by halogen beam annealing.

• Transactions on Electrical and Electronic Materials
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• 제5권6호
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• pp.223-226
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• 2004

The PZT thin films are one of well-known materials that has been widely studied for ferroelectric random access memory (FRAM). We etched the PZT thin films by $CF_{4}/(Cl_{2}+Ar)$ plasma and investigated improvement in etching damage by $O_{2}$ annealing. The maximum etch rate of the PZT thin films was 157 nrn/min and that the selectivity of the PZT thin films to Pt was 3.1 when $CF_{4}(30{\%})$ was added to a $Cl_{2}(80{\%})/Ar(20{\%})$ gas mixing ratio. To improve the ferroelectric properties of PZT thin films after etching, the samples were annealed for 10 min at various temperatures in $O_{2}$ atmosphere. After $O_{2}$ annealing, the remanent polarization of the asdeposited films was $34.6{\mu}/cm^{2}$ and the sample annealed at 650, 550, and $450^{\circ}C$ was 32.8, 22.3, and $18.6{\mu}/cm^{2}$, respectively. PZT thin films with $O_{2}$ annealing at $450^{\circ}C$ retained $77{\%}$ of their original polarization at 106 cycles. Also as the annealing temperature increased, the fatigue properties improved. And the leakage current was decreased gradually and almost recovered to the as-deposited value after the annealing at $450^{\circ}C$.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 C
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• pp.1562-1564
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• 2003

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.

• 한국전기전자재료학회논문지
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• 제22권1호
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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 $5.4{\times}10^{-9}\;A/cm^2$.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.1881-1883
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• 2005

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.