• 한국전기전자재료학회논문지
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• 제16권9호
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• pp.795-800
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• 2003

The dielectric and piezoelectric properties of the xPb(A $l_{0.5}$N $b_{0.5}$) $O_3$-(1-x)Pb(Z $r_{0.52}$ $Ti_{0.48}$) $O_3$ [xPAN-(1-x)PZT] thin films by pulsed laser deposition (PLD) were investigated as a function of PAN contents. The effect of texture on dielectric and piezoelectric properties of the 0.05PAN-0.95PZT thin films having the highest piezoelectric constant( $d_{33}$) was studied more precisely. For 0$\leq$x$\leq$0.15 compositions in xPAN-(1-x)PZT thin films, the well-developed perovskite phase with (111) preferred orientation was obtained at the deposition temperature of 50$0^{\circ}C$. With increasing PAN content, remanent polarization and coercive field decreased. The dielectric constant increased with an increase of PAN content until it reached 1450 at $\chi$= 0.05, and then decreased for higher PAN content. The maximum points of dielectric constant coincides with the maximum points of the piezoelectric constant $d_{33}$.33/.33/././.

• 한국세라믹학회지
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• 제30권10호
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• pp.803-810
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• 1993

PbxZr0.4Ti0.6O3 thin films were prepared by reactive co-sputtering and annealed by RTA(Rapid Thermal Annealing) process. Effect of Pb content in PbxZr0.4Ti0.6O3 films on the phase transformation was intensively studied. It has been found out that depending on the Pb content as well as RTA temperature, crystal structure of PbxZr0.4Ti0.6O3 films change greatly. It turned out that transformation temperature for perovskite can be lowered and the width of transition temperature region was reduced by increasing Pb content in the film. And the lattice was expanded with increasing Pb content. With increasing RTA temperature, as-deposited phase was transformed into perovskite through three different transformation paths depending on Pb content. It was confirmed that activation energies for nucleation of perovskite structure are much larger than those of its growth.

• 한국세라믹학회지
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• 제36권10호
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• pp.1035-1039
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• 1999

Ferroelectric properties and reliability characteristics of(111) and (100) preferentially oriented tetragonal Pb(Zr0.2Ti0.8)O3 (PZT) thin film capacitors have been investigated as a function of the top electrode thickness. The (111) preferentially oriented film exhibits 180$^{\circ}$domain switching process with better squareness of hysterisis loop and abrupt change of small singal capacitance-voltage comparing to the (100) preferentially oriented film having 90$^{\circ}$ domain switching process. The domain swithcing process of tetragonal phase PZT is different from that of rhobohedral phase. The film with thinner top electrode shows less initial switching polarization due to less compressive stress but it exhibits better endurance characteristics due to enhancing partial switching region.

• 한국전기전자재료학회논문지
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• 제18권2호
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• pp.105-108
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• 2005

The Pb(Zr,Ti)O$_3$ thin films were fabricated with Pb(La,Ti)O$_3$ buffers in-situ onto Pt/Ti/SiO$_2$/Si substrates by pulsed laser deposition method. We have observed the increase of the remanent polarization using PLT buffers. The remanent polarization value of 33.4 $\mu$C/$\textrm{cm}^2$ and the coercive field value of 66.4 kV/cm were obtained when the PLT tufter was deposited for 15 seconds. Enhancement of the polarization is resulted from the enhanced orientation of PZT thin film because of the PLT buffet layer.

• 한국세라믹학회지
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• 제34권10호
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• pp.1060-1066
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• 1997

In this paper, the effects of La addition of PLZT thin film prepared by sol-gel method on the capacitor characteristics are investigated for gigabit generation DRAM applications. The addition of La on the PLZT capacitor results in a trade-off between charge storage density(Qc') and leakage current density(Jl). As La content increases, Qc' and permeability(εr) at 0V are reduced while Jl is significantly decreased. It is demonstrated that 5% La doping of PZT can substantially reduce Jl and also improve resistance to fatigue while incurring only minimal degradation of Qc'. Very low leakage current density (5×10-7 A/㎠ even at 125℃) and high charge storage density (100fC/㎛2) under VDD/2=1V conditions are achieved using 5% La doped PZT thin films for gigabit DRAM capacitor dielectrics. In addition, the fatigue and TDDB measurements indicate good reliability of the PLZT capacitors.

• 한국재료학회:학술대회논문집
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• 한국재료학회 1999년도 추계학술발표강연 및 논문개요집
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• pp.71-71
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• 1999

• 한국재료학회:학술대회논문집
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• 한국재료학회 1999년도 추계학술발표강연 및 논문개요집
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• pp.145-145
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• 1999

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2000년도 추계총회,초청강연,특별강연,연구발표회
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• pp.145.2-145
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• 2000

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2000년도 추계총회,초청강연,특별강연,연구발표회
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• pp.177.1-177
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• 2000

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부 C
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• pp.801-803
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• 1998

We investigated Pt and $RuO_2$ as a bottom electrode and PZT thin film for ferroelectric applications. XRD examination shows that a mixed phase of (111) and (200) Pt peak for the temperature ranged from RT to $200^{\circ}C$, and a preferred (111) orientation for the substrate temperature of $300^{\circ}C$. From the XRD and AFM results, we recommend the substrate temperature of $300^{\circ}C$, 80 W for the Pt bottom electrode growth. From the study of an oxygen partial pressure from 0 to 50%, we learned that only Ru metal was grown with $0{\sim}5%$, a mixed phase of Ru and $RuO_2$ for $10{\sim}40%$, pure $RuO_2$ at 50%. Having optimized the bottom electrode growth conditions, we employed two step process in PZT film capacitor: PZT film growth at the low substrate temperature of $300^{\circ}C$ and then post RTA anneal treatments. PZT films were randomly oriented on $RuO_2$ and (110) preferentially oriented on Pt electrode. Leakage current density of PZT film demonstrated two to three orders higher for $RuO_2$ bottom electrode. From C-V results we observed a dielectric constant of PZT film higher than 1200. This paper presents the optimized process conditions of the bottom electrodes and properties of PZT thin films on these electrodes.