• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 춘계학술대회 논문집 전자세라믹스 센서 및 박막재료 반도체재료 일렉트렛트 및 응용기술
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• pp.80-83
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• 2000

The post-annealing treatments on rf magnetron sputtered PZT($Pb_{1.05}(Zr_{0.52},\;Ti_{0.48})O_3$) thin films($4000{\AA}$) have been investigated for a structure of PZT/Pt/Ti/Coming glass(1737). Crystallization properties of PZT films were strongly dependent on RTA(Rapid Thermal Annealing) annealing temperature and time. We were able to obtain a perovskite structure of PZT at $650^{\circ}C$ and 10min. P-E curves of Pd/PZT/Pt capacitor demonstrate typical hysteresis loops. The measured values of $P_r$, $E_c$ were $8.1[{\mu}C/cm^2]$, 95[kV/cm] respectively. Polarization value decrease about 25% after $10^9$ cycles.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 D
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• pp.1986-1988
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• 1999

Ferroelectric lead zirconate titanate(PZT) thin films were prepared on various bottom electrodes by rf magnetron sputtering methode. The structural phase and surface morphology of the PZT thin films were largely affected by the bottom electrodes. P-E curves of PZT thin films deposited on Pt. $RuO_2$ and Ru/$RuO_2$ bottom electrode showed typical P-E hysteresis loop. The measure values of $P_r,\;E_c$ of the Ru/PZT/Ru/$RuO_2$ capacitor were $16.9{\mu}C/Cm^2$, 140kV/ cm, respectively. The Ru/PZT/Ru/$RuO_2$ capacitors were fatigue free uP to nearly $10^9$ switching cycle but Pt/PZT/Pt capacitor showed 34% degradation uP to $10^9$ switching cycle.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.321-322
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• 2006

The electrical properties of PZT thin film capacitor on TiN/W plug structure were investigated for high density ferroelectric memory devices. In order to enhance the ferroelectric properties of PZT capacitor, the process conditions of bottom electrodes were optimized. The fabricated PZT capacitor on TiN/W plug showed good remanent polarization, leakage current, and contact resistance of TiN/W plug, which were $33\;{\mu}C/cm^2$, $1.2{\times}10^{-6}\;A/cm^2$, and 5.3 ohm/contact, respectively.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.66-66
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• 2007

Lead zirconate titanate (PZT) is one of the most attractive perovskite-type materials for ferroelectric random access memory (FRAM) due to its higher remanant polarization and the ability to withstand higher coercive fields. We first applied the damascene process using chemical mechanical polishing (CMP) to fabricate the PZT thin film capacitor to solve the problems of plasma etching including low etching profile and ion charging. The $0.8{\times}0.8\;{\mu}m$ square patterns of silicon dioxide on Pt/Ti/$SiO_2$/Si substrate were coated by sol-gel method with the precursor solution of PZT. Damascene process by CMP was performed to pattern the PZT thin film with the vertical sidewall and no plasma damage. The polarization-voltage (P-V) characteristics of PZT capacitors and the current-voltage characteristics (I-V) were examined by change of process parameters. To examine the CMP induced damage to PZT capacitor, the domain structure of the polished PZT thin film was also investigated by piezoresponse force microscopy (PFM).

• 한국재료학회지
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• 제12권1호
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• pp.75-81
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• 2002

The ferroelectric properties of Pb(Zr,Ti)O$_3$[PZT] films degrade when the films with Pt top electrodes are annealed in hydrogen containing environment. This is due to the reduction activity of atomic hydrogen that is generated by the catalytic activity of the Pt top electrode. At the initial stage of hydrogen annealing, oxygen vacancies are formed by the reduction activity of hydrogen mainly at the vicinity of top Pt/PZT interface, resulting in a shift of P-E (polarization-electric field) hysteresis curve toward the negative electric field direction. As the hydrogen annealing time increases, oxygen vacancies are formed inside the PZT film by the inward diffusion of hydrogen ions, as a result, the polarization degrades significantly and the degree of P-E curve shift decreases gradually. The direction and the magnitude of the remnant polarization in the PZT film affect the motion of hydrogen ions which determines the degradation of polarization characteristics and the shift in the P-E hysteresis curve of the PZT capacitor during hydrogen annealing. When the remnant polarization is formed in the PZT film by applying a pre-poling voltage prior to hydrogen annealing, the direction of the P-E curve shift induced by hydrogen annealing is opposite to the polarity of the pre-poling voltage. The hydrogen-induced degradation behavior of the PZT capacitor is also affected by the internal field that has been generated in the PZT film by the charges located at the top interface prior to hydrogen annealing.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.139-140
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• 2006

PZT박막은 비휘발성 재료로 유전율이 높고 항전력이 작으면서 잔류 분극랑이 크기 때문에 적합한 특성을 가지고 FeRAM에 매력적인 물질이다. CMP(chemical mechanical polishing)는 기존의 회생막의 전면 식각 공정과는 달리 특정 부위의 제거 속도를 조절함으로써 평탄화 하는 기술로 wafer 전면을 회전하는 탄성 패드 사이에 액상의 Slurry를 투입하여 연마하는 기술이다. 본 논문에서는 CMP 공정으로 제조한 PZT박막 캐패시터에서 CMP 후처리공정(세척)의 유무 및 종류에 따라 피로특성에 대하여 연구하였다, PZT 박막의 캐패시터의 피로 특성을 연구한 결과 CMP 후처리공정 SC-l용액을 사용하여 세정공정을 하였을때 가장 향상된 PZT 캐패시터의 피로특성이 나타났다.

• 한국전기전자재료학회논문지
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• 제11권8호
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• pp.596-600
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• 1998

A method for the nondestructive read-out of the memory in ferroelectric thin films is demonstrated using the detection second harmonic currents introduced in the ferrolelectric capacitor as a response to an ac signal. The sign and phase of the second harmonic current depends on the polarized state +$P_r or -P_r$, The studied ferroelectric PZT thin film is found to have desirable features for the use as a memory element. This method and material seems as a promising approach for the nonvolatile memory storage.

• 한국재료학회지
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• 제3권1호
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• pp.19-27
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• 1993

RF magnetrom sputtering으로 52/48 PZT target을 사용하여 PZT thin film을 증착시킨후, furnace annealing을 실시하여 Si 기판에서는 55$0^{\circ}C$에서부터 안정상인 peroskite구조가 형성되었다. Si기판위에서는 후속열처리시 계면에 상당한 산화막층이 형성되었으며 TiN 기판위에서는 후속열처리시 TiN층은 사라지고 Ti$O_2$층이 형성되었다. Si$O_2$기판에서는 후속열처리후에도 안정한 PZT film을 형성시킬 수 있었다. As-depo.시에는 PZT film의 조성비가 균일하게 유지되었으나 75$0^{\circ}C$후속열 처리시에는 상당량의 Pb가 Si기판으로 diffusion하였으며 Si도 out-diffusion하였다. 전기적 특성은 10KHz에서 C-V를 측정결과 약 1300정도의유전상수 값이 나왔으나 후속열처리시 표면에 crack이 발생하였다.

• 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.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.705-706
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• 2010