Improving fatigue resistance of Pb(Zr,Ti)O3 thin films by using PbZrO3 buffer layers

Journal of the American Ceramic Society

Shiosaki

2009

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Undoped and cerium (Ce)‐doped (1 and 5 mol%) antiferroelectric thin films were obtained by a sol–gel process. All lead zirconate, PbZrO3 (denoted as PZ), films crystallized in the perovskite phase with a full [111] pseudocubic orientation and with a uniform microstructure. X‐ray photoelectron spectroscopic investigations revealed that the oxidation state of Ce is 3+ leading to an A‐site donor doping. Ce doping causes a decrease in the dielectric constant from 200 to 155 and an increase in the forward switching fields from 275 to 296 kV/cm. However, it also leads to a significant decrease in the leakage current density and this effect is more pronounced for the 5% doping case, where an order of magnitude lower leakage current is obtained compared with the undoped PZ. Analyses of leakage current behavior indicate dominance of a space charge limited current type leakage current and also a possible contribution from a Poole–Frenkel type emission in certain temperature or field regimes.

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Investigation of the Effect of Cerium Doping on the Electrical Properties and Leakage Current Behavior of Lead Zirconate Thin Films Derived by the Sol–Gel Method

Journal of the American Ceramic Society

Shiosaki

2009

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“…Details of this process are discussed in another report. 17) Initially, stoichiometric PbZrO 3 powder was used as the target; however, elemental analysis of all the samples prepared from this target under various conditions indicated an excessive lead content. Therefore, 50% excess ZrO 2 was added to the stoichiometric PZ powder target.…”

Section: Preparation Of Pz Buffer Layersmentioning

confidence: 99%

Increased Fatigue Endurance in Pb(Zr,Ti)O₃ Thin Films through Use of PbZrO₃ Buffer Layers

Uchiyama

et al. 2006

jjap

Thin PbZrO 3 (PZ) films were investigated as a buffer layer to improve fatigue endurance of Pb(Zr 0:45 Ti 0:55 )O 3 (PZT) thin films. The PZ thin films were deposited on Pt ð111Þ /Ti/SiO 2 /Si ð100Þ substrates by RF magnetron sputtering from a loose powder target containing a mixture of PbZrO 3 and ZrO 2 powders. The PZT thin films on the PZ buffer layer were obtained by sol-gel spin coating. The PZ buffered PZT films had well crystallized, uniform and dense microstructure with partial (111) orientation. The P-E hysteresis measurements indicated comparable or slightly lower remnant polarization values (2P r ¼ 50 { 70 mC/cm 2 ) and higher coercive field levels compared to unbuffered film (2P r ¼ 66 mC/cm 2 ). The PZ buffered films displayed an asymmetric leakage current. The fatigue endurance of PZT thin films with PZ buffer layers was superior compared to the unbuffered counterpart with fatigue-free behavior observed up to 10 9 switching cycles.

“…[9][10][11] We have also recently reported obtaining PZT thin films with increased fatigue endurance through the use of lead zirconate, PbZrO 3 (PZ), buffer layers between the film and the bottom electrode. 12,13) The merits of PZ and the reasons for selecting this material as a buffer layer have been discussed in previous reports. 12,13) Different from some of the buffer layers reported in the literature such as (Ba 0:5 Sr 0:5 )TiO 3 (BST), 10) SiO 2 , 11) or Bi 4 Ti 3 O 12 (BiT), 11) lead zirconate is a Pb containing low-dielectric constant material with structural and compositional similarities to PZT.…”

Section: Introductionmentioning

confidence: 99%

Fatigue Behaviour of Pb(Zr,Ti)O₃/PbZrO₃ Multilayer Ferroelectric Thin Films

Uchiyama

et al. 2006

jjap

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Fatigue behaviour of Pb(Zr 0:45 Ti 0:55 )O 3 (PZT) thin films on Pt ð111Þ /Ti/SiO 2 /Si ð100Þ substrates with PbZrO 3 (PZ) buffer layers were investigated. Two different buffer layer configurations were studied: bottom-and top-only buffer layers. The PZ buffer layers were obtained by RF magnetron sputtering of a loose powder target containing a mixture of PbZrO 3 and ZrO 2 powders. The PZT thin films were prepared by sol-gel spin coating method. All of the films had well-crystallized, uniform and dense microstructure with full (111) orientation. The bottom buffer layers influenced the nucleation and grain growth of the upper PZT layers creating a bimodal grain size distribution. Secondary ion mass spectrometry (SIMS) elemental depth profiles indicated that a PZ buffer layer led to well-defined and sharp composition profiles. The P-E hysteresis measurements indicated comparable remnant polarization values (2P r ¼ 40 { 50 mC/cm 2 ) and coercive field levels (2E c ¼ 150 {180 kV/cm) with un-buffered film. The fatigue endurance of PZT thin films with PZ buffer layers was superior than the un-buffered counterpart. A fatigue-free behaviour was observed up to 10 9 switching cycles.