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

Abstract

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.

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

“…In the case of Pb excess compositions, however, Ce doping decreases the number of the oxygen vacancies, as explained by Eq. (7). Because the mobility of the oxygen vacancies is one of the main mechanisms of charge transport and therefore one of the main contributors to the leakage current in FE/AFE thin films, any dopant decreasing the concentration of oxygen vacancies will consequently cause a drop in the leakage current.…”

“…(6) and decreasing the concentration of oxygen vacancies according to Eq. (7). However, there will still be oxygen and lead vacancies present in the films and these vacancies will act as traps for electrons and holes.…”

“…3 Another recent application reported in the literature for AFE thin films is their possible use as buffer layers to improve FE fatigue behavior of lead zirconate titanate (PZT)-based FE thin films with platinum electrodes. [4][5][6][7] In contrast to FEs, the internal stresses in the AFE phase are much smaller due to the 1801 polarization switching and the leakage current characteristics of lead zirconate are much better compared with PZT films. 4 In our previous articles on PZ thin films, the optimization of processing conditions and the relationship between crystallographic orientation and FE properties were investigated and reported in detail.…”