Comparative investigating the properties of Pb-based multilayer ferroelectric thin films for FeRAM

The PbZr_0.3Ti_0.7O₃(PZT) thin film and multilayer PbZr_0.3Ti_0.7O₃/PbTiO₃(PZT/PT), PbTiO₃/PbZr_0.3Ti_0.7O₃/ PbTiO₃(PT/PZT/PT) thin films were prepared by a Sol-Gel method on the Pt(111)/Ti/SiO₂/Si(100) substrate for FeRAM application. The microstructure, ferroelectric, fatigue, dielectric, and leakage current properties of these thin films were investigated. The results indicate that the multilayer PT/PZT/PT thin film have a better ferroelectric, fatigue, dielectric and leakage current density properties. Its remanent polarization P_r reaches a maximum value of 21.2 μC/cm² and the coercive field E_c gets to a minimum value of 64.2kV/cm. After 10¹⁰ cycles, it still has more than 80% remnant polarization. The PT/PZT/PT thin film exhibits lower dielectric constant and lower dielectric loss, which is beneficial for FeRAM application. It also has the lowest leakage current density. The leakage current mechanism of the PZT, PZT/PT and PT/PZT/PT thin films is correlated to the microstructure and can be modeled in terms of GBLC and SCLC theory. The microstructure and electric properties of these films are correlated. The double-sided PT seed layers enhance not only the microstructure but also the electric properties. It is evident that the PT/PZT/PT multilayer thin film is a promising candidate for FeRAM application.