Research On Domain Structure Control And Modification Of The PZT Ferroelectric Thin Films

Owing to their high remanent polarization,fast switching behavior,and controllable preparation process,the lead zirconate titanate[Pb?Zr,Ti?O₃?PZT?]ferroelectric thin films are considered to be one of the most promising materials for non-volatile ferroelectric random access memory?FRAM?.It is required that the ferroelectric thin film must have good reliability and good ferroelectric performance within a certain temperature range,because heat generated by energy dissipation during performs multiple repeated read and write processes of the FRAM.This paper studies the preparation,reliability verification and modification of PZT ferroelectric thin films.In this work,Pb(Zr_0.3Ti_0.7)O₃?PZT?ferroelectric thin films were prepared on Pt/TiO₂/SiO₂/Si substrate and conductive metal oxide LNO substrate by the sol-gel method.In addition,Mn doping modification of the PZT thin films on Pt/TiO₂/SiO₂/Si substrate was studied.The domain structure of the PZT thin films were characterized by the piezoelectric force microscope?PFM?,and the microstructure and electrical properties of the PZT film were analyzed.The PZT/Pt thin films had good ferroelectric properties and reliability at 20-70?.For Mn-doped PZT thin films,a small amount of Mn replaced the A-site(Pb²⁺)to form donor doping.When the doping concentration exceeds 1%,Mn replaced the B-site(Zr⁴⁺/Ti⁴⁺)to form acceptor doping.The remanent polarization?P_r?,coercive voltage?V_c?and piezoelectric constant(D_max)of 1%Mn-doped PZT thin films increased by 125%,28.1%and 65%,respectively.For the PZT thin films grown by LNO bottom electrode,the domain structure of the PZT/LNO thin films were more diverse and complicated,and there were obvious stripe domain structures in the plane.Compared with the traditional Pt-based PZT/Pt thin films,V_c was reduced by 9.28%,P_r was increased by 69.173%,and D_max was increased by 78.36%.This investigation suggests that the PZT ferroelectric thin films prepared by sol-gel method are reliable in the temperature range of 20-70?.Mn-doped can effectively improve the residual polarization and piezoelectric effect of the PZT thin films,but the increase of V_c is not conducive to the application of materials.In addition,LNO instead of Pt as the bottom electrode can enhance the ferroelectric and piezoelectric properties of PZT thin films,and reduce the polarization reversal voltage on the basis of ensuring the enhancement of polarization intensity.The research provides guidance for PZT thin films material to be used in the FRAM.