Effect of Ba(Mg_1/3Nb_2/3)O₃ buffer layer on electrical properties of PZT-based films

Pb[Nb_x(Zr_0.52Ti_0.48)_1−x]O₃ (PNZT) thin films were deposited on Pt/Ti/SiO₂/Si(100) by the sol–gel method using Ba(Mg_1/3Nb_2/3)O₃ (BMN) buffer layer. The effects of Nb doping and BMN buffer layer on fatigue endurance and ferroelectric properties of PZT thin film were investigated. The optimum ferroelectric properties of PNZT film: P_r = 43.4 µC/cm², E_c = 29.3 kV/cm and J = 2.73 × 10^− 6 A/cm² were obtained by doping 3 mol% Nb in PZT film. After 10¹⁰ cycles, the P_r of PZT film reduces by 50%. After 10¹² cycles, the P_r of PNZT film only reduces by 20%. The reason for enhanced ferroelectric properties and fatigue endurance of PNZT thin film is that Nb doping effectively prevents the generation of oxygen vacancies. The P_r of the PNZT/BMN film remains 85% after 10¹⁰ cycles, and it remains stable even till to 10¹² cycles. Moreover, the leakage current of PNZT/BMN film is 5.40 × 10^− 7 A/cm² under 100 kV/cm electric field, which is about one order of magnitude lower than that of PNZT (2.73 × 10^− 6 A/cm²). The effect of BMN on improving the fatigue endurance and ferroelectric properties of PNZT thin film could be ascribed to blocking of Pt diffusion at the PNZT–Pt interface. Moreover, PNZT/BMN film with excellent ferroelectric and fatigue endurance shows the promising application in FeRAM.