Characteristics of SrTiO₃ insulated layer in SBT ferroelectric thin films

Low temperature processing of SBT thin films with SrTiO3 (STO) seeded layer deposited onto Ir/SiO2/Si (MIM structure) and CeO2/Si (MFIS structure) substrate using MOD method was investigated. The Sr0.8Bi2.6Ta2O9 + x (SBT) thin films with a STO seeded layer on MIM structure showed prefer (115) orientation, well crystalline and lower crystal temperature than those without STO seeded layer. The SBT thin films with STO seeded layer on MFIS structure also showed prefer (115), (006) orientation and well crystalline SBT phase annealed at 700°C. The seeded layer, STO, effectively protected the evaporation of Bi through the Pt top electrode and diffusion of Bi into the Ir bottom electrode on MIM structure. It also can improve the crystallization of SBT phase, grain growth and lower crystallized temperature of SBT thin film. The memory window and leakage current densities of SBT thin films with STO seeded layers are improved significantly in comparison with those films without the STO seeded layer. In the MIM structure, the SBT thin film with STO seeded layer can decrease the leakage current density to 10-9 A/cm2 at 100 kV/cm. In the MFIS structure, the SBT thin film with STO seeded layer also can improve the memory window and lead to lower leakage current at low voltage.