Bi_3.25La_0.75Ti₃O₁₂ thin films on ultrathin Al₂O₃ buffered Si for ferroelectric memory application

We have investigated the physical and electrical properties of Bi _3.25La_0.75Ti₃O₁₂ (BLT) thin films on Pt/Ti/SiO₂/Si and on Al₂O₃(6nm)/Si, which are used for one-transistor-one-capacitor and one-transistor ferroelectric memory, respectively. The BLT thin films on both substrates show good capacitance-voltage characteristics and the same threshold voltage shift of 1.6 V at applied ±10 V bias. However, the leakage current of BLT on Al ₂O₃/Si at -100 kV/cm is two orders of magnitude lower than that on Pt. The comparable memory characteristics and much reduced leakage current of BLT on Al₂O₃/Si are the strong advantages as compared with BLT on Pt because it is directly related to switching energy and device scaling down.