Bi 3.25 La 0.75 Ti 3 O 12 thin films on ultrathin Al2O3 buffered Si for ferroelectric memory application

We have investigated the physical and electrical properties of ${\mathrm{Bi}}_{\text{3.25}}{\mathrm{La}}_{\text{0.75}}{\mathrm{Ti}}_3{\mathrm{O}}_{12}$ (BLT) thin films on ${\mathrm{Pt/Ti/SiO}}_2/\mathrm{Si}$ and on ${\mathrm{Al}}_2{\mathrm{O}}_3\text{(6\hspace{0.17em}}\mathrm{nm}\mathrm{)/}\mathrm{Si},$ 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 ${\mathrm{Al}}_2{\mathrm{O}}_3/\mathrm{Si}$ 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 ${\mathrm{Al}}_2{\mathrm{O}}_3/\mathrm{Si}$ are the strong advantages as compared with BLT on Pt because it is directly related to switching energy and device scaling down.