M/Bi3.4La0.6Ti3O12/I/Si capacitors for the application in FEDRAM

The ferroelectric memory (FEM) capacitors were prepared by depositing lanthanum-doped Bi4Ti3012: Bi3.4La0.6Ti3O12 (BLT) thin films on Si and SiO2/Si substrates using an silicon dioxide as a buffer layer. The C-V characterization of M/BLT/Si and M/BLT/SiO2/Si capacitors were studied. It is found that the charges in silicon injected into BLT ferroelectric films, and p-n injection effect existed between the film and Si (F-S) interface, which changed the polarization state in FEM capacitors. The introduction of SiO2 buffer layer could decrease the charge injection effect, and the polarization storage of FEM capacitors could be realized. A physical model based on the consideration energy-band theory has been constructed in explaining the p-n injection effect.