Annealing effect of the CeO2 buffer layers for PZT/CeO2/Si(111) structures

We demonstrate the ferroelectric behavior of PZT films grown on Si(111) substrates by using CeO2 buffer layers. CeO2 films were prepared by MBE (molecular beam epitaxy). Then they were subjected to an ex situ dry O-2 annealing in a furnace at 900 degrees C for 1 min or at 700 degrees C for 60 min. On these substrates, PZT (60 nm) were deposited. X-ray diffraction analysis showed that crystalline quality of both PZT and CeO2 films was better in the annealed samples. From the C-V measurement, a memory window in the PZT film on 900 degrees C-annealed CeO2 was derived to be 1.3 V. The leakage current density of PZT/CeO2/Si structures was also shown to decrease by 2 orders-of-magnitude at 1 MV/cm electric field.