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 O₂ annealing in a furnace at 900 °C for 1 min or at 700 °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 °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.