Improvement of remanent polarization of CeO2–HfO2 solid solution thin films on Si substrates by chemical solution deposition

Abstract

CeO2–HfO2 solid solution thin films, Hf1−xCexO2, are fabricated on n+-Si(100) substrates by the chemical solution deposition method. The effects of the CeO2 content and annealing temperature on the structure and ferroelectric properties of Hf1−xCexO2 are studied. The structural properties are investigated by glancing incidence x-ray diffraction and high resolution transmission electron microscopy, while the chemical states are examined by x-ray photoelectron spectroscopy. The results reveal that the admixture of CeO2 could effectively induce the ferroelectric phase. For Hf0.85Ce0.15O2 fabricated at an annealing temperature of 800 °C, an enhanced remanent polarization (Pr) of ∼20 μC/cm2 (after correction for leakage and parasitics) could be attained. Moreover, Hf0.85Ce0.15O2 demonstrates good endurance behavior, that the polarization does not show obvious degradation over 1 × 109 bipolar switching cycles, at an electric field of 2.9 MV/cm and a frequency of 100 kHz. This work highlights the importance of CeO2–HfO2 solid solution films in HfO2-based ferroelectric thin films.