Improvement of remanent polarization of CeO2–HfO2 solid solution thin films on Si substrates by chemical solution deposition
Shuaizhi Zheng, Zidong Zhao, Zhaotong Liu, Binjian Zeng, Lu Yin, Qiangxiang Peng, Min Liao, Yichun Zhou
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.