Ferroelectricity in Ce_0.2-HfO₂ films around 500 nm in thickness

CeO₂-HfO₂ solid solution thin films (Hf_1-xCe_xO₂) were deposited on Pt(111)/TiO₂/SiO₂/Si(100) substrates using the chemical solution deposition method. This study investigates the influence of CeO₂ content and annealing temperature on the structure and ferroelectric properties of Hf_1-xCe_xO₂ films. Ferroelectric behavior is demonstrated in polycrystalline Hf_0.80Ce_0.20O₂ films with thicknesses ranging from 163 to 524 nm. And the structure of the films is analyzed using glancing incidence X-ray diffraction. The comprehensive results indicate that Hf_0.80Ce_0.20O₂ films annealed at 850 °C exhibit excellent ferroelectricity. Square hysteresis loops associated with the ferroelectric orthorhombic phase are observed, even in the 524-nm-thick film. The remnant polarization (P_r) and coercive field (E_c) range from 16 to 18 μC/cm² and 1100–1250 kV/cm, respectively, under a maximum applied electric field of 2 MV/cm for all Hf_0.80Ce_0.20O₂ films. Furthermore, the film presents thickness-insensitive characteristic. The current work paves the new way to design high-performance thick HfO₂-based ferroelectric films.