Excellent Ferroelectricity and Thermal Stability in Ce-Doped HfO ₂ Thin Films via Oxygen Vacancy Modulation

This study introduces cerium (Ce) doping as a controllable strategy to regulate oxygen vacancy ( V O ) concentration and stabilize the metastable orthorhombic phase in HfO 2 thin films. Ce dopants, with low defect formation energy and high solubility, promote V O formation and reduce the free energy of the orthorhombic phase, enhancing its stability. Guided by first-principles calculations, chemical solution deposition was used to prepare Ce-doped HfO 2 thin films, enabling precise control over V O concentration and addressing the limitations of traditional post-treatment methods that struggle to control V O . The optimized Ce 0.2 Hf 0.8 O 2 film exhibits a high remanent polarization (2 P r ≈ 45 μC/cm 2 ), a low coercive field ( E c ≈ 1.08 MV/cm), an endurance lifetime surpassing 10 10 cycles, excellent retention (94.8%), and stable ferroelectricity up to 200 °C. These findings highlight the potential of Ce-doped HfO 2 for high-temperature nonvolatile memory (NVM) applications and provide a pathway for designing other high-performance HfO 2 -based systems.