Balancing ferroelectricity and endurance in Hf _0.5 Zr _0.5 O ₂ thin films through mixed-oxygen atomic layer deposition

Abstract Simultaneous optimization of remanent polarization (2 Pr ) and long-term endurance remains a critical challenge for Hf _0.5 Zr _0.5 O ₂ (HZO)-based ferroelectric thin films in next-generation non-volatile memory technologies. Here, we introduce a sequenced mixed-oxidant atomic layer deposition (ALD) process that employs an initial deionized H ₂ O pulse followed by controlled O ₃ exposure to decouple the inherent trade-off between strong ferroelectricity and reliability. The optimized Mix-10 s sample delivers a high 2 Pr ≈ 48 μ C cm ⁻² in ∼10 nm-thick films, accompanied by wake-up-free characteristics and outstanding cycling stability, retaining 98.9% of the pristine polarization after 10 ⁹ bipolar switching cycles with minimal fatigue. Structural and electrical characterizations, including grazing-incidence x-ray diffraction, transmission electron microscopy, piezoresponse force microscopy, and switching current analysis, reveal a cooperative defect-engineering mechanism. The initial H ₂ O pulse introduces a moderate oxygen vacancy concentration that lowers the kinetic barrier for stabilizing the ferroelectric orthorhombic phase, whereas the subsequent O ₃ pulse removes residual carbon and hydrogen impurities and suppresses excessive vacancy accumulation, thereby mitigating domain wall pinning and leakage. This hybrid oxidant ALD approach provides a scalable and complementary metal-oxide-semiconductor compatible pathway toward high-polarization, fatigue free hafnia-based ferroelectrics for advanced memory and neuromorphic applications.