Flexible Hf_0.5Zr_0.5O₂ ferroelectric thin films on polyimide with improved ferroelectricity and high flexibility

Flexible memory devices are promising for information storage and data processing applications in portable, wearable, and smart electronics operating under curved conditions. In this work, we realized high-performance flexible ferroelectric capacitors based on Hf_0.5Zr_0.5O₂ (HZO) thin film by depositing a buffer layer of Al₂O₃ on polyimide (PI) substrates using atomic layer deposition (ALD). The flexible ferroelectric HZO films exhibit high remnant polarization (P_r) of 21 μC/cm². Furthermore, deterioration of polarization, retention, and endurance performance was not observed even at a bending radius of 2 mm after 5,000 bending cycles. This work marks a critical step in the development of high-performance flexible HfO₂-based ferroelectric memories for next-generation wearable electronic devices.