Oxygen vacancy engineering for BEOL-compatible thickness-scaled Hafnia ferroelectrics

Driven by the application demands of intelligent computing and edge devices, Hafnia-based ferroelectric (FE) memories are evolving toward low-voltage operation and improved energy efficiency. Reducing the thickness of the FE layer is considered an effective approach to achieving these objectives. This study focuses on the critical issue of polarization degradation during thickness scaling of Hafnia-based FE films and suggests that oxygen vacancy concentration may be an important factor associated with this degradation. Based on this hypothesis, an oxygen vacancy regulation strategy is implemented in back-end-of-line-compatible FE capacitors with 6 nm Hf_0.5Zr_0.5O₂films, achieving low-voltage operation (1.2 V) and excellent endurance (2P_rof 22.2 μC cm^-2retained after 10¹⁰switching cycles). This study provides experimental support and a possible design guideline for Hafnia-based FE devices targeting applications at adv technology nodes.