UC Berkeley

In recent years, the escalating demand for computing has necessitated the discovery of novel materials to power the next generation of logic and memory devices. Among these materials, ferroelectric hafnia (Hafnium Zirconium Oxide or HZO) stands out as a promising candidate. This thesis delves into the multifaceted realm of thin film ferroelectric HZO, spanning from deposition processes to the analysis of switching and fatigue behaviors. The study utilizes two distinct material systems: HZO/pyrochlore for fundamental investigations and HZO/La0.67Sr0.33MnO3 for practical applications, including Ferroelectric Tunnel Junctions (FTJ), enabling a comprehensive exploration.Chapter 3 focuses on epitaxial HZO with pyrochlore electrodes, revealing strain's role in stabilizing HZO's polar orthorhombic phase. It notes the high switching field in pure epitaxial HZO, hints at an order-disorder phase transition, and introduces a single-crystal ferroelectric epitaxial HZO system. Chapter 4 delves into the fatigue bahavior of hafnia, showing oxygen intercalation and defect chemistry's impact on stabilizing the orthorhombic phase, crucial for endurance behavior. Chapter 5 highlights Tunnel Electro-Resistance effects in HZO-based Ferroelectric Tunnel Junctions and the scale-free property of ferroelectric HZO, promising for high-density memory applications. In summary, this thesis advances HZO-based ferroelectric materials' understanding, laying the groundwork for future research in advanced computing and memory systems.