Orthorhombic-I Phase and Related Phase Transitions: Mechanism of Superior Endurance $(> 10^{14})$ of HfZrO Anti-ferroelectrics for DRAM Applications

Anti-ferroelectric HfZrO thin films exhibit favorable properties for the potential application in advanced embedded DRAM. However, their failure mechanisms are not well-understood yet. In this work, it was confirmed that the orthorhombic-I phase is directly attributed to the anti-ferroelectric characteristics in HfZrO films. Moreover, around the thickness of 6 nm, a reversible transition between the orthorhombic-I and tetragonal phases occurs, enhancing the stability of the anti-ferroelectric properties. Furthermore, a record-high measured endurance of $> \mathbf{10}^{\mathbf{14}}$ in anti-ferroelectric HfZrO thin films was experimentally demonstrated for the first time.