Back-End of Line Compatible HZO/ZrO2 Ferroelectric Capacitor Achieving 2Pr of 51.1 μC/cm², High-k(~48.4), and Endurance Exceeding 1011 cycles under Low-voltage Operation

This study is motivated by the persistent challenge of developing dielectric (DE) materials that simultaneously satisfy the high dielectric constant of eDRAM-driven and robust ferroelectric (FE) properties required by FeRAM within a low thermal budget (≤400 °C) for application in Back-End of Line (BEOL) dual-mode cache/near memory processing units. Here, we address this challenge by a W/Hf_0.5Zr_0.5O₂(HZO)/ZrO₂/W structure ferroelectric capacitor and optimizing the thickness ratio of the ZrO₂ and HZO layers to construct near morphotropic phase boundary (MPB). The (HZ)6Z4 configuration, with a 4-nm ZrO₂ top layer and a 6-nm HZO layer, exhibited enhanced performance with remanent polarization (2P_r~51.1 μC/cm²) and dielectric constant (k~48.4) after RTP at 350 °C. The (HZ)6Z4 sample also demonstrates low-voltage operation (~1.7 V), high endurance (>10¹¹ cycles) due to a reduced coercive field (E_c~1.0 MV/cm), and fast polarization switching (~121 ns). These results show that (HZ)6Z4 nanostack can effectively balance the performance required for low-power BEOL dual-mode cache/near-memory processing units, paving the way for the development of next-generation advanced logic and memory devices.