Back-End of Line Compatible HZO/ZrO ₂ Ferroelectric Capacitor Achieving 2P _<i>r</i> of 51.1 μC/cm ² , High- <i>k</i> (~48.4), and Endurance Exceeding 10 ¹¹ 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<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.5</sub>Zr<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.5</sub>O<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>(HZO)/ZrO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>/W structure ferroelectric capacitor and optimizing the thickness ratio of the ZrO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> and HZO layers to construct near morphotropic phase boundary (MPB). The (HZ)6Z4 configuration, with a 4-nm ZrO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> top layer and a 6-nm HZO layer, exhibited enhanced performance with remanent polarization (2<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">P_r</i>~51.1 μC/cm²) and dielectric constant (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i>~48.4) after RTP at 350 °C. The (HZ)6Z4 sample also demonstrates low-voltage operation (~1.7 V), high endurance (>10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sup> cycles) due to a reduced coercive field (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E_c</i>~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.