BEOL-Compatible Annealing-Free Hf_xZr_1-xO₂ Ferroelectric Device and Investigation of Cycle-Dependent Evolution Mechanisms

This work focuses on the performance optimization and cycle-dependent evolution mechanisms of low-temperature anneal-free hafnium-based ferroelectric devices. By modulating oxygen plasma power, effective synthesis of ferroelectric o-phase was achieved at processing temperatures <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\le$</tex-math></inline-formula>280 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∘</sup>C without the need for additional annealing process, compatible with CMOS back-end-of-line (BEOL) technology. The Hf<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>x</roman></sub>Zr<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>1</roman>-<i>x</i></sub>O<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>2</roman></sub> (HZO) film fabricated at 50-W power demonstrates a remarkable 2Pr of 50 μC/cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>2</roman></sup> and can withstand 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>10</roman></sup> polarization cycles without dielectric breakdown, exhibiting the best overall performance. Through combined macroscopic electrical characterization and microscopic polarization switching dynamics analysis, this work reveals a cycle-dependent evolution mechanism of ferroelectric properties and proposes a defect dynamic evolution model for anneal-free films. These results establish a foundational framework for designing next-generation embedded ferroelectric memories with low-temperature compatibility and ultrahigh reliability.