High Endurance and Low Fatigue Effect of Bilayer Stacked Antiferroelectric/Ferroelectric Hf_<i>x</i>Zr_1-<i>x</i>O₂

Abstract

We fabricated ultrathin metal–insulator–metal capacitors and compared the performance of bilayer HZO consisting of 5-nm-thick antiferroelectric HZO (Zr = 75%) and 5-nm-thick ferroelectric HZO (Zr = 40%) with that of ferroelectric HZO (10-nm-thick) and antiferroelectric HZO (10-nm-thick). The bilayer HZO exhibited advantages of both antiferroelectricity and ferroelectricity, including a high dielectric constant (58), high remnant polarization (approximately <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$15~\mu \text{C}$ </tex-math></inline-formula> /cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ), a low coercive field, and excellent endurance (>10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sup> cycles). These results suggest that bilayer HZO is a promising candidate for use in nonvolatile memory devices.