Low Polarization Loss of Long Endurance on Scavenged Ru-Based Electrode Ferroelectric Hf0.5Zr0.5O₂ by Optimizing TiN x Interfacial Capping Layer and Its Fatigue Mechanism

Double remnant polarization (2P <tex-math notation="LaTeX">ᵣ) </tex-math> values are increased significantly from <tex-math notation="LaTeX">17.1~μ C </tex-math> /cm2 to <tex-math notation="LaTeX">39.9~μ C </tex-math> /cm2 by reducing the TiNx interfacial capping layer (ICL) thickness from 3 nm to 1 nm in the Ru/TiNx/Hf <tex-math notation="LaTeX">_0.5 </tex-math> Zr{0}.{5}O2(HZO)/TiN structure owing to lower monoclinic (m) phase with respect to orthorhombic (o) plus rhombohedral (r) phases. These phases are observed by geometrical phase analysis (GPA) of high-resolution transmission electron microscope (HRTEM) images. An optimized 2 nm TiNx ICL ferroelectric memory shows lowest fatigue and mechanism is higher m-phase starting to grow from the HZO/TiN BE interface, which is evidenced in the HRTEM image after long endurance of <tex-math notation="LaTeX">10^11 </tex-math> cycles under high ±4 MV/cm, <tex-math notation="LaTeX">0.5~μ s </tex-math> (remaining higher 2Pr value of <tex-math notation="LaTeX">20~μ C </tex-math> /cm <tex-math notation="LaTeX">^2) </tex-math> .