Low Polarization Loss of Long Endurance on Scavenged Ru-Based Electrode Ferroelectric Hf_0.5Zr_0.5O₂ by Optimizing TiN_x Interfacial Capping Layer and Its Fatigue Mechanism

Double remnant polarization (2P _r ) values are increased significantly from 17.1 μC/cm ² to 39.9 μC/cm ² by reducing the TiN _x interfacial capping layer (ICL) thickness from 3 nm to 1 nm in the Ru/TiN _x /Hf _0.5 Zr _0.5 O ₂ (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 TiN _x 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 >10 ¹¹ cycles under high ±4 MV/cm, 0.5 μs (remaining higher 2P _r value of >20 μC/cm ² ).