Low Polarization Loss of Long Endurance on Scavenged Ru-Based Electrode Ferroelectric Hf<sub>0.5</sub>Zr<sub>0.5</sub>O<sub>2</sub> by Optimizing TiN<sub> <i>x</i> </sub> Interfacial Capping Layer and Its Fatigue Mechanism
Asim Senapati, Zhao‐Feng Lou, Jia-Yang Lee, Yi-Pin Chen, Shih‐Yin Huang, S. Maikap, M. H. Lee, C. W. Liu
Abstract
Double remnant polarization (2P <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\text {r}}{)}$ </tex-math></inline-formula> values are increased significantly from <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$17.1~\mu \text{C}$ </tex-math></inline-formula> /cm2 to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$39.9~\mu \text{C}$ </tex-math></inline-formula> /cm2 by reducing the TiNx interfacial capping layer (ICL) thickness from 3 nm to 1 nm in the Ru/TiNx/Hf <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{{0}.{5}}$ </tex-math></inline-formula> 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 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{{11}}$ </tex-math></inline-formula> cycles under high ±4 MV/cm, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.5~\mu \text{s}$ </tex-math></inline-formula> (remaining higher 2Pr value of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$20~\mu \text{C}$ </tex-math></inline-formula> /cm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{{2}}{)}$ </tex-math></inline-formula> .