Demonstration of Large MW and Prominent Endurance in a Hf_0.5Zr_0.5O₂ FeFET With IGZO Channel Utilizing Postdeposition Annealing

Abstract

With high potential for back-end-of-line (BEOL) integration, HfO2-based FeFETs with amorphous oxide semiconductor (AOS) channels have shown impressive application prospects in recent years, but the issue of limited endurance is still unsolved, which can be mainly attributed to the poor thermal stability of AOSs and the compromised manufacturing process. In this work, we propose a postdeposition annealing (PDA) process to crystallize the 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<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>O2 (HZO) layer. Compared with that of the FeFET obtained via the conventional post-metal annealing (PMA) method, the endurance of the optimized FeFET is significantly improved owing to the better HZO-AOS interface. With a TCAD simulation, we prove that the lower the dielectric constant of the HZO layer is, the greater the memory window (MW) that can be achieved, whereas the decreased remnant polarization effect is relatively slight. The proposed FeFET shows a superior large MW (3 V) and excellent endurance, achieving <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{{10}}$ </tex-math></inline-formula> cycles with only slight MW degradation, and a 2-bit/cell data storage ability.