Plasma-modulated hafnium zirconium oxide nanolaminate capacitors with enhanced ferroelectric polarization and reliability

This study presents a plasma-modulated nanolaminate strategy that simultaneously enhances the polarization response and reliability of Hf 0.5 Zr 0.5 O 2 (HZO) ferroelectric capacitors by controlling the plasma-processing sequence during thin-film deposition without compositional modulation. Based on identical 10-nm-thick HZO films, reference capacitors fabricated using single-process direct-plasma atomic layer deposition (DPALD) and co-PALD (CPALD), denoted as DP and CP devices, respectively, were compared with nanolaminate capacitors fabricated by periodically alternating DPALD and CPALD. A ten-sublayer nanolaminate capacitor (SL10), consisting of five CPALD (1 nm)/DPALD (1 nm) sublayer pairs, exhibited the highest 2P r (twice the remanent polarization) of 37.4 μC/cm 2 after wake-up cycling and a switchable polarization of 34.2 μC/cm 2 based on positive-up–negative-down (PUND) measurements. X-ray diffraction peak deconvolution analysis revealed that the SL10 device exhibited the highest orthorhombic-phase fraction of 64.5%. with a predominant (111) orientation, whereas X-ray photoelectron spectroscopy analysis confirmed the highest stoichiometric Hf chemical-state contribution of 69.5%. Furthermore, the SL10 device maintained stable switchable polarization for up to 4.64 × 10 7 cycles at room temperature and up to 10 7 cycles at an elevated temperature of 85 °C. These results demonstrate that short-period DPALD/CPALD process modulation effectively controls the crystallization behavior of HZO thin films and improves both the ferroelectric performance and fatigue endurance of HZO ferroelectric capacitors.