Interfacial Reaction Engineering for Use in Hf0.5Zr0.5O2-Based Metal-Ferroelectric-Metal Capacitors Using N2 + H2 Gas Pretreatment

Abstract

The scaling limitations in traditional semiconductor technologies have accelerated the demand for advanced nonvolatile memory devices. Ferroelectric HfO₂-based thin films, particularly Zr-doped HfO₂ (HZO), have gained prominence due to their ability to support ferroelectricity at reduced dimensions, offering a path toward high-density and low-power memory solutions. However, reliability issues such as wake-up and imprint phenomena still hinder the commercialization of HZO-based devices. In this study, we propose a N₂/H₂ pretreatment for Mo electrodes in metal-ferroelectric-metal (MFM) capacitors to enhance device performance and mitigate interfacial degradation. The pretreatment reduces the MoO_x interfacial layer, lowers the oxidation state, and minimizes work function differences between electrodes, thus improving ferroelectric properties. XPS analysis shows a 10% reduction in Mo⁶⁺, while GAXRD results reveal enhanced stabilization of the ferroelectric orthorhombic phase. Electrical characterization demonstrates increased remanent polarization and a reduced imprint field, with negligible wake-up effects up to 10⁶ cycles. These findings highlight the effectiveness of N₂/H₂ pretreatment in improving the reliability of HZO-based MFM capacitors and promoting their potential for next-generation memory applications.