Bottom electrode reactivity and bonding strength effect on resistive switching in HfO2-based RRAM

Abstract

This study examined the electrode surface reactivity to investigate the influence of metal types on the switching operation of HfO2-based resistive random-access memory (RRAM) devices. The devices were fabricated by three different bottom electrode (BE) materials: indium tin oxide (ITO), heavily doped silicon (P+-Si), silver (Ag), and their electrical performance was analyzed experimentally. Specifically, an operational mechanism for RRAM is proposed that is based on the differences in SET voltage (VSET) and resistivity ratio (RHRS/RLRS) between ITO and P+-Si BE samples, which have similar work functions. The VSET of ITO BE and P+-Si BE samples were measured at (0.93 and 1.74) V, respectively, with RHRS/RLRS values of (17.6 and 5.33), clearly indicating performance differences between the electrodes. Additionally, the ITO BE sample exhibited more pronounced variability and endurance characteristic degradation compared to the P+-Si. These findings demonstrate a significant difference in operational stability between the two materials. The results suggest that electrode material reactivity and bonding strength impact the ease of conducting filament formation and operational stability at the electrode surface. This study highlights the influence of electrode-specific properties on RRAM performance and commercial viability, underscoring the importance of future RRAM development of electrode material selection. © 2025