Electrode-engineering on HfO2-based RRAM for variability control and hardware security

The intrinsic cycle-to-cycle variability in resistive random access memory (RRAM) devices supports their suitability as seed sources in circuits requiring stochastic input. This article presents the fabrication, characterization, and analysis of FTO/HfO2/Ag, FTO/HfO2/Cu, and co-sputtering (CS) FTO/HfO2-SiO2/Ag RRAMs for hardware security and stochastic applications. The RRAM switching-layer thin film has been deposited by radio frequency (RF) sputtering, and silver (Ag) and copper (Cu) electrodes were used to tune the switching behavior. Statistical analysis of cycle-to-cycle variability shows a coefficient of variation (CV) of ∼0.32 for FTO/HfO2/Ag and ∼0.088 for FTO/HfO2/Cu devices. It supports the possible suitability of the Ag-based devices for high-variability applications and the ability to control RRAM variability through fabrication choices. These controllable characteristics suggest proposed nanofabricated devices as possible candidates for applications in hardware security primitives, secure memory elements in low-power hardware, and Internet of Things (IoT) platforms. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2026.