Decoupling Thermal Kinetics and Structural Evolution in HfO2 RRAM via Broadband Impedance Spectroscopy: A SPICE Model for Analog Applications
Year: 2026
Type: preprint
Abstract: The integration of HfO2-based resistive random-access memory (RRAM) into analog circuits and neuromorphic hardware requires accurate, physics-based small-signal models. In this work, we employ broadband impedance spectroscopy to physically isolate the distinct structural and kinetic components governing the alternating current (AC) response of TiN/Ti/HfO2/W memristive devices, thereby providing such a model. Measurements were performed over a wide temperature range (77 K to 350 K), across multiple device areas, and at various resistance states controlled by compliance current. The AC response reveals distinct relaxation processes, which are accurately described by an electrical equivalent circuit that isolates the individual electrical signatures of the filament constriction, the interfacial boundary, and the bulk conductive path. The low-frequency relaxation, attributed to the filament constriction, exhibits a strong exponential temperature dependence, allowing for the extraction of the thermal activation energy associated with trap-assisted charge transport within the oxygen vacancy-rich gap. In contrast, the bulk-related response is temperature-independent but strongly depends on the resistive state. The model is further validated by the scaling of the high‑frequency pole with device area, confirming its geometric origin. As a result, our model decouples the thermal kinetics from the structural evolution of conductive filaments in emerging non-volatile memories. Finally, to demonstrate the practical utility of this model, it is implemented in LTSpice to design all-memristive analog filters and a neuromorphic signal mixer. This approach takes advantage of the properties of both pristine and programmed devices to eliminate the need for conventional passive components.
Source: ChemRxiv
Institution: Universidad de Valladolid
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
Funder: Agencia Estatal de Investigación
OpenAlex ID: W7220740446