Impact of oxygen concentration at the HfOx/Ti interface on the behavior of HfOx filamentary memristors

Abstract

Moving toward the future computing and non-volatile memory, memristors have gained wide attention for their in-memory computing and neuromorphic computing applications. The resistive switching dynamics in oxide-based memristors rely critically on oxygen ions and their recombination with oxygen vacancies to partially rupture and form the conductive filament (CF) for modulating the device between the low resistance state and high resistance state. In this study, we investigated the effect of oxygen ion concentration at the HfOx/Ti interface on the behavior of HfOx-based filamentary memristors. Devices with higher oxygen ion concentrations at the HfOx surface were fabricated by treating with oxygen plasma at various times on the as grown ~ 5 nm HfOx active layer via atomic layer deposition. Detailed X-ray photoelectron spectroscopy and depth profile analyses verify the excess oxygen ion presence at the HfOx surface, and the formation of a thin TiOx layer between the HfOx and Ti layers, resulting in a HfOx/TiOx/Ti interface structure. This work demonstrates the importance of interface chemistry at the HfOx/Ti interface region and its oxygen ion motion for controlled growth of the CF during memristor set operation, which is favorable for analog logic computation.