Assessment of read disturb immunity in conducting bridge memory devices – A thermodynamic perspective

Abstract

Conducting bridge random access memory (CBRAM) devices operate on the basis of repeated nucleation and rupture of the metallic filament during the SET and RESET transitions. One of the critical reliability metrics for any non-volatile memory (NVM) technology is read disturb immunity, which refers to the ability of the device to keep the filament stable and unperturbed during the reading phase. While read disturb has been analyzed in detail for OxRAM which works based on the principle of oxygen vacancy generation and oxygen ion drift/diffusion, the susceptibility of CBRAM to read disturb events has not been analyzed in-depth. We make use of electrical test data, first order thermal model and fundamental thermodynamics to assess the stability of the CBRAM filament in both the high resistance state (HRS) as well as low resistance state (LRS). Our analysis reveals that the HRS retention is very good, while LRS retention can be quite poor for the Nickel-based CBRAM stack.