Electrochemical processes and device improvement in conductive bridge RAM cells

In this paper, we discuss the recent progress on the fundamental understandings of ECM/CBRAM cells but also on the improved device structures and reliability for high‐density applications. The influences of the local chemical environment and the material selection/combination are highlighted, and the filament dynamics is described in a general framework that relates all the reported switching modes. Furthermore we also detail some correlation evidences between the filament shape and device electrical characteristics. Finally, we discuss technological challenges related to current‐scaling and cell size‐scaling. Large switching variability associated to low current needs to be mitigated by appropriate Write‐verify methods, while cell scaling requires novel processing techniques such as Cu dry‐etch. The aim of this Review on ECM/CBRAM cells is to address the broad range from the up‐to‐date understanding of the switching mechanisms at the nanoscopic scale to the development of advanced and scaled device structures showing progress in memory properties and reliability for high‐density applications.