Cation-based resistance change memory

A potential replacement for current charge-based memory technologies in the nanoscale device regime is a form of resistance change memory (RRAM) which utilizes cation transport and redox reactions to form and remove a conducting filament in a metal-electrolyte/insulator-metal (MEM/MIM) structure. A variety of oxide and higher chalcogenide materials have been used as the silver or copper ion transport medium, yielding devices with similar switching characteristics. The technology has been the subject of extensive research in academia and industry and is in an advanced stage of commercialization but there remain a number of fundamental questions regarding the fine details of device operation and the connection with electrochemical theory at the nanoscale. This review surveys some of the published research in the area and considers the topics of ion-conducting materials, rate limiting steps during device operation and filament stability. Device performance and modelling are also presented and discussed.