Scaling limits of resistive memories

This paper is intended to provide an expository, physics-based, framework for the estimation of the performance potential and physical scaling limits of resistive memory. The approach taken seeks to provide physical insights into those parameters and physical effects that define device performance and scaling properties. The mechanisms of resistive switching are based on atomic rearrangements in a material. The three model cases are: (1) formation of a continuous conductive path between two electrodes within an insulating matrix, (2) formation of a discontinuous path of conductive atoms between two electrodes within an insulating matrix and (3) rearrangement of charged defects/impurities near the interface between the semiconductor matrix and an electrode, resulting in contact resistance changes. The authors argue that these three model mechanisms or their combinations are representative of the operation of all known resistive memories. The central question addressed in this paper is: what is the smallest volume of matter needed for resistive memory? The two related tasks explored in this paper are: (i) resistance changes due to addition or removal of a few atoms and (ii) stability of a few-atom system.