Truly Electroforming-Free and Low-Energy Memristors with Preconditioned Conductive Tunneling Paths

1S1R (1 selector and 1 memristor) is a laterally scalable and vertically stackable scheme that can lead to the ultimate memristor density for either memory or neural network applications. In such a scheme, the memristor device needs to be truly electroforming-free and operated at both low currents and low voltages in order to be compatible with a two-terminal selector. In this work, a new type of memristor with a preconditioned tunneling conductive path is developed to achieve the required performance characteristics, including truly electroforming-free, low current below 30 mu A (potentially <1 mu A), and simultaneously low voltage approximate to +/- 0.7 V in switching operations. Such memristors are further integrated with two types of recently developed selectors to demonstrate the feasibility of 1S1R integration.