Solution-Processed Complementary Resistive Switching Arrays for Associative Memory

Abstract

Complementary resistive switches (CRS) based on back-to-back nanofilamentary resistive RAM devices have been fabricated by an all-solution-processed method, employing inkjet-printed Ag and Au contacts and a spin-coated sol–gel zirconium oxide dielectric layer. The devices demonstrate electrical switching behavior below 3 V, stable on-state windows, reasonable cycle lifetimes, and can be implemented in $2\times 2$ memory arrays with no crosstalk during addressing. For reliable operation and high yields of the CRS devices, printing and annealing processes were carefully optimized to eliminate the coffeering effect on the bottom electrode, and produce a pin-hole free dielectric. The arrays are fully pulse programmable and are able to retain their state for > $10^{4}$ s. Additionally, the arrays can be operated as associative or content addressable, memory for pattern matching applications, which is demonstrated through a basic hamming distance mapping measurement for different stored data states.