Electromigration-induced resistance switching in indented Al microstrips

Non-volatile resistive memory cells are promising candidates to tremendously impact the further
development of Boolean and neuromorphic computing. In particular, nanoscale memory-bit cells
based on electromigration (EM)-induced resistive switching in monolithic metallic structures have
been identified as an appealing and competitive alternative to achieve ultrahigh density while keeping
straightforward manufacturing processes. In this work, we investigate the EM-induced resistance
switching in indented Al microstrips. In order to guarantee a large switching endurance, we limited
the on-to-off ratio to a minimum readable value. Two switching protocols were tested, (i) a variable
current pulse amplitude adjusted to ensure a precise change of resistance, and (ii) a fixed current pulse
amplitude. Both approaches exhibit an initial training period where the mean value of the device’s
resistance drifts in time, followed by a more stable behavior. Electron microscopy imaging of the
devices show irreversible changes of the material properties from the early stages of the switching
process. High and low resistance states show retention times of days and endurances of∼10^3 cycles.