Low-Temperature Characteristics of HfOx-Based Resistive Random Access Memory

This letter investigates the low-temperature switching characteristics and conduction mechanism of the Pt/HfO_x/TiN resistive random access memory devices. For the first time, Pt/HfO_x/TiN devices were demonstrated to be well functional at ultralow temperature (4 K). The switching voltages slightly increase at lower temperature. The failure state in a breakdown sample shows a metallic behavior, while the normal low-resistance states and high-resistance states show a semiconducting behavior. The slope change in the 1/kT plot below 77 K indicates a transition from the nearest-neighboring hopping to the variable range hopping. Different slopes or activation energies are observed at the same resistance level in the same device but after different programming cycles, indicating a cycle-dependent variation of the filament configuration.