The improved resistive switching of HfO₂:Cu film with multilevel storage

The Cu-doped and undoped HfO₂ films were fabricated by magnetron sputtering. The effect of Cu doping on resistive switching (RS) of HfO₂ film was demonstrated. Improvements in ON/OFF ratio and switching parameters were observed. The multilevel behavior of Cu/HfO₂:Cu/Si sample was also investigated by controlling the current compliance during set process and at least three low resistance states (LRSs) for data storage could be obtained. The three LRSs and the high resistance state can be distinguished in a range of 10³ and the HfO₂:Cu sample exhibited good reliability. The RS behavior of HfO₂:Cu sample can be well interpreted by the proposed filamentary model. The oxygen vacancies and Cu ions in the film are both responsible for the RS behaviors.