Bipolar Resistive Switching Characteristics of TiN/HfO_x/ITO Devices for Resistive Random Access Memory Applications

Resistive switching characteristics of hafnium oxide are studied for possible nonvolatile memory device applications. The HfO_x films with different oxygen contents are deposited by rf magnetron sputtering under different O₂ flow rates. The films are amorphous, and the stoichiometric of the film is improved by increasing the O₂ flow rate. Current-voltage characteristics of the TiN/HfO_x/ITO device are investigated with 1 mA compliance. The bipolar resistive switching behavior is observed for the TiN/HfO_x/ITO structure, and the resistive switching mechanism of the TiN/HfO_x/ITO structure is explained by trap-controlled space charge limit current conduction.