The effects of substrate temperature on ZnO-based resistive random access memory devices

Ag/ZnO/Zn/Pt structure resistive switching devices are prepared by radio frequency magnetron sputtering. The ZnO thin films are grown at room temperature and 400 ℃ substrate temperature, respectively. By comparing the data, we find that the latter device displayed better stability in the repetitive switching cycle test, and the resistance ratio between a high resistance state and a low resistance state is correspondingly increased. After 10⁴-s storage time measurement, this device exhibits a good retention property. Moreover, the operation voltages are very low: -0.3 V/-0.7 V (OFF state) and 0.3 V (ON state). A high-voltage forming process in the initial state is not required, and a multistep reset process is demonstrated.