Memory effect of RF sputtered ZrO2 thin films

Electrical properties of RF sputtered ZrO2 memory thin films were investigated in this study. The device with structure Al/ZrO2/Pt shows a reproducible resistive switching behavior traced over 100 times at room temperature. Moreover, by using various top electrodes, such as Pt, Cu, Ni, Ag, Ti, and even W-probe, the resistive switching phenomenon can be observed in ZrO2-based memory with Pt bottom electrode, indicating that the ZrO2 bulk dominates the resistive switching. The bias polarity dependent resistive switching behavior is demonstrated in the Ti/ZrO2/Pt device, which might be due to interface reaction between Ti and ZrO2 film. The resistance value of high conductive state in the Ti/ZrO2/Pt device decreases with increasing current compliance implying the possibility for multi-bit storage. Besides, the Ti/ZrO2/Pt device can be operated over 2000 resistive switching cycles at 85 °C by sweeping DC voltage, and the two memory states demonstrate good stability under read voltage stress at room temperature and 85 °C. The write-read-erase-read operations can be over 103 cycles at 85 °C. No data loss is found upon successive readout before and after performing 103 endurance cycles at 85 °C. According to above experimental results, the ZrO2 thin film has high potential for nonvolatile memory application.