Effects of stress on resistive switching property of the NiO RRAM device

• The device displayed a bipolar switching after annealing for 10 min.
• A unipolar switching was observed when the annealed time increased to 1 h.
• Based on the microstructural analysis, the reason was attributed to the stress.
• A physical model was established and well explained the experimental phenomena.

Resistive random access memory (RRAM) devices are considered as one of the most promising candidates for the next generation of high-density non-volatile memories (NVMs). In this work, NiO RRAM devices were fabricated by DC magnetron sputtering. With the changing of the annealing time, different switching properties of RRAM were observed. When the sample annealed for 10 min, the device displayed a bipolar switching. On the other hand, a unipolar character behavior of the device was observed when the annealed time increased to 1 h. Based on the microstructural analysis, the reason was attributed to the stress. When the annealed time is short, a relative large residual stress remained in the device. It increases the diffusion barrier and traps the ion migration, correlated with a bipolar character behavior of the device. On the contrary, the stress was released when the annealed time increased up to 1 h. Then, the device displayed a unipolar switching due to the high diffusion coefficient. This discovery has the potential to reveal the mechanism of switching between unipolar and bipolar of the device and open up new avenues on the research of RRAM.

(a) The film was annealed 10 min and shown bipolar switching. (c and e) The model for bipolar property during SET and RESET process. (b) The bipolar property for the device annealed 1 h and the negative unipolar obtained. (d and f) The model for unipolar property during SET and RESET process.Figure optionsDownload as PowerPoint slide