Configurable ultra-low operating voltage resistive switching between bipolar and threshold behaviors for Ag/TaO_x/Pt structures

An ultra-low operating voltage bipolar resistive switching is observed in Ag/TaO_x/Pt devices. They show a typical bipolar resistive switching with both low operating voltages and high cycling endurance when the compliance current (I_CC) is 0.3 mA. Moreover, the operating voltage is considerably influenced by the grain size of the film. The V_Forming increases dramatically when the grain size exceeds a critical value. Meanwhile, the bipolar resistive switching and threshold switching in Ag/TaO_x/Pt devices can be converted to each other by changing the magnitude of the I_CC. Finally, a model based on the migration of Ag⁺ is proposed to explain the ultra-low operating voltage and the critical effect of grain size. The model is proved by simulation. These findings may lead to ultra-low power memories and contribute to a further understanding of the resistive switching effect.