Duality characteristics of bipolar and unipolar resistive switching in a Pt/SrZrO3/TiOx/Pt stack

The mechanism of irreversible resistive switching (RS) conversion from bipolar to unipolar operation is investigated in a capacitor structure, SrZrO3/TiOx/Pt, prepared on a Pt/Ti/SiO2/Si substrate. Bipolar RS memory current–voltage characteristics are observed in the RS voltage window from +2.5 V to −1.9 V, which shows excellent durability and retention characteristics. As the voltage bias is increased to greater than +4 V, an additional forming process occurs, irreversibly converting the RS mode from the bipolar to the unipolar mode. In this study, two materials are combined with different switching mechanisms to enable the fabrication of RS memory with desirable characteristics in different current regions.