Multi-mode resistive switching behaviors induced by modifying Ti interlayer thickness and operation scheme

To overcome the practical issues existed in RRAMs application, complementary resistive switching (CRS) and self-compliance effect are investigated to alleviate sneak current issue and avoid external compliance current (Icomp), respectively. It is remarkable that the two resistive switching (RS) behaviors are attempted to achieve in the same system of Pt/HfO2(7.5−x)/Ti(2x)/HfO2(7.5−x)/Pt (x = 0, 2.5, 3.5 nm) device fabricated by magnetron sputtering, i.e., multi-mode resistive switching behaviors are modulated by varying Ti interlayer thickness and operation scheme, such as initial Icomp and applied voltage during reset switching. As indicated by the results, typical bipolar resistive switching (BRS) and CRS behaviors exhibit in Pt/HfO2(∼4 nm)/Ti(∼7 nm)/HfO2(∼4 nm)/Pt devices, and self-compliance effect appears in Pt/HfO2(∼5 nm)/Ti(∼5 nm)/HfO2(∼5 nm)/Pt devices. After investigated the conductive mechanisms, it is proposed adopting conceivable switching mechanism associated with the formation of oxygen vacancy (VO) and metallic conduction filament (CF) to understand CRS and self-compliance effect. The exploration of multi-mode RS behaviors paves the way to improve the flexibility and convenience of RRAMs in actual application.