Observation of Self-Reset During Forming of the TiN/HfOx/TiN Resistive Switching Device

Study on complementary resistive switching of TiN/HfO
_x
/TiN memory device has shown that the device is highly susceptible to self-reset, i.e., the device is automatically programmed into the high-resistance state during forming. This is observed in the following opposite-polarity voltage sweep, in which the device exhibits a set behavior (instead of a reset as typically observed in bipolar switching mode). Interestingly, the self-reset behavior is: 1) suppressed in devices with a thin Al
₂
O
₃
layer inserted in-between the TiN and HfO
_x
and 2) completely eliminated in devices with the TiN cathode replaced by Pt. These results are consistent with a hypothesis that ascribes the self-reset to the migration of oxygen ions from the cathode interfacial oxide into the conducting filament in the HfO
_x
during the forming transient, thus resulting in the disruption of the filament. With the reduction in voltage loading across the cathode interfacial oxide during forming transient in devices with the Al
₂
O
₃
interlayer and the elimination of interfacial oxide in devices with the Pt cathode, the occurrence of self-reset is reduced or eradicated.