Unveiling the Switching Mechanism of a TaOx/HfO2 Self-Selective Cell by Probing the Trap Profiles With RTN Measurements

Self-selectivecells (SSCs) with built-in nonlinearity provide a promising solution for overcoming the leakage current issue of 3-D vertical resistive random access memory arrays. However, deep understanding of the switching mechanism of the SSC device is still lacking, hindering the effective improvement of the device performance. In this letter, we investigated the switching mechanism of the TaO
_x
/HfO
₂
SSC device by probing the trap profiles with RTN measurements. Both the vertical locations and energy levels (X
_T
, E
_T
) of defects in the HRS and LRS could be calculated by the bias-dependence of the capture and emission time constants (τ
_e
and τ
_c
). Using the comparison of the defect profiles before and after the resistive switching, an active region in the TaO
_x
layer adjacent to the HfO
₂
layer could be clearly identified. Based on these results, a clear picture of resistive switching in the TaO
_x
/HfO
₂
SSC was obtained.