Modeling and Optimization of Bilayered TaOx RRAM Based on Defect Evolution and Phase Transition Effects

A comprehensive physical model on the resistive switching (RS) behaviors of bilayered TaO
_x
-based RS access memory [resistive random access memory (RRAM)] is presented. In the model, the effects of the generation and recombination (G-R) of oxygen vacancies (
$V_{{\rm{O}}}$
), phase transition (P-T) between Ta
₂
O
₅
and TaO
₂
, and the interaction (I-A) between Ta
₂
O
₅
and TaO
_x
layers are involved to explain the RS behaviors based on
ab initio
calculations. An atomistic Monte Carlo simulation method based on the model is developed to investigate the dynamic physical processes and reproduce the experimental phenomena. The impacts of G-R and P-T as well as the I-A effects on the RS behaviors of a bilayered Ta
₂
O
₅
/TaO
_x
structure and the device performances are identified. This paper indicates that the G-R effect dominates the RS behaviors, and self-compliance is due to the I-A effect. Based on the simulations, the optimization guidance of a bilayered TaO
_x
-based RRAM is presented.