Modeling of uniform switching RRAM devices and impact of critical defects

Abstract

Uniform switching in RRAM devices has been modeled as field driven transition of multiple defects in the dielectric switching layer. In this analytic model, conductance through the stack is calculated using a resistive network. The effect of neighboring defects in the computation of the effective electric field is accounted for by constructing the potential function and taking its gradient. The model captures the gradual switching and the on- and off- state correlation during cycling. Furthermore, scaling the devices limits the number of active defects resulting in local effects due to favorably positioned critical defects. Abrupt drifts in the memory window can be understood as a consequence of movement of these critical defects. All simulations have been corroborated by a TiN/a-Si/TiO2/TiN based stack.