Investigation of Switching-Induced Local Defects in Oxide-Based CBRAM Using Expanded Analytical Model of TDDB

The degradation behavior of Ag/SiO2-based conductive bridging RAM (CBRAM) is analyzed by conventional and expanded time-dependent dielectric breakdown (TDDB) models. By comparing the total cycling stress with time-to-breakdown (t(bd)) of the SiO2 used as a solid-electrolyte switching layer, it is clarified that the cycling stress does not reach the level at which dielectric breakdown of the SiO2 is triggered. On the other hand, we found that the tbd distribution after several cycles of set/reset stress agrees well with the simulated t(bd) distribution derived from expanded TDDB models, in which we assumed that a large amount of defects exists locally in the device area. This approach is useful for understanding the degradation in solid-electrolyte oxide of CBRAM.