Dynamic Modeling of Dual Speed Ferroelectric and Charge Hybrid Memory

This paper presents a physical model for program and retention transients in ferroelectric (FE) and charge hybrid nonvolatile memory. A region-by-region statistical model for domain switching in polycrystalline FEs was incorporated with the tunneling current simulations to predict the memory window (AV_TH) evolution during program and retention operations. The simulations validated the two-step program mechanism experimentally observed in such memories: rapid initial domain switching on account of high fields in the FE layer followed by field enhancement in the tunneling dielectric which initiates electron injection into the storage nodes. Further, these simulations were shown to accurately account for individual ΔV_TH from the two additive memory mechanisms at all program times. The depolarization effect was shown to be dominant for ΔV_TH loss at short and moderate retention time scales (<;100 s). This model was further used to provide realistic estimates in achieving dual speed program and the corresponding dual mode retention characteristics akin to a DRAM and flash hybrid operation.