Statistical SBD modeling and characterization and its impact on SRAM cells

In this paper, we present a physics-based SPICE model for statistical soft breakdown (SBD) in ultrathin oxide. Statistical SBD induces an increase in gate leakage current (I_G-BD) based on the time to breakdown (t _BD) and the location of the percolation path in the channel. The proposed model has been validated with experimental data, and fed into circuit simulators to predict the degradation of device/circuit performance. Using the model, we analyzed the impact of the increased I_G-BD due to the first SBD on cell stability and performance in SRAM cells. We observed that I _G-BD variation due to SBD increases READ and WRITE failure probability, resulting in reduced lifetime.