SRAM stability analysis considering gate oxide SBD, NBTI and HCI

For ultrathin gate oxide, soft breakdown (SBD) has been extensively studied but not fully integrated into circuit reliability simulation. Using a 6T SRAM cell as a generic circuit example, the time-dependent SBD was incorporated into circuit degradation analysis based on the exponential defect current growth model [1]. SRAM cell stability degradation due to individual failure mechanism was characterized. Multiple failure mechanisms degradation effect was also studied in regard of SRAM cell operation. Simulation results showed that gate oxide SBD is the dominating failure mechanism which causes SRAM stability and operation degradation, NBTI and HCI have much less effect.