Method to Evaluate Off-State Breakdown in Scaled Tri-gate Technologies.

The source-drain punch-through current in off-state TDDB stress (OSS) is shown to significantly affect off-state breakdown behavior. This paper introduces a modified methodology for conducting OSS in scaled tri-gate devices at accelerated conditions that avoids artifacts associated with punch-through while enabling reliability risk assessment. The methodology is validated for both NMOS & PMOS devices and provides consistent degradation mechanism. Finally, it is shown that on-state gate-oxide TDDB remains the reliability limiter compared to OSS TDDB.