Critical gate voltage and digital breakdown: Extending post-breakdown reliability margin in ultrathin gate dielectric with thickness ≪ 1.6 nm

The saturation of a critical gate voltage at 2-2.4 V for SiON with thickness < 1.6 nm (EOT < 1.4 nm) extends the role of digital breakdown (BD) in prolonging progressive BD at nominal voltages. As a result, the post-BD gate leakage degradation rate, which is extrapolated from a high voltage using the conventional approach, is highly overestimated, warranting one to revise the post-BD reliability assessment.