A new on-line method to evaluate the NBTI degradation of the ultrathin oxide

A new gate current (GC) on-line method is presented to evaluate the degradation of negative bias temperature instability (NBTI) in the ultrathin oxide. The total density of traps and corresponding threshold voltage shifts were measured by on-line monitoring the gate tunneling current. Comparison between GC method and conventional methods indicates the former is more efficient to avoid the recovery influence upon the NBTI degradation. It is found that two kinds of traps coexist during the NBTI degradation. And the saturation tendency of threshold voltage shifts was not found during NBTI degradation