Reliable Assessment of Progressive Breakdown in Ultrathin MOS Gate Oxides Toward Accurate TDDB Evaluation

Progressive breakdown (PBD), which is now considered a key feature in the breakdown of ultrathin gate oxides, was investigated to help develop a reliable time-dependent-dielectric-breakdown qualification. In particular, this paper focused on treating multiple competing breakdown phenomena (multiple-BD). By using metal-oxide-semiconductor transistors with extremely small gate areas, the effect of the multiple-BD was clearly revealed. Through PBD assessments that excluded the multiple-BD effect and also the influence of measurement time-step limitations, a reliable hard-breakdown lifetime qualification process was demonstrated.