A New TDDB Reliability Prediction Methodology Accounting for Multiple SBD and Wear Out

In this paper, we study time-dependent dielectric breakdown in thin gate oxides and propose a new methodology applicable to a wide range of gate stacks for extracting soft breakdown (SBD) and post-SBD wear-out (WO) parameters from measuring the time to hard breakdown (t(HBD)) only. By introducing this methodology, we can get around the problems related to the detection of the first SBD and the corresponding WO time. We show that the shape of the HBD distribution can change with voltage and area, depending on the ratio of WO and SBD times. We also explain why, in literature, contradictory results related to the voltage acceleration factors of SBD and WO are reported. Finally, we construct a complete reliability prediction model that includes SBD and WO.