Charge Pumping as a Monitor of off-State TDDB in Asymmetrically Stressed Transistors

Two parameters - the distribution of failure times and the voltage dependence of defect generation - define IC lifetime limited by time-dependent dielectric breakdown (TDDB). While the physics of both parameters for uniformly stressed thin-gate dielectric are well known, we find that the corresponding parameters for asymmetric off-state TDDB are anomalous and cannot be understood by a simple application of the classical models. Here we report experimental and theoretical resolutions of the anomaly and show that, despite the complexity of the breakdown process, a simple charge-pumping measurement provides an unambiguous/effective/inexpensive monitor of the anomalous Weibull slopes and nontraditional voltage-acceleration factors for off-state TDDB.