Is the power-law model applicable beyond the direct tunneling regime?

The validity range of the power-law model, used for evaluation of the voltage acceleration of time-dependent dielectric breakdown, is investigated for extendibility. Up to now the model is shown to describe the experimental data in the direct tunneling regime very well, but it is also discussed for the voltage range, where elastic Fowler-Nordheim tunneling dominates. However, in the voltage range from about 3.5 to 8 V physical mechanisms controlling conduction and degradation change significantly. It is demonstrated in this work that this can in fact result in an over- or underestimation of the voltage acceleration behavior especially when the assessment is based on a small voltage range. But on a larger scale the voltage acceleration can be described by a power-law like behavior up to 10 V with a change in the power-law exponent from 30 in the high voltage regime above 5.3 V and 44 below this transition voltage. This threshold corresponds to the change in the defect generation rate already reported in literature.