Spatio-Temporal Defect Generation Process in Irradiated HfO2 MOS Stacks: Correlated Versus Uncorrelated Mechanisms

In this paper, we analyze the dependence of the Weibull slope (ß) extracted from TDDB tests on HfO
₂
MOS capacitors (MOSCAPs) on the initial density of defects artificially induced by carefully tuned micro beam irradiation experiments with different carbon dosages. The consistent experimental trend of reducing p with increasing defect density was reproducible only with physics-based breakdown simulations that considered correlated defect generation in HfO
₂
and localized damage (partial percolation paths) traces created by the impinging ions. Scenarios of spatially random initial defect distribution and random stress-induced defect generation (in space and time) could not explain the experimental trends, confirming that correlated defect generation does exist in HfO
₂
thereby altering the conventional understanding of TDDB by quite a bit.