Microscopic Analysis of Degradation and Breakdown Kinetics in HfO₂ Gate Dielectric after Ions Irradiation

We combine experiments and simulations to investigate the degradation dynamics and dielectric breakdown (BD) of SiO_<i>x</i>/HfO₂ gate stacks irradiated with varying doses of 40 MeV carbon ions. The analysis of postirradiation electrical characteristics (current-voltage, <i>I</i>-<i>V</i>, capacitance-voltage, <i>C</i>-<i>V</i>, and conductance-voltage, <i>G</i>-<i>V</i>) reveals that the HfO₂ layer is the most affected by irradiation-induced damage, leading to the formation of defects consistent with oxygen vacancies. Postirradiation constant voltage stress (CVS) experiments reveal an inverse dependence of time to breakdown (<i>t</i>_BD) and Weibull slopes (β) on the irradiation dose. These trends are accurately reproduced by statistical physics-based breakdown simulations only when accounting for partial percolation paths induced by ion strikes during irradiation, as well as a spatially correlated defect generation process during subsequent electrical stress. Our findings are crucial for designing radiation-hardened materials and improving the resilience of electronics operating in harsh environments.