Impact ionization, degradation, and breakdown in SiO₂

Destructive breakdown in silicon dioxide is shown to be strongly correlated to the oxide degradation caused by hot-electron-induced defect production and charge trapping near the interfaces of the films. Two well defined transitions in the charge-to-breakdown data as a function of field and oxide thickness are shown to coincide with the onset of mechanisms due to trap creation and impact ionization by electrons with energies exceeding 2 and 9 eV (the SiO2 bandgap energy), respectively. The temperature dependence of charge-to-breakdown is also shown to be consistent with that of these two defect-producing mechanisms.