Description:
Electrical properties of thin silicon dioxide films have been investigated for samples that suffered from the Fowler–Nordheim (F–N) stress and subsequent annealing. The time-dependent dielectric breakdown (TDDB) lifetime for samples after annealing >400 °C was found to be longer than that without anneal; about 60% of the amount of damage responsible for the lifetime was annealed out at a temperature of typically 800 °C for 30 min. On the other hand, capacitance–voltage (C–V) measurements indicated that trapped charges were almost annealed out even at a temperature of 300 °C for 30 min. Moreover, the reinjection of F–N current showed that the trapping sites of holes and electrons which are electrically neutral remained after the annealing of trapped charges at temperatures >300 °C. It follows that the recovery of TDDB lifetime presently observed through annealing at temperatures >400 °C was caused by the anneal of neutral trapping sites created by F–N stresses.