The non-uniqueness of breakdown distributions in silicon oxides

Time-dependent-dielectric-breakdown (TDDB) distributions obtained from oxides of the same physical geometry and stressed at the same electric field were found to shift to shorter times when the amount of energy available to flow through electric breakdowns was increased. This paper shows that TDDB distributions are nonunique and that for a breakdown model to accurately describe the reliability of an oxide during actual use conditions, the oxide thermal geometry must be taken into account. An accurate method of obtaining electric breakdown distributions is also presented which allows the use of smaller sample sizes to obtain time-dependent-electric-breakdown (TDEB) distributions which are similar to TDDB distributions.