Intrinsic dielectric breakdown of ultra-thin gate oxides

We have investigated the dynamics of intrinsic dielectric breakdown (BID) in SiO2 thin films of thickness in the range from 35 to 3 nm. BID is obtained under constant voltage Fowler-Nordheim stress at fields between 10 and 12.5 MV/cm. As a function of oxide thickness we have followed with high time resolution the dynamics of the BD transient and analysed the post-BD damage by using transmission electron microscopy, photon emission microscopy and measurements of the post-BD current-voltage (I-V) characteristics. Moreover, the effect of the density of electrons at the cathode on the resulting BD damage is put in evidence. The data are interpreted and discussed in the framework of a model.