Temperature and stress polarity-dependent dielectric breakdown in thin silicon dioxides has been carefully investigated. The experimental data show that the time to breakdown under a constant-current injection has two kinks around 330 and 230 K for 4- and 10-nm-thick oxides under both stress polarities. It has been found that thinner oxides have a stronger temperature dependence (a larger activation energy) even if the field dependence of the activation energy is taken into consideration, and also that, from the gate voltage shift during the constant-current injection, the postbreakdown characteristics strongly depends on the stress polarity for thinner oxides. ©1998 American Institute of Physics.