The dielectric breakdown mechanism of SiO2 has been discussed on the basis of the experimental results of the post-breakdown resistance (R-bd) distribution, me have noticed for the first time that Rbd Of SiO2 in MOS devices is strongly related to the SiO2 breakdown characteristics such as the polarity dependence or the oxide field dependence of Q(bd) In this paper, we discuss the dielectric breakdown mechanism of SiO2 from the viewpoint of the statistical correlation between the Rbd distribution, the Q(bd) distribution, and the emission energy just at the SiO2 breakdown, by changing the stress polarity, stress field, and the oxide thickness. For complete dielectric breakdown, it has been clarified that the R-bd distribution under the substrate electron injection is clearly different from that under the gate electron injection. We have also found that, irrespective of the stress current density, the gate oxide thickness and the stressing polarity, R-bd can be uniquely expressed by the energy dissipation at the occurrence of dielectric breakdown of SiO2 for the complete breakdown. Furthermore, it has been clarified that R-bd does not depend on the energy dissipation at the occurrence of quasidielectric breakdown.