Dielectric breakdown mechanism of thin-SiO/sub 2/ studied by the post-breakdown resistance statistics

Abstract

The dielectric breakdown mechanism of SiO/sub 2/ has been discussed on the basis of the experimental results of the post-breakdown resistance (R/sub bd/) distribution. We have noticed for the first time that R/sub bd/ of SiO/sub 2/ in MOS devices is strongly related to the SiO/sub 2/ breakdown characteristics such as the polarity dependence or the oxide field dependence of Q/sub bd/. In this paper, we discuss the dielectric breakdown mechanism of SiO/sub 2/ from the viewpoint of the statistical correlation between the R/sub bd/ distribution, the Q/sub bd/. distribution, and the emission energy just at the SiO/sub 2/ breakdown, by changing the stress polarity, stress field, and the oxide thickness. For complete dielectric breakdown, it has been clarified that the R/sub 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/sub bd/ can be uniquely expressed by the energy dissipation at the occurrence of dielectric breakdown of SiO/sub 2/ for the complete breakdown. Furthermore, it has been clarified that R/sub bd/ does not depend on the energy dissipation at the occurrence of quasidielectric breakdown.