Disturbed bonding states in SiO/sub 2/ thin-films and their impact on time-dependent dielectric breakdown

A temperature-independent field acceleration parameter /spl gamma/ and a field-independent activation energy /spl Delta/Ho can result when different types of disturbed bonding states are mixed during time-dependent dielectric breakdown (TDDB) testing of SiO/sub 2/ thin films. While /spl gamma/ for each defect type alone has the expected 1/T dependence and /spl Delta/Ho shows a linear decrease with electric field, a nearly temperature-independent /spl gamma/ and a field-independent /spl Delta/Ho can result when two or more disturbed bonding states are mixed. These observations suggest strongly that the oxygen vacancy is an important intrinsic defect for breakdown and that field, not current, is the cause of TDDB under low-field conditions.