New fundamental defects in a-SiO/sub 2/

The atomic structure and spin properties of two previously undescribed amorphous silicon dioxide fundamental point defects have been characterized for the first time by ab initio quantum mechanical calculations. Both defects are electrically neutral trivalent silicon centers in the oxide. One of the defects, the X-center, is determined to have an O/sub 2/Si/spl equiv/Si/sup /spl dagger// atomic structure. The other defect, called the Y-center, is found to have an OSi/sub 2//spl equiv/Si/sup /spl dagger// structure. Calculated electronic and electrical properties of the new defect centers are consistent with the published characteristics of the oxide switching trap or border trap precursors.