Investigation of multiple soft breakdown during time-dependent dielectric breakdown

In this paper, we studied the multiple soft breakdown phenomena of gate oxide during TDDB (Time Dependent Dielectric Breakdown). After the soft breakdown, the parameters of the device had been greatly degraded (as a result, the device lost its original functions), although the multiple soft breakdown did not lead the oxide catastrophical failure. Further analysis also verified that the gate oxide had been damaged after the first soft breakdown. We found that there is a very good match between the times of soft breakdown and the failure points fixed using EMMI-OBIRCH system. Moreover, such correspondence was verified using the in-situ failure analysis method. Finally, we proposed an explanation concerning the oxide breakdown based on the phenomenon.