The degradation of N-type symmetrical lateral double diffused MOS with different gate voltage stress condition

In this paper, a comprehensive study of different level hot carrier stress conditions for N-type symmetrical lateral double diffused MOS (ns-LDMOS) is carried out. It is noted that there are two peaks bulk current observed for different gate voltage due to Kirk effect happening. The experimental results show two turn-over of Idsat degradation with low Vgs (mainly caused by impact ionization current increase), and one turn-over of Idsat degradation with median Vgs, which is caused by interface states generation. For high Vgs condition, significant damage is occurred on ns-LDMOS. A series of EFA and PFA demonstrate that this damage is not caused by hot carrier injection, but the self-heating effect in body of ns-LDMOS.