Necessity of pulse hot carrier evaluation in suppressing self-heating effect for SOI smart power

Hot carrier (HC) reliability of SOI LDMOS suppressing self-heating effect was investigated. We evaluated an appropriate HC degradation by controlling junction temperature (Tj) within the temperature range the circuit is actually operated of. A gate pulse HC evaluation system was used to suppress the self-heating effect during HC stress. Pulse HC stress shows that the drain current shift is three times larger and the threshold voltage shift is 10 times smaller at Tj = 25°C than the shifts evaluated by means of DC stress. We find that pulse stress evaluation is essential when estimating degradations of actual circuit operating temperatures for SOI smart power. The degradation mechanism was also evaluated using a charge pumping measurement.