SIMULATION OF TRANSIENT SELF-HEATING DURING POWER VDMOS TRANSISTOR TURN-OFF

The transient thermal behaviour, based on a rigorous transient thermod ynamic treatment, of a power VDMOS transistor during turn-off is prese nted. The time variation of the interior lattice temperature within th e device is calculated by self-consistently solving the fully coupled Poisson's equation and transient electron continuity equation together with the transient heat flow equation. The simulation takes account o f temperature dependent heat conduction and capacity and includes ther moelectric currents due to temperature gradient. To make the transient thermal simulation more robust, a new analytical expression for heat capacity is used.