Physical study of the power diode turn-on process

The power diode turn-on process has been investigated in detail. The study was performed by numerical device simulation (MEDICI), allowing analysis of the inner physics associated with the turn-on effect. In particular, the importance of considering both diffusion and drift current density terms during forward recovery at low injection conditions is shown. It is also shown that the commonly used ambipolar transport equation (ATE) cannot correctly describe this process. Instead, a more general transport equation is proposed which is valid during the turn-on phase, but also at all injection levels, i.e. full cycle of device operation.