Dependence of Electrical Properties of Super Junction Diode on Voids within Trench-refill Region

In super junction devices fabricated by trench-refill method, we have to establish a method to reject devices containing void in the trench-refill region, since such voids containing devices have low reliability in long time operation. However, detection of voids are normally done with destructive inspections, such as cross sectional observation. In this paper, we propose to stratify devices by reverse recovery time (trr) as a non-destructive method, because we found a relation between trr and the void existence. Furthermore, we conduct a simulation to understand this relation.