3.6. Optimum SiC Asymmetric IGBT Structure
An abrupt increase in the collector voltage is observed for the SiC IGBT structure described in the previous section due to punch-through of the space-charge region. This behavior is undesirable in applications for IGBTs. It is possible to avoid this problem by re-engineering the drift region thickness and doping to obtain the needed forward blocking capability while allowing the space-charge region to punch-through to the buffer layer when the collector voltage reaches the supply voltage . In other words, the reach-through voltage is made equal to the collector supply voltage in this design of the asymmetric IGBT structure.
3.6.1. Optimum Structure Design
The reach-through voltage is a function of ...