On the scaling limit of the Si-IGBTs with very narrow mesa structure

The very narrow mesa structures based on our 7th generation IGBT process are fabricated and it is found that the device with the narrowest mesa shows very poor short circuit (SC) withstand capability although it suppresses the conduction loss considerably. This poor SC capacity is caused by non-saturated output characteristics which are originated by collector bias induced barrier lowering in the middle of Si mesa. The current filamentation is observed in the 3D multi-cell short circuit simulation with self-heating and the SC capacity degradation due to the filamentation is enhanced in the narrower mesa structure.