We investigated the turn-off waveforms of Superjunction (SJ) silicon MOSFETs with respect to their own charge imbalance by experiments as well as by device simulations.
When SJ-MOSFETs are used for chopper circuits we find a unique hump in the current waveform during the turn-off transient. The magnitude of the hump shape waveform drastically depends on the charge imbalance (CIB) in the SJ structure.