The measured turn-off waveforms of 4.5 kV SiCGTs by using electron irradiation with various electron doses are reported. The turn-off time decreased with an increase in the electron dose. Furthermore, the turn-off characteristics of SiCGTs with p-type drift layer, which assumed the various trap concentrations, are simulated. The relation between the turn-off characteristics and the trap is also investigated. The simulated results show good correlation to measured data and the simulated turn-off times decrease with an increase in the electron dose as well as measured data.