Turn-off behaviour of epitaxial planar and trench gate IGBTs and nonepitaxial planar gate IGBT under hard and soft switchings

The results of investigation on turn-off dynamic operations of IGBTs are presented in the paper. Three-types of IGBTs which have planar and trench gate structures by epitaxial wafer and planar gate structure by nonepitaxial wafer are compared under conditions of hard and soft switching commutation topologies. Collector-emitter voltage and collector current waveforms of each IGBT and power losses are analysed under conditions of various parameters through simulation and in experiment. Moreover, carrier behaviour, electric field and potential distributions inside the chips are studied by simulation technique. It is noted that the trench gate IGBT has an advantage over the other-types for the hard switching application from the point of view of switching losses, and both the planar and trench gate IGBTs on the basis of an epitaxial wafer are more suitable for soft switching applications because of lower switching and on-state losses.