IGBT turn-off characteristics explained through measurements and device simulation

IGBT turn-off waveforms have identifiable slope changes and particularities that can be attributed to device structure and circuit conditions. These phenomena are analyzed from test fixture results and actual application measurements. Physical relation of the device structure to the simulated and measured waveforms is presented allowing designers to interpret the effects of device structure on turn-off characteristics and ultimately the effects on switching losses. Based on the results presented, IGBTs can be optimized for various switching applications. All the pertinent parameters are extensively characterized. The double sloped VCE rise, the ICE pocket and current tail are emphasized for analysis as a function of electrical and thermal input parameters.