An improved understanding for the transient operation of the power insulated gate bipolar transistor (IGBT)

It is shown that a nonquasi-static analysis must be used to describe the transient current and voltage waveforms of the insulated gate bipolar transistor. The nonquasi-static analysis is necessary because the transport of electrons and holes are coupled for the low-gain, high-level injection conditions, and the quasi-neutral base width changes faster than the base transit speed for typical load circuit conditions. To verify that both of the nonquasi-static effects must be included, the predictions of the quasi-static and nonquasi-static models are compared with measured current- and voltage-switching waveforms. The comparisons are performed for different load circuit conditions and for different device base lifetimes