FUNDAMENTAL MODELING OF THE TURN-OFF BEHAVIOR OF POWER BIPOLAR-TRANSISTORS

The 2-D device simulator, Hector, has been extended to model time dependent device behaviour in the presence of multiple circuit boundary conditions. Results are presented from a study in which Hector was used to investigate the turn-off of a power bipolar transistor. Two distinct forms of plasma removal are demonstrated, the dominant mechanism depending on the switching conditions. Also, other features in the I-V waveforms are explained in terms of interaction between the device structure and the switching circuit. Experimental results are shown to agree qualitatively with the simulations. Finally, this modelling work reveals inadequacies in the conventional discretisation schemes used in the solution of the semiconductor device equations. © 1990.