Transient switch-off of a 4H-SiC bipolar transistor from the deep-saturation mode

Abstract

The transient switch-off of a bipolar 4H-SiC transistor from the deep-saturation mode is studied by performing 1D numerical simulation. Switch-off in the zero base current mode and in the mode of switching-off with a negative base current is examined. It is shown that at quite real values of the switching-off base current, the switch-off time can be made ~40 times shorter than the switch-off time at zero base current. The delay time can also be made substantially (several times) shorter. It is noted that, in the deep saturation mode in which the conductivity of the collector layer is highly modulated by minority carriers, the bipolar transistor can operate in the continuous mode at a rather high current density.