Safe operating area for bipolar transistors

OPERATION OF BIPOLAR transistors in high-power circuits is limited due to second breakdown failure mode in forward ( IB > 0, VCE < BVCEO) as well as reverse (IB < 0, BVCEO < VCE < BVCB~) operating regions. Nonuniformity of temperature and current distributions within the device and the avalanche injection from the collector region are believed to be the cause of second breakdown.