Experimental demonstration and theory of a solution to second breakdown in Si power transistors

This paper reports experimental measurements on second breakdown behavior of transistors which were altered from conventional structure so as to allow the addition of externally mounted, variable resistors to a finely divided emitter. It is found that forward-biased second breakdown can be eliminated so as to allow a typical four to six fold increase in the power available at high voltages. With suitable resistances, the safe-power vs. voltage curve becomes a straight line, allowing the transistor power dissipation to be thermally limited at all voltages rather than second break limited at higher voltages.