Second Breakdown and Damage in 1N4148 from Oscillating Electrical Transients

The conditions for initiating second breakdown in 1N4148 diodes were investigated with reverse-biasing square pulses following high forward injection (prestress). It was found that at a certain prestress the reverse voltage necessary for inducing second breakdown suddenly drops from the normal reverse breakdown voltage to about 20 percent of this value. At higher prestress the power necessary for junction damage from the reverse pulse is higher by more than an order of magnitude than without prestress, and no transition to second breakdown is observed. These results are not in agreement with present models of second breakdown and junction damage.