Metallurgically bonded, glass-bodied DO-35 power rectifier diodes were electrically overstressed by applying forward and reverse current pulses. Forward current pulses varied from 0.1 to 3 ms with current amplitudes varying from 200 to 1000 A were applied to one group of diodes.  Reverse bias current pulses in the microsecond range with amplitudes from 2 to 400 mA (above breakdown voltage) were applied to another group. A small-step cross sectioning in combination with electrical probing, light emission microscopy, liquid crystal technique, and chemical staining were used to reveal and compare damage in three groups of diodes: two overstressed groups and the third group which had failed during burn-in electrical testing.

Failure mechanisms and peculiarities of damage created in these diodes and several case histories related to different types of diodes are discussed.