Design-dependent variability of pulse hardness of types of discrete semiconductor devices (intervendor variations)

The differences in the pulse hardness of several types of low power transistors due to different designs of each type were investigated. The pulse hardness is characterized by the power of a 1us square pulse of voltage necessary and sufficient to cause failure or second breakdown in a reverse biased junction. This power was determined by the process of step stressing for both the emitter to base and collector to base junctions. In one commercial type, the failure power of the collector to base junctions varied by more than four orders magnitude, and the failure power of the emitter to base junctions varied by more than two orders of magnitude. In two of the JAN types, a range of specimen failure powers of the collector to base junctions of more than three orders of magnitude was found; in one type, the mean values of samples varied by about a factor of 50. The variation of the failure powers of the emitter to base junctions in the JAN investigated was negligible. Design dependent variations of the failure levels of specimens of one type are thus possible that are orders of a magnitude larger than previously thought.