ADVANCED RBSOA ANALYSIS FOR ADVANCED POWER BJTS

Performances of some modem power BJT's in inductive turn-off are exper imentally evaluated, by means of an unclamped non-destructive method. The different instabilities exhibited are classified and their influen ce on device performances is discussed both in clamped and unclamped a pplications. An ''Instability Map'' is proposed both as a synthetic pi cture which eases comparison of reverse-bias performances of devices h aving different ratings, and as an investigation tool for linking devi ce behaviour to its physical features. It results that RBSOA performan ces are not just related to lateral dimensions of the emitter, but als o to metallization lay-out of the chip, which evidently influences cur rent distribution among cells. Finally, stray elements of testing circ uit which affect results of RBSOA measurements are investigated, and s ome suggestions are proposed in order to let measurement results becom e independent of testing circuit. Copyright (C) 1996 Elsevier Science Ltd.