MODELING OF NONUNIFORM HEAT DISSIPATION AND PREDICTION OF HOT-SPOTS IN POWER TRANSISTORS

In this work a heat generation model induced by current crowding is pr oposed. This model, in turn, is applied to the thermal calculation of typical multi-finger emitter structures of BJTs. The internal temperat ure distribution obtained from this model provides clear indication of the existence of hot spots in base-emitter contact region. The charac teristics of the location and the magnitude of hot spots are also pres ented in this paper. Various pertinent effects due to the non-uniform heat dissipation are discussed. The result of this study serves to loc ate potential hot spots, which must be considered to prevent thermal b reakdown of power BJTs as well as other types of power devices. (C) 19 98 Elsevier Science Ltd. All rights reserved.