A survey of second breakdown

The existence of a "new high current mode of transistor operation", now generally known as second breakdown, was first reported by Thornton and Simmons in 1958 and was used to explain the mysterious failures that were observed to occur under certain operating conditions. Since then, with the production of higher power and higher frequency transistors, the problems resulting from the existence of second breakdown have proliferated. Interest in the phenomenon has grown concurrently and many papers about second breakdown can be found in the literature. These papers cover a range of interest that extends from theoretical studies of the basic mechanisms involved to interpretations of specifications for transistor operation free of second breakdown. A complete understanding of second breakdown has not yet been achieved and several concepts of second breakdown prevail. The purpose of this paper is to review the work that has been reported in order to present a coherent and comprehensive picture of the present status of second breakdown.