High voltage bipolar transistor with new concepts

The 200 A class bipolar transistors developed for 440 V AC line use have two-stage Darlington construction to accomplish the low power loss, V_CE(sat)=1.5 V, t_f⩽1 μs. The destruction current in the reverse bias safe operation area (SOA) is expanded to twice the conventional. This improvement is based on the theoretical prediction and the experimental confirmation that the operating limit voltage is determined by the collector layer thickness, and the operating limit current density is determined by the resistivity of the collector layer. The necessary condition for obtaining a wide short-circuit SOA is presented