Cathode Emitter versus Carrier Lifetime Engineering of Thyristors for Industrial Applications

摘要

We experimentally demonstrate that the traditional way of reducing the recovery charge Qrr by electron irradiation can be replaced by appropriate density of cathode shorts of an appropriate size. Functionality of this approach is demonstrated for the thyristors of 1.8 and 2.8 kV voltage classes, for which an improvement of technology curve Qrr - VT was achieved. In addition, the higher density of cathode shorts improves the dV/dt capability and circuit commutated recovery time tq. The Irradiation Free Concept provides thyristors with improved ratings, while it eliminates the fear of annealing the radiation defects from electron irradiation under overload conditions, when thyristors are repeatedly exposed to ON-state currents close to the nominal value of surge ON-state current ITSM.