The influence of bulk parameters on the switching behavior of FWDs for traction application

We investigate the performance of free wheeling diodes (FWDs) for traction application. Since there is experimental evidence of well designed junction termination, we concentrate on bulk effects. By numerical simulation the influence of bulk doping and base width on the dynamic characteristics of FWDs is analyzed. As limiting criterium for snap-off behavior the reach-through of the space-charge region to the nn/sup +/-emitter region is found. Measurements are in good agreement with the simulations.