Advanced lifetime control for reducing turn-off switching losses of 4.5 kV IEGT devices

To decrease the switching losses and improve the trade-off between conduction and switching losses, local lifetime control by proton irradiation is applied to IEGT (injection enhanced gate transistor) devices. However, the maximum amount of lifetime reduction is limited by the phenomenon of negative resistance in the I-V characteristics, which causes problems if paralleling the devices. In this paper, we propose an analytical treatment of the phenomenon of negative resistance and propose lifetime profiles which allow the operation of IEGT devices with significantly reduced turn-off losses, while maintaining a smooth I-V characteristic without negative resistance.