A field terminated diode

The field terminated diode (FTD) is a new medium power switching element which meets the important criteria of a switching thyristor: fast switching and low conduction losses. Two types of devices are described, the FTD itself, which is used in commutated turn off applications, and a gate turn off variation of the FTD called the field controlled thyristor (FCT). These are three terminal devices, and forward blocking is achieved by applying a reverse bias to the grid with respect to the cathode; reverse blocking is accomplished at the anode junction. Both devices are described, and their performance is compared to that of transistors and conventional switching thyristors.