Design criteria for Amplifying Gates on triode thyristors

Amplifying Gate Thyristors are thyristors with an auxiliary thyristor integrated between the gate and main thyristor in order to enhance uniformity of turn-on and, hence, di/dt capability. In order to obtain the full benefits of enhanced di/dt capability, thyristors should be designed to turn on at the auxiliary thyristor, rather than the main thyristor in all the following conditions: 1) gate turn-on, 2) dv/dt triggering, and 3) forward blocking voltage breakover. Further, proper turn-on for the latter two conditions should occur for an external gate to cathode impedance that may be experienced in application. We have established models for calculating the maximum potential of both the auxiliary and main thyristors as a function of device design parameters, including topological geometries, resistivities of the various regions, junction depths and basewidths. A computer program was designed for determining the current distributions and potentials as a function of external gate to cathode impedance.