Two-dimensional numerical analysis of turn-off process in a GTO under inductive load

The turn-off process for a gate turn-off thyristor (GTO) with a shorted anode emitter is analyzed under an inductive load with high applied voltage using a two-dimensional numerical model. The role of the shorted anode emitter is discussed in conjunction with the current-flow lines. Furthermore, the behavior of plasma squeezing and the electric field under high applied voltage are investigated. Plasma squeezing during the storage period is relieved during the fall period due to the hole-current component generated overall of the center junction by the extension of the depletion layer. The hole-current component causes an increase in space-charge density which in turn generates a high electric field around the center junction. At the same time, the electron-current component causes a reduction in space-charge density in the n-base side. Therefore, the electric field under the cathode is lower than under the gate; however, its value becomes over 100 kV/cm. On the other hand, temperature rise is low.