Injection ionization mechanism of current instability during switching off an integrated field controlled thyristor

The process of switching off an integrated field-controlled thyristor chip operating in a circuit with inductive load has been experimentally and theoretically analyzed. It was established by independent measurements of the anode and cathode emitter currents that the electron injection in all unit cells of the structure cannot be instantaneously interrupted under real conditions due to the shunting of the controlled emitters through the external circuit; the maximum current that can be switched off in this mode was also determined. A numerical simulation has revealed instability of the current distribution over the operation region, which facilitates its emergency localization, and has shown an urgent need to reduce stray inductances and resistances in the chips and shunting circuit when designing high-voltage integrated thyristors and related power modules.