Evolution of current filaments limiting the safe-operating area of high-voltage trench-IGBTs

An improved understanding of the physical processes leading to the formation of current filaments and latch-up in large arrays of monolithically integrated high voltage (3.3kV) trench-IGBT cells during the turn-off process of the device is the prerequisite for enhancing the robustness of the device. To this end, numerical simulations have been performed revealing the rim of the safe-operating area (SOA) and what happens beyond it.