Turn-off dV/dt controllability is an essential feature in insulated gate bipolar transistors (IGBTs) for flexible design in power switching applications. However, the occurrence of dynamic avalanche (DA) during the turn-off transients plays a key role on the turn-off power loss, dV/dt controllability and safe operating area of IGBTs. This article aims to clarify the impact of DA on the turn-off characteristics of 1.2-kV trench IGBTs through three-dimensional technology computer aided design (TCAD) simulations as well as experimental demonstrations. Measurement results show that DA is enhanced at high current density and high supply voltage conditions, which aggravates its influence on the dV/dt controllability as well as turn-off power loss. To eliminate the DA for high current density and low loss operations, a DA free design is experimentally demonstrated in the Trench Clustered IGBT (TCIGBT). Due to effective management of electric field and unique p-channel metal oxide semiconductor (PMOS) actions during turn-off, TCIGBT can retain high dV/dt controllability and low power loss at high current density operations.
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