A Study of parasitic oscillations in trench IGBT during short-circuit type II based on signal flow graph model

Abstract:
The oscillation phenomenon of trench-type insulated gate bipolar transistors (IGBTs) during short-circuit type II was experimentally investigated. The gate resistance required for oscillation suppression decreased with increasing collector voltage. The oscillation conditions were calculated from the signal flow graph model using the S-parameter based on a technology computer-aided design (TCAD) simulation. The calculation results reproduced the locus of the collector voltage dependence of the gate resistance measured experimentally. The oscillation mechanism was investigated. The response of the discharged carriers at the base-drift layer boundary was found to transmit to the collector side through the electron-hole plasma region during the oscillation. These results indicated that the transfer characteristics of the carrier distribution caused a collector voltage dependence of the short-circuit oscillation conditions.