Temperature Dependence Modeling and Design Optimization of VCEsat in Carrier-Storage Trench-Gate IGBTs

Insulated-gate bipolar transistor (IGBT) power modules suffer efficiency degradation at elevated operating junction temperatures. The thermal sensitivity of the collector–emitter saturation voltage (VCEsat) induces thermal stress imbalance, constraining system efficiency and reliability. A multi-resistor cascade network model for carrier-storage trench-gate IGBTs (CS-IGBTs) is established. The simulation results agree with the measurements within 10% error. The model decomposes the temperature coefficient contributions of individual structural regions. Analysis reveals that the drift region resistance dominates the VCEsat temperature coefficient. Based on this finding, a co-doping strategy is proposed through simultaneously increasing the doping concentration in the carrier-storage layer and P+ collector. This approach reduces the temperature sensitivity of carrier mobility in the drift region, thereby optimizing VCEsat’s temperature sensitivity. For the fabricated 1200 V/40 A CS-IGBT, the VCEsat temperature coefficient decreases from 2.38 mV/K to 1.76 mV/K over 300 K to 450 K, which represents a 25.4% reduction. The total switching loss at 450 K decreases from 9.32 mJ to 8.70 mJ, achieving a 6.7% improvement. This device-level optimization suppresses VCEsat’s temperature sensitivity and switching losses, enhancing efficiency in high-temperature power module applications.