Numerical Analysis of Impact of Shield Gate on Trench IGBT and CSTBT

Numerical analysis of impact of shield gate (SG) on trench IGBT (TIGBT) and CSTBT are performed in this paper. The shielding effect provided by the SG in the trench bottom reduces the gate-collector capacitance $(C_{gc})$ and gate charges $(Q_{g})$ of the device with the cost of increased on-state voltage drop $(V_{ce(on})$). The impact of the SG on the device performance is quite different for the two SG-devices. Simulation results show that compared with conventional CSTBT, the SG-CSTBT has better trade-off relationship between turn-off loss Z $(E_{off})$ and $V_{ce(on)}$. However, for the SG-TIGBT, the trade-off relationship between $E_{off}$ and $V_{ce(on)}$ is worse than that of the conventional TIGBT.