Analysis And Optimization Of Short-circuit Characteristics With Dual-deep Trench SOI-LIGBT

Compared with the conventional intelligent power module,the Monolithic intelligent power chip integrates the control module and power devices,which realizes the miniaturization and intelligence of the whole system with smaller chip size.The Silicon-On-Insulator Lateral Insulated Gate Bipolar Transistor(SOI-LIGBT)is the key power component in the Monolithic intelligent power chip because of the superior performance in terms of current,breakdown voltage and control.However,the device may fail and cause the whole chip to be destroyed under the short-circuit stress,so its short-circuit robustness determines the reliability and application range of the chip.Therefore,the optimization of short-circuit robustness of SOI-LIGBT makes a lot of sense.Based on the dual-deep oxide trench SOI-LIGBT device,the short-circuit robustness has been optimized.It is found that the short-circuit failure of the dual-deep oxide trench SOI-LIGBT is caused by the deep trench,which limits the current path of the device and the carriers are concentrated at the bottom of the trench.The carriers concentration causes heat accumulation at the bottom of the trench,and the local temperature at the bottom of the trench is too high and dynamic avalanche occurs at the collector eventually.By reducing the depth of trench,the current path at the bottom of the trench is expanded,which alleviates the carriers concentration and the risk of dynamic avalanche at the collector is also reduced.Moreover,the emitter-side conductive trench is introduced to increase the hole heat flux diffusion path.This thesis also adopts the P~+/N~+interval emitter structure,and P~+emitter can effectively absorb the hole current flowing to the emitter and suppress the dynamic latchup.The simulation results show that breakdown voltage of the optimized dual-deep oxide trench SOI-LIGBT is560V,turn-on voltage is 1.8V,turn-off time is 132ns,and the device has a short-circuit withstand time of 9.8?s under the bus voltage of 450V,which meets the design specifications.