The Simulation Study And Optimization Design On 4H-SiC Trench Field Stop IGBT

With the development of power electronics and information and communication technology,the performance of traditional silicon-based power devices has been unable to meet the application requirements of high power density.In recent years,silicon carbide material has attracted wide attention because of its superior material properties than traditional silicon material.Among many silicon carbide power devices,silicon carbide IGBT has become the core device for the future development of power semiconductor devices because of its characteristics such as simple drive,small conduction loss,high voltage resistance and high power density.This paper by using the theoretical analysis of the working principle of IGBT,all kinds of characteristics of IGBT are introduced,and then the Sentaurus-TCAD software was used to simulate three kinds of silicon carbide trench field stop IGBT(C-IGBT,GS-IGBT,FS-IGBT).Their characteristics are analyzed and compared under the minimum voltage standard of 12 k V.Finally,it is concluded that FS-IGBT has the best performance among the three devices.On this basis,the device defects of FS-IGBT are further analyzed,and the necessity of device optimization is illustrated.In this paper,based on FS-IGBT device,a new type of IGBT with P-type buried layer(BP-IGBT)is proposed by injecting two P-type buried layers at the side wall boundary of the top of the drift zone.Then,the doping concentration,length and thickness of the two P-type buried layers of BP-IGBT are simulated and optimized,and the optimal values of each parameter are determined.Then the Sentaurus-TCAD software was used to compare the static,dynamic and tradeoff characteristics between the BP-IGBT and FS-IGBT.The simulation results show that the breakdown voltage of BP-IGBT is about 11% higher than that of FS-IGBT in terms of static characteristics,and the maximum increase of the breakdown voltage can be up to 135% by changing parameters.At 300 K,the characteristic on-resistance of BP-IGBT decreased by about 47.9% compared with FS-IGBT,and the on state voltage of BP-IGBT decreased by about 27.6% compared with FS-IGBT under the same blocking voltage capability.When the temperature is 450 K,the on state voltage of BP-IGBT is 34.6% lower than that of FS-IGBT.In terms of dynamic characteristics,the turn-on power consumption of BP-IGBT is 65.2%lower than that of FS-IGBT,and the total switch power consumption is 17.9% lower than that of FS-IGBT.Under the same current overshoot,the turn-on power consumption of BPIGBT is reduced by 31.4% compared with FS-IGBT.At the same turn-off loss,the on state voltage of BP-IGBT is 33.4% lower than that of FS-IGBT.In terms of frequency characteristics,with the duty cycle increasing from 10% to 90% at 5 k Hz,the total dissipation power of BP-IGBT decreases from 20.7% to 30.4% compared with FS-IGBT when both of them work at 5 k Hz.The total dissipation power of BP-IGBT decreases from19.4% to 26.6% compared with FS-IGBT when both of them work at 10 k Hz.The final results show that the proposed BP-IGBT with P-type buried layer is more suitable for high voltage power applications than the FS-IGBT.