Simulation Design And Manufacture Of SiC BJT

Silicon Carbide is a third-generation wide bandgap semiconductor material and has unparalleled advantages over silicon.Compared with silicon materials,SiC material has a breakdown electric field of 10 times,a thermal conductivity of 3.3times,and a saturation of 2 times.The electron drift speed is an ideal materia l for the preparation of high temperature,high frequency,and high power devices.Among them,Silicon Carbide Bipolar Junction Transistor?SiC BJT?has drawn more and more attention due to its characteristics of high temperature resistance,low on-resistance,and fast switching speed.It has become a hot topic in the research of SiC power electronic devices in recent years.By analyzing the influence of cell structure parameters of SiC BJT on the current gain,the various structural parameters of the traditional cell are optimized,and analyzes the influence of the emitter,base,and collector regions of the SiC BJT on the current gain of the device.The effects of surface traps on current gain and specific on-resistance are given through simulations.In view of the interface complex current caused by the 4H-SiC BJT interface state studied by the academic community,two novel device structures that suppress the composite current are proposed.The simulation results of current gains of 50 and 65 were achieved by injecting a high-doping doping structure and a novel dual-base structure on the surface of the base region,respectively.Finally,the simulation of the effect of minority lifetime on device performance is studied.It can be seen that increasing the em itter area,the minority carrier lifetime of the base area can increase the current gain of the device,but considering the breakdown voltage and the switching speed of the device,it is necessary to comprehensively consider the influence on the device per formance.For the termination problem study of the device,the GR termination and the JTE termination are designed and optimized respectively,and points out their advantages and disadvantages.Based on this,a new type of termination JTE-GR termination is proposed and the structural parameters are optimized.The simulation can find that the breakdown voltage reaches 3200V at a terminal length of 120?m at normal temperature.The new JTE-GR termination can ensure the high efficiency and stability of the device termination at the same time,and it is not affected by the high temperature and the fixed charge of the oxide layer,and can be a good choice for future device termination.Based on the optimization of the cell size of the traditional SiC BJT,the design of the termination and the exploration of the SiC BJT process conditions,this paper successfully developed a stable 4H-SiC BJT.Leakage current 1.0×10^-4A/cm² as the device breakdown standard,the breakdown voltage has reached the effect of 1500V,exceeding the expected 1200V voltage standard.The current gain of the power BJT has reached around 13 which is in line with the previous simulation results because the surface trapping effect causes the surface recombination current to be large.This will cause the base current to increase and thus the current gain will be small.In the later period,we can improve the quality of the interface state.And the new structure that suppresses the composite current continues to improve its current gain in both aspects.