Design Of 15 KV SiC Power IGBT

Silicon Carbide(SiC)has excellent performance,especially high critical electric field and high thermal conductivity,making it the most attractive material in power devices.The development of the 15kV silicon carbide IGBT(Insulated Gate Bipolar Transistor)makes it possible to develop new power electronics applications.Silicon carbide power IGBT device cell and its terminal structure design is one of the hot researches.In this thesis,computer-aided design(Technology Computer Aided Design,TCAD)software Silvaco was used to simulate and optimize 15kV silicon carbide power IGBT device cell and its terminal.The breakdown voltage,the threshold voltage and the on-resistance of the device are studied in this paper.The effects of the drift region length,the drift region doping concentration,the JFET region width,the current enhancement layer and the buffer layer on the device are studied to analyze the electrical performance of IGBT cell.The optimal structural dimensions of the electrical design index are obtained.In the study of the terminal structure,this paper chooses two terminal structures:junction termination extension and floating field ring.The influence of the structural parameters on the breakdown voltage is studied respectively.The operating principle and the breakdown characteristics of the two are compared to obtain terminal structure and its parameters.Finally,the high temperature characteristics of IGBT devices cell are simulated and compared,and we find that the static parameters and dynamic parameters of the devices are changed under high temperature and the principle is explained.The final simulation results show that the optimal silicon carbide IGBT device cell threshold voltage is 3.8V,the breakdown voltage is 18.2kV,the forward voltage drop is 17.5V,the on-resistance is56.5mf?·cm2,the input capacitance,output capacitance and reverse transfer capacitance are 598pF,17.5pF and 5.07pF,respectively.Terminal structure breakdown voltage is 18kV.The result has meet the design requirements,and obtained a good balance between the parameters.The research results of this thesis have some reference significance for the design of silicon carbide power devices.