| As the application range of Insulated Gate Bipolar Transistor(IGBT)continues to expand,the matching freewheel diodes will also need to improve their characteristic and reliability.At present,the industry is most concerned about the fast and soft recovery characteristics and reliability of the freewheel diodes to meet the application requirements of IGBT module application.Based on the characteristics and reliability of 3.3kV Fast Soft Recovery Diode(FSRD),a new structure of FSRD(NCA-PC-FSRD)with n+adjusted region and corrugated composite anode(N adjusted Corrugated Anode,NCA)and p+adjusted cathode(P adjusted Cathode,PC)is proposed,the characteristics and reliability were studied by Sentaurus-TCAD software.The main research contents are as follows:Firstly,the mechanism of the p+adjusted cathode(PC),the n+adjusted anode(NA),the corrugated anode(CA)and its composite anode(NCA)on the conduction,reverse breakdown and reverse recovery of the diode were analyzed,the operation mechanism of NCA-PC-FSRD was studied based on this work.Secondly,the characteristics of NCA-PC-FSRD were simulated and compared with the FSRD characteristics of the common anode,NA,CA and NCA and the common cathode.The key structural parameters,such as the ripple height of the anode region,the window width of the anode region and the width of the p+adjusted region on the cathode side,the influence of the minority carrier lifetime and temperature on NCA-PC-FSRD characteristics,and the optimized structural parameters are extracted.Lastlly,the NCA-PC-FSRD ability to withstand to surge current capacity and dynamic avalanche abilities were investigated,compared with the conventional FSRD.The influence of the field limit ring and its resistance region on the reliability of NCA-PC-FSRD terminal is analyzed,and the junction terminal resistance region and back layout are optimized.The results show that the proposed NCA-PC-FSRD and its termination structure can effectively suppress dynamic avalanches and current concentration during reverse recovery,with excellent characteristics and reliability.The research results have certain reference value for the development of high pressure fast soft recovery diode. |
