Research On Minority Carrier Lifetime Control Method Of High Voltage FSRD

With the rapid development of the technology of high frequency power electronic circuit,the performance requirements for the main switching devices, such as IGBT, GTO and IGCT used in power electronic circuits are continuously improved, and what's more, the anti-parallel freewheeling diodes are also required with the excellent electrical properties and high reliability.At present, the improvements of the performance of high voltage fast soft recovery diodes(FSRD) are mainly realized by the structure optimization and the carrier lifetime control.The lifetime control technology has an important impact on its characteristics and reliability.In this paper, the recombination center properties of high and low energy electron irradiation and the effect of minority carrier lifetime on the device characteristics are analyzed.Then the different defect distributions induced by high and low energy electron irradiation and H+ radiation are investigated by CASINO and SRIM software. Finally, the effects of the different irradiation methods on the diode characteristic, dynamic avalanche and surge current characteristic are analyzed by ISE-TCAD simulator. The main research contents are as follows;Firstly, the requirement of minority carrier lifetime in high voltage FSRD is briefly described. And the defect level parameters produced by different irradiation methods are analyzed. In addition, the optimal position of the radiation level in the silicon and the influence of minority carrier lifetime on the device characteristics are analyzed.Secondly, the defect distributions induced by the electron irradiation of different energy in silicon are analyzed by the CASINO software to determine the device structure and physical model for simulation. The radiation model of high voltage FSRD is established by ISE-TCAD simulator, and the influence of defect distributions by high and low energy electron radiation of high voltage FSRD was studied.Thirdly, the defect distribution in silicon induced by H+ irradiation is analyzed by SRIM,and then the defect distributions induced by the combination of electron irradiation and H+irradiation are introduced into the high voltage diode.The influence of different defect distributions on the characteristics of the high voltage diode is studied by using the irradiation model in ISE-TCAD simulator.Lastly, the characteristics of FSRD under different irradiation conditions are compared,and the influence of different irradiation on the dynamic avalanche and surge current characteristic of the devices are analyzed.The results in this paper can provide certain reference for the design and development of high voltage fast soft recovery diodes.