A study of correlation between traps and reverse-recovery characteristics of FWDs

The purpose of this work is to clarify the correlation between traps and reverse-recovery characteristics of freewheeling diodes (FWDs). The traps induced in FWDs have been examined by deep level transient spectroscopy and the reverse-recovery characteristics of FWD with IGBT have been measured and simulated with a trap model. It was found that the difference in the concentration of traps with a shallow and with a deep energy level has a large influence on the reverse-recovery characteristics. Consequently, an increase in the concentration of the charged traps leads to lowering of the peak in voltage generated during reverse-recovery.