Effect of Back-P-Region on Reverse Recovery Oscillation Suppression in High-Voltage FRDs

The efficient transmission of electricity over long distance requires the use of high-voltage fast recovery diodes (FRDs). However, if not designed correctly, these diodes can lead to oscillation problems and damage to the device, potentially disrupting the operation of other devices in the system. Therefore, it is crucial to explore methods to suppress oscillation during the FRD reverse recovery process. In order to alleviate this problem, the FCE (Field Charge Extraction) diode, with a high-concentration $P^{+}$ region added to the cathode $N^{+}$ region, has been proposed. However, there is limited literature on the detailed mechanism of its oscillation suppression effect. In this paper, three-dimensional models of 4500-V high-voltage conventional FRD and FCE diode are established with Sentaurus TCAD tools. The mechanism of oscillation suppression is elucidated by studying the movement of internal carriers during reverse recovery. Simulation results show that the larger the proportion of the back P region, the better the reverse recovery softness of the diode, the more obvious the oscillation suppression effect.