Wu Di

Improved trade-off characteristics of 3.3kV fast recovery diode with optimized carrier distribution used for power systems

This paper presents an innovative method to optimize the excess carrier distribution in 3.3kV fast recovery diodes (FRDs). The idea is to develop a structure that can effectively optimize the anode emission efficiency. Based on TCAD simulation, two new structures, namely, local emitter control (LEC) diode, local emitter control and local lifetime control (LELC) diode, have been developed with improved trade-off characteristics between reverse recovery current peak and forward voltage drop compared with conventional diodes. The LEC diodes demonstrate the improved trade-off characteristics through introducing a wavy-type P-body that produces a low minority carrier density at P-body/N-sub side and a high minority carrier density at N-sub/N+ side. Through introducing an addition local lifetime control layer in combination with a wavy-type p-body, the LELC diode has demonstrated the best balanced properties of the forward voltage drop(VF), the reverse recovery current peak(Irr), and the softness without at the expense of increasing leakage current. The forward voltage drop of LEC diode and LELC diode are respectively decreased by 23% and 35% compared with conventional diodes. The surge current of LELC diode is 2 times larger than that of conventional and LEC ones.