The internal structure of fast recovery diode is different from ordinary PN junction diode, which belongs to PIN junction diode, i.e., the base region I is added in the middle of the P-type silicon material and N-type silicon material to form the PIN silicon wafer. Because the base region is very thin, the reverse recovery charge is very small, so the reverse recovery time of the fast recovery diode is shorter, the forward voltage drop is lower, and the reverse breakdown voltage (withstand voltage value) is higher.