The Reverse Recovery Mechanism refers to the fact that when a diode switches from the positive on state to the reverse off state, the few charge carriers (such as electrons and holes) stored in the diode will cause the reverse current to be generated until these carriers are completely removed. This process is called reverse recovery time (trr).

The detailed process of reverse recovery mechanism:
Positive wizard status:
  When the diode is in a forward bias, the current passes through the diode, and the PN junction region inside the diode will be filled with forward flowing electrons and holes.
      When the forward current passes through, a small number of carriers (electrons and holes) inside the diode are injected into the PN junction region, causing the hole region and electron region of the PN junction to form a "carrier storage region".
Reverse switch:
      When the applied voltage changes from forward to reverse, the diode should stop conducting electricity.
     However, because the charge carriers (electrons and holes) inside the diode do not disappear immediately, they continue to flow for some time, resulting in a brief reverse current.
     Reverse recovery period:
     After the reverse voltage is applied, the electrons and holes in the diode are slowly removed, a process that takes a certain amount of time, known as reverse recovery time (trr).
     During this period, a reverse current will flow through the diode, called the reverse recovery current. This reverse current continues for some time until the stored carriers are completely dissipated.
     Reverse current and recovery process:
     During reverse recovery, the amount of current depends on the number of carriers stored and the characteristics of the diode. Typically, this reverse current drops rapidly until it returns to a state of zero current.
     The shorter the reverse recovery time, the better the reverse recovery characteristics of the diode, which is suitable for high-speed switching applications.
     Effects of reverse recovery:
     Switching loss: In switching power supplies, inverters and other applications, the reverse recovery current of the diode will cause a certain amount of energy loss, especially in the process of high-frequency switching, this loss will increase significantly.
     Generate electromagnetic interference (EMI) : A sudden change in the reverse recovery current may generate high-frequency electromagnetic interference, requiring additional filtering or suppression measures.
     Diode selection: In high frequency applications, in order to reduce reverse Recovery time, it is common to choose diodes with Fast recovery characteristics (such as Schottky diodes) or use specialized fast recovery diodes that are designed to reduce reverse recovery current and recovery time.

Factors affecting the reverse recovery time:
  Temperature: As the temperature increases, the reverse recovery time usually increases because the carrier lifetime of the semiconductor material becomes longer at high temperatures.
      Current size: A larger forward current usually results in a larger reverse recovery current and a longer recovery time.
      Types of diodes: Different types of diodes (such as ordinary diodes, Schottky diodes, fast recovery diodes) have different reverse recovery characteristics, and fast recovery diodes have shorter reverse recovery times than ordinary diodes.