Distinguishing Schottky Diode from Fast Recovery Diode — SUNMATE

1. The structure principle is different. Schottky diode is a combination of precious metal and n-type semiconductor, and fast recovery diode is a common pn junction with a thin base.

2. Fast recovery diode refers to a diode with a very short reverse recovery time (below 5us). Gold doping measures are mostly adopted in the process. PN junction structure is adopted in the structure, and some adopt improved PIN structure. Its forward voltage drop is higher than that of ordinary diodes (1-2V), and its reverse withstand voltage is mostly below 1200V. In terms of performance, it can be divided into two levels: fast recovery and ultra fast recovery. The former has a reverse recovery time of hundreds of nanoseconds or longer, while the latter has a recovery time of less than 100 nanoseconds. Schottky diode is a diode based on the potential barrier formed by the contact between metal and semiconductor. It is called Schottky Barrier Diode. It has a forward voltage reduction (0.4-0.5V), a short reverse recovery time (10-40 nanoseconds), and a large reverse leakage current, low voltage withstand, generally less than 150V. It is mostly used in low-voltage occasions.

3. The reverse breakdown voltage of Schottky diodes is mostly not higher than 60V, and the maximum is only about 100V. Its use is limited. The reverse peak value of fast recovery diodes can reach hundreds to thousands of volts. Therefore, for example, high-frequency rectifier diodes with 100V or more in the secondary of switching power transformers, only fast recovery (UFRD) is used.

4. The Schottky positive conduction voltage drop is only about 0.4V, and the fast recovery secondary hall is 0.6V. In general, because the storage effect of a few carriers in the Schottky diode is very small, its frequency response is only limited by the RC time constant. Therefore, it is an ideal device for high frequency and fast switching. Its operating frequency can reach 100GHz. In addition, MIS (metal insulator semiconductor) Schottky diodes can be used to make solar cells or light-emitting diodes. Fast recovery diode: with 0.8-1.1V forward conduction voltage drop and 35-85nS reverse recovery time, it can quickly switch between conduction and cut-off, improving the use frequency of the device and improving the waveform. High switching speed and high voltage withstand can be achieved by using gold doping and simple diffusion in the manufacturing process of fast recovery diode. At present, fast recovery diode is mainly used as rectifier in inverter power supply.