What is the difference between Schottky and Fast Recovery Diode?

Thanks
i want to more.
isn't schottky a fast diode?why we produce another pn diode that said fast recovery diode?

Sottky diodes are fast, they can be used well into microwave frequencies (some gigahertz) but usually don't witstand large currents and are prone to electrostatic charge damage.

Fast recovery silicon diodes are usually much more rugged, it is the type of diode you find in SMPS (just an example). Found this excellent write-up on the difference, rather than trying to write the book myself. Enjoy!

"A fast recovery diode stops conducting quickly when a reverse charge in imposed across it's junction. The quicker the better, as this limits the voltage transient and associated ringing resulting from a change in current across the internal inductance of the diode and it's leads (di/dt). In practice, even with a super fast recovery silicone diode, such as that exhibited by the popular 1N914, a voltage transient will still be created since the recovery event is fast (di/dt again). Our semiconductor industry addresses this by designing a "fast-soft recovery" characteristic into some of their diodes and these have generally garnered wide acceptance. Snubber networks further mitigate the negative effects of di/dt.

A schottky diode incorporates a different junction topology which produces a lower voltage drop associated with it - thus lower power loss and better efficiency. The recovery is fairly fast, and happens to exhibit an indigenous fast-soft recovery characteristic making it near ideal for many switching applications. But, in general it is the low forward drop that generally marks this device for a specific circuit application. Schottky diodes have a couple of undesirable attributes. They exhibit a higher leakage current than their silicon junction brethren, as well as limited blocking voltge due to their junction structure. These two characteristics often negate it from being used in many applications."

Excerpt from Fast recovery vs. Schottky diodes

soft turnoff.

ClassD said: However if you are using the diodes in a standard 50Hz bridge rectifier then there will really be no diffrence because the frequency is so low.

I used to think so too. Get your scope out and have a look at the transformer secondary voltage under load. Zoom in to where the waveform is just starting to move away from the flattened peak and head toward zero again. As a slow diode recovers it will "snap" the reverse recovery current off suddenly, causing the transformer winding to ring somewhat. Fast, ultrafast and schottky diodes (and vacuum tube rectifiers for that matter) turn off more cleanly and don't "twang" the transformer winding and generate noise in the process.