Silicon diode: Use of P-doped silicon and N-doped silicon to make a P-N junction that causes the blocking effect
Schokky diode: Use of (normally) P-doped silicon bonded to metal. The junction effect is at the metal connection and it is because only one doped-tpye of silicon is used you end up with the lower on-state.
Schottky generally has lower reverse voltage max. You can easily find silicon diodes with 20-1400v ranges, while commonly schottky is 20v-60v.
Schottky is extremely fast recovery, even faster than so-called “fast recovery” silicon diodes. So you can use them in high frequency SMPS.
Forward voltage drop is lower. In silicon you get 0.6v-0.7v at rated current. In schottky you can get 0.3v which is great for SMPS.
Most schottky diodes look exactly the same is a regular diode.
|COMPARISON OF CHARACTERISTICS OF SCHOTTKY DIODE AND PN DIODE|
|CHARACTERISTIC||SCHOTTKY DIODE||PN JUNCTION DIODE|
|Forward current mechanism||Majority carrier transport.||Due to diffusion currents, i.e. minority carrier transport.|
|Reverse current||Results from majority carriers that overcome the barrier. This is less temperature dependent than for standard PN junction.||Results from the minority carriers diffusing through the depletion layer. It has a strong temperature dependence.|
|Turn on voltage||Small – around 0.2 V.||Comparatively large – around 0.7 V.|
|Switching speed||Fast – as a result of the use of majority carriers because no recombination is required.||Limited by the recombination time of the injected minority carriers.|
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