Do Schottky barrier diodes (SBDs) have reverse recovery time (trr)?

Unlike pn junction diodes, Schottky barrier diodes operate with majority carriers only, so in principle there is no reverse recovery time. However, there is a slight reverse recovery time due to parasitic capacitance, etc.

When forward-biased, pn junction diodes turn on as electrons, minority carriers, flow into the p-type semiconductor while holes flow into the n-type semiconductor. Since both electrons and holes contribute to device operation, pn junction diodes are called bipolar devices. On the other hand, in the case of an SBD composed of an n-type semiconductor and a metal, majority carriers flow into the metal when the SBD is forward-biased, causing it to turn on. Since only majority carriers contribute to device operation, SBDs are called unipolar devices.
Bipolar type diodes, such as p-n junction diodes, have a low concentration N-layer to increase the device's breakdown voltage. This layer acts as a resistor when turned on, which has the disadvantage of increasing forward voltage. However, in actual operation when turned on, a large amount of holes flow from the P+ layer on the anode side into the N- layer. At the same time, a large amount of electrons are supplied from the cathode side to maintain electrical neutrality. As a result, a large number of carriers temporarily exist in the N- layer, resulting in a low resistance value. This is called conductivity modulation.
This is good in terms of lowering the on-voltage (forward voltage) of the device, but it also has the disadvantage that it cannot be turned off immediately (it takes time to turn off). This is because a large number of minority carriers (holes) that have entered the N-layer due to conductivity modulation have nowhere to go, and it takes time for these excess minority carriers to disappear through recombination. This period is called the reverse recovery time, and a reverse current flows. In contrast, in the case of SDBs, the minority carriers of the n-type (or p-type) semiconductor do not contribute to device operation. Therefore, SBDs exhibit no reverse recovery time. However, considerable surface leakage occurs since SBDs consist of a heterogeneous junction between a metal and a semiconductor. In some SBDs, a pn junction is sometimes used to reduce this leakage. In addition to this, it has parasitic capacitance, so it may have a reverse recovery time, although it is minute compared to a pn junction diode.
Conductivity modulation is explained in the e-learning below. please refer.
e-learning:Basics of Schottky Barrier Diodes 2-3. Conductivity modulation

Fig. 1 Diode state when forward biased
Fig. 1 Diode state when forward biased
Fig. 2 SiC SBD vs Si pn junction diode  Turn-off waveform
Fig. 2 SiC SBD vs Si pn junction diode Turn-off waveform

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