Schottky Diode

What is Schottky Diode?

The Schottky Diode is an electronic component which is used to radio frequency (RF) functions like a mixer or a detector diode. It comes useful for functions having power because of possessing low forward voltage drop that would result in power loss at the least levels in comparison to the general PN junction diodes. In some cases, it is sometimes addressed as the surface barrier diode or hot carrier diode.

The other names of a Schottky diode are barrier diode, hot electron diode, hot carrier diode, majority carrier diode.

Table of Contents

  1. Symbol
  2. V-I-Characteristics
  3. Working
  4. Applications
  5. Advantages
  6. Disadvantages
  7. Difference

What is Schottky Diode Symbol?

The symbol for the Schottky barrier diode is based around the basic diode circuit symbol. The circuit symbol of the Schottky diode is shown in the figure.

Schottky Diode Symbol

Schottky Diode Symbol

 

V-I Characteristics of Schottky Diode

The V-I characteristics of Schottky diode are very much similar to the pn junction diode. Current is the dependent variable while voltage is the independent variable in Schottky diode. The forward voltage drop of Schottky diode is low between 0.2 to 0.3 volts.
VI characteristics of Schottky diode

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Working of a Schottky Diode

  • The operation relies on the principle that the electrons in different materials have different potential energy.
  • N-type semiconductors have higher potential energy than electrons of metals.

Schottky Diode Working

  • When these two are brought into contact, there is a flow of electrons in both directions across the metal-semiconductor interface.
  • A voltage is applied to the Schottky so that the metal is positive when compared to the semiconductor.
  • The voltage opposes the built-in potential and makes the current flow easy.

Applications of Schottky Diode

Schottky diodes have been useful for the industry of electronics that has spotted many applications in diode rectifier because of its unique properties. Here are some of the major areas where it is widely used.

RF mixer and detector diode:

The Schottky diode consists of its radio frequency functions owing to its switching speed at the highest level and top frequency capability. The Schottky barrier diodes come handy for diode ring mixers with high performance.

Power rectifier:

The Schottky barrier diodes also have functions with high power as rectifiers. The high density of current and voltage drop with low forward shows that the wastage of power is the least then the normal PN junction diodes.

Power OR circuits:

This diode would be useful for functions where two different power supplies drive a load like in battery supply. It is important that the power coming from supply should not mix with the others.

Solar Cell Applications:

As we know,  the solar cells are usually linked to the batteries that are rechargeable, mostly batteries with lead acid since power supply must be necessary round the clock. Solar cells would not support the applied charge in reverse and thus a diode would be used in a proportional pattern of the solar cells.

Advantages of Schottky diode

Following are the advantages of Schottky diode:

  • The capacitance of the diode is low as the depletion region of the diode is negligible.
  • The reverse recovery time of the diode is very fast, that is the change from ON to OFF state is fast.
  • The current density of the diode is high as the depletion region is negligible.
  • The turn on voltage of the diode is 0.2 to 0.3 volts which is very low.

Disadvantages of Schottky diode

The only disadvantage of Schottky diode is that the reverse saturation current of the diode is large.

What is the difference between Schottky diode and PN junction diode?

Schottky diode PN junction diode
In this diode the junction is formed between the n-types semiconductor and the metal plate In this diode the junction is formed between the p-type and n-type semiconductors
The forward voltage drop is low The forward voltage drop for pn junction diode is more
Reverse recovery loss and reverse recovery time are very less Reverse recovery loss and reverse recovery time are very more
It is a unipolar device It is a bipolar device
The conduction of current happens only due to the movement of electrons The conduction of current happens due to the movement of electrons and holes

Frequently Asked Questions on Schottky Diode

Why there is no reverse recovery time in the diode?

There are no stored charges as the metal-semiconductor junction is used, due to which the switching is faster.

What are the majority charge carriers in a barrier diode?

Electrons

Why Schottky diode can be switched off much faster than the p-n junction diode?

As there is no recombination of charges, there is no reverse recovery time which makes switching off faster.

What is reverse recovery time?

Reverse recovery time of diode is defined as the time taken by the diode to regain its blocking capability.

What is a blocking diode?

Blocking diode is a diode used to direct the energy flow in one direction in a wire.

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