Schottky Diode

This is a special type of diode in which a PN junction is replaced by a metal semiconductor junction. The P-type semiconductor in a normal PN junction diode is replaced by a metal and N-type material is joined to the metal. This combination has no depletion region between them. The following figure shows the Schottky diode and its symbol.

The metal used in this Schottky diode may be gold, silver, platinum or tungsten etc. As well, for the semiconductor material other than silicon, gallium arsenide is mostly used.

Operation

When no voltage is applied or when the circuit is unbiased, the electrons in the N-type material has lower energy level than the ones in the metal. If the diode is then forward biased, these electrons in the N-type gain some energy and move with some higher energy. Hence these electrons are called as Hot Carriers.

The following figure shows a Schottky diode connected in a circuit.

Advantages

There are many advantages of Schottky diode such as −

• It is a unipolar device and hence no reverse currents are formed.
• Its forward resistance is low.
• Voltage drops are very low.
• Rectification is fast and easy with the Schottky diode.
• There is no depletion region present and hence, no junction capacitance. So, the diode gets to OFF position quickly.

Applications

There are many applications of Schottky diode such as −

• Used as a detector diode
• Used as a Power rectifier
• Used in RF mixer circuits
• Used in power circuits
• Used as clamping diodes