Schottky diode is a type of metal-semiconductor junction diode, also known as hot carrier diodes, low voltage diodes, Schottky blocking diodes, surface blocking diodes, and majority carrier diodes. A scientist named Walter H. Schottky first discovered the Schottky diode.
Generally in PN junction devices, connecting a positive type (p-type) and a negative type (n-type) forms a PN junction. However, Schottky diodes use materials such as aluminum and platinum instead of P-type semiconductors.
Features of Schottky Diode
- Low forward voltage drop
- Fast recovery time
- Low-loss energy at higher frequencies
- It is a Uni-polar device
Pinout of Schottky Diode
Working of Schottky Diode
Schottky diodes are primarily known for their fast switching speed and low forward voltage drop. Furthermore, there is no depletion layer at the junction between the metal electrode and the semiconductor, so the diode cannot store additional charge at the junction as it is for PN diodes. So every time the voltage drops, current flows directly through the diode.
V-I Characteristics of Schottky Diode
The V-I characteristics of Schottky diodes are very similar to PN junction diodes. In a Schottky diode, current is the dependent variable and voltage is the independent variable. Schottky diodes have a low forward voltage drop of 0.2 to 0.3 volts.
Uses
This type of diode mainly used as RF mixers, power rectifiers, etc. A major feature of Schottky diodes is their ability to reverse from a conducting state to a blocking state. Therefore, it is very useful in low turn-on voltage regions.
Advantages
- The diode capacitance is small because the diode depletion region is negligible.
- The diode reverse recovery time is very fast. That is, the transition from ON state to OFF state is fast.
- The diode has a high current density because the depletion region is negligible.
- The diode turn-on voltage is 0.2 to 0.3 volts, which is very low.
Disadvantage
- Reverse saturation of current is very large
Application
- RF mixer and detector diode
- Power divider in OR circuit
- As rectifier in the power supply of Solar Panels
- Voltage clamp to prevent transistor saturation
- High speed switching mechanism allows his TTL of digital devices such as computers and laptops