Advantages of Schottky barrier diode | disadvantages of Schottky barrier diode
This page covers advantages and disadvantages of Schottky barrier diode. It mentions Schottky barrier diode advantages or benefits and Schottky barrier diode disadvantages or drawbacks. It also describes Schottky diode basics.
What is Schottky barrier diode?
• They are made with N-type silicon on which thin layer of metal is deposited. Here semiconductor forms cathode and metal forms anode. Typically anode materials include nickel chromium and aluminium, although other metals such as gold are also used.
• They have ON-voltage of about 0.3V where as it is 0.7V for P-N junction diode.
• The figure-1 depicts schottky diode and its equivalent circuit. As shown it is made of thin silicon substrate by growing epitaxially on n-type active layer having 2 micron thick. A thin SiO2 layer is grown thermally over active layer. Metal semiconductor junction is formed by depositing metal over SiO2.
• When device is forward biased, major carriers can be easily injected from highly
doped n-semiconductor material into metal.
• When device is reverse biased, barrier height becomes too high for electrons to cross and no conduction takes place.
Refer Schottky barrier diode basics >>.
Benefits or advantages of Schottky barrier diode
Following are the benefits or advantages of Schottky barrier diode:
➨These diodes are used in wide applications where other diodes are not suitable. Some of these applications are RF mixers, Detector diode, solar cell, voltage clamping devices etc.
➨It offers low turn on voltage which is about 0.2 to 0.3 Volts.
➨These diodes do not have recovery time when switching from conducting to non-conducting state and vice versa compare to P-N junction diodes.
➨It offers fast recovery time. This means small amount of stored charge can be used for high speed switching applications.
➨It offers low junction capacitance. It occupies very small area after the result obtained from wire point contact of silicon.
➨It can operate at high frequencies compare to PN junction diode. They are used as fast switches at microwave frequencies.
➨I0 of schottky diode is much larger compare to PN junction diode which depends on fB.
Drawbacks or disadvantages of Schottky barrier diode
Following are the disadvantages of Schottky barrier diode:
➨They operate at low voltages (about 50V) compare to P-N junction diodes. These diodes can not withstand much higher reverse voltage without break down. As a result it conducts large amount of current.
➨The schottky diode has relatively higher reverse current.