Schottky diode vs p-n diode-difference between schottky diode and p-n diode
This page compares Schottky diode vs p-n diode and mentions basic difference between Schottky diode and p-n diode. The symbol, structure, circuit and characteristics of both the p-n diode and Schottky diode are compared.
A p-n junction is the metallurgical boundary between the n-region and p-regions of semiconductor crystal. It consists of two semiconductor regions of opposite type. Such junctions will have profound rectifying behavior. They are known as p-n diodes. The figure-1 depicts normal p-n diode symbol.
The figure-2 depicts normal p-n junction diode structure. As shown p-n diode consists of p-n junction with one connection to p-side (e.g. anode) and another connection to n-side (e.g. cathode).
The figure-3 depicts normal p-n diode characteristic.
It shows characteristics for silicon and germanium diodes at temperature of 25 degree C.
They are used as rectifiers to change AC to DC in power supplies.
Silicon is preferred over germanium due to its following properties.
• It has much lower reverse current.
• It has higher breakdown voltage.
• It can work at high temperatures.
The figure-4 depicts schottky diode symbol.
In Schottky diode, a metal semiconductor junction at one end, and another metal semiconductor contact at the other end are formed. This is shown in the figure. Schottky diode uses metals such as tungsten Aluminium, chromium, platinum, gold etc. It uses N-type silicon as semiconductor material. The figure-5 depicts schottky diode structure and circuit.
The figure-6 depicts schottky diode characteristic. V-I curve of schottky diode is
steeper compare to normal p-n diode. As shown schottky diode has
lower forward voltage drop compare to p-n diode.
Refer Schottky diode basics>> for more information.
|Features||Schottky diode||P-N diode|
|Forward current||It occurs due to thermionic emission. (majority carrier transport)||It occurs due to diffusion currents. (minority carrier transport)|
|Reverse current||It is generated only due to majority carriers which overcome the barrier. (It depends less on temperature.)||It is generated due to minority carriers diffusing to the depletion layer and drifting to the other side. (It depends more on temperature.)|
|Cut-in voltage||It is small about 0.3V.||It is large about 0.7V.|
|Speed||It has high switching speed due to majority carrier transport. No recombination time needed.||It is limited by recombination time of injected minority carriers.|
|Ideality Factor||It is about 1 due to no recombination in depletion layer.||It is about 1.2 to 2.0 due to recombination in depletion layer.|
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