Schottky diode, operation and applications!


Semiconductors are components that are part of our daily lives, being essential for the functioning of electrical devices and equipment. Knowing the importance of these semiconductors, the World of Electrical decided to talk about the diodes, especially about the Schottky diode. We discuss in this article what is a Schottky diode, what are the applications of the Schottky diode and what are its characteristics. Come on, guys!

What is a diode?

The diode is an electronic component that, according to its polarization, allows the passage of electric current in only one direction. We can make a simple analogy by comparing the diodes with valves that only let water flow in a single direction, that is, the diode does the same thing with the electric current.

We need to be aware that none of the electronics is ideal, that is, no component is perfect. Therefore, to make a common diode conduct electricity you need to supply it with a voltage of at least 0.7V between anode and cathode if we consider silicon diodes. In addition to conventional diodes, we can mention other types of diodes such as Schottky diode, photodiode, Gunn diode, Zener diode, and tunnel diode. Each of them has different characteristics to meet the most varied applications.

Schottky Diode: What is it?

The Schottky diode is a semiconductor component and is named after the German physicist Walter Hermann Schottky. The Schottky diode is characterized by ultra fast switching, and when it is directly polarized it has a very low voltage drop.

Unlike the common diode, the Schottky diode is not formed by a PN junction, because the Player is replaced by a metal layer, forming a Metal-N junction. The material and technology used in the manufacturing process of the Schottky diode and the common diode is what differentiates the conduction characteristics of the Schottky diode in relation to the other diodes.

These characteristics of the Schottky diode make this type of diode special in many applications, developed to meet the needs of switching and protection circuits such as switched circuits and transient protection circuits.

Schottky Diode: Advantages and Disadvantages

Schottky diodes are relatively new components. Their special characteristics make them ideal for certain applications, especially when common diodes are not capable of acting in such situations. The Schottky diode does have many advantages, but it also has some disadvantages in relation to its use and must be taken into account.

The main advantage that we can mention is its switching speed which is very fast, in addition to its voltage drop in the direct direction, which is extremely low compared to the voltage drop of other diodes, such as the rectifier diode for example.

We can highlight that the main disadvantages of the Schottky diode are not to withstand high temperatures, to have a high leakage current in the reverse direction and its reverse rupture voltage is generally less than 100V, which limits its use in higher power circuits. Below is an image with the characteristic curve of the Schottky diode compared to the common diode, in addition to its respective characteristics.

What is a Shottky diode and what are its characteristics?

Symbology of the Schottky Diode and its characteristic curve, compared to that of the common silicon diode.

Schottky Diode: Applications

In designs with audio amplifiers, silicon transistors and diodes start to conduct with a relatively high voltage (0.7V), which can cause distortions in the signals. There are modern components with technologies that are able to minimize this problem to a certain level of distortion that is far below the levels that our ears can detect. However, it is important to highlight that it is not only in amplifier circuits that the presence of silicon in semiconductors can affect a circuit, as they can generate noise.

The Schottky diode for having an extremely fast switching time, on the order of nanoseconds and even less. They can perfectly replace common silicon diodes in amplifier sources, preamps, CD players, digital processors, among others.

If you want to learn more about semiconductor devices, the video below the Mundo da Elétrica channel shows in practice how a rectifier diode works and surveys the characteristic curve of the diode.