Schottky diodes are an electrical component that allow voltage to flow one direction, with a very low forward voltage drop. Schottky diodes are sometimes known as Schottky rectifiers, and have been in use for more than 25 years. The diodes are usually used in radio frequency settings and as power rectifiers. In part, Schottky diodes are popular because of their successful use in very-high-frequency settings, though they offer various levels of capacitance.
Schottky diodes come in a variety of forms, with some more effective than others. One such form is the point contact diode, where a metal wire is positioned against a semiconductor surface. This form of the Schottky diode is somewhat unreliable, however, as the wire needs constant positioning to function effectively. The point contact Schottky diode was soon replaced by the more reliable vacuum deposited Schottky diode, where a piece of metal was vacuum deposited between the metal wire and the semiconductor surface. This design gradually wears on the edges of the deposited metal, and so was replaced by the most current form, where the semiconductor is separated from the Schottky barrier metal by a guard ring.
Low Forward Voltage Drop
One of the main advantages to Schottky diodes is the diode's low voltage drop compared to other components. As electricity flows across the diode terminals, a normal diode drops between 0.7 and 1.7 volts. Schottky diodes, on the other hand, drop approximately 0.15 to 0.45 volts, which results in much higher system efficiency.
Fast Recovery Time
The other main advantage of the Schottky diode is its fast recovery time--these diodes are extremely fast and exhibit little reverse recovery time. This is behind the Schottky diodes common use in switching regulator circuits and its popularity in high-frequency devices. The Schottky diode's fast recovery time can even eliminate the need for snubber circuits, which are commonly required with other types of fast rectifiers.
SiC Schottky Diodes
Silicone carbide (SiC) Schottky diodes are the newest innovation in Schottky diodes and boast a variety of improvements. This new type of diode has an even lower forward voltage loss than traditional Schottky diodes, and are easily paralleled for higher currents. SiC schottky diodes are also able to function at optimum performance levels regardless of temperature--something tradition Schottky diodes cannot do.