Schottky diode is a low-power, high-current, ultra-high-speed semiconductor device developed in recent years. Its reverse recovery time is very short (can be as small as a few nanoseconds), the forward conduction voltage drop is only about 0.4V, and the rectified current can reach several thousand amperes. These excellent characteristics are unmatched by fast recovery diodes. Most of the small and medium power Schottky rectifier diodes are packaged.
The basic principle of a Schottky diode is to form a Schottky barrier on the contact surface of a metal (such as lead) and a semiconductor (N-type silicon wafer) to block reverse voltage. The rectification principle of Schottky and PN junction is fundamentally different. The withstand voltage is only about 40V. Its specialty is: the switching speed is very fast, and the reverse recovery time is very short. Therefore, switching diodes and low-voltage high-current rectifier diodes can be manufactured.
Schottky diodes are "metal semiconductor junction" diodes with Schottky characteristics. Its forward starting voltage is very low. In addition to tungsten materials, gold, molybdenum, nickel, titanium and other materials can also be used for the metal layer. Its semiconductor material is silicon or gallium arsenide, mainly nitrogen-type semiconductors. The device is conducted by majority carriers, so its reverse saturation current is much larger than a PN junction conducted by minority carriers.
Since the minority carrier storage effect in Schottky diodes is very small, its frequency response is only limited by the RC time constant. Therefore, Schottky diodes are ideal devices for high-frequency fast switching. Its operating frequency can reach 100 gigahertz. In addition, metal insulator semiconductor Schottky diodes can be used to manufacture solar cells or light-emitting diodes.
Schottky diodes use potential barriers formed by metal-semiconductor contacts to control current. Its main feature is reduced forward voltage (0.3V to 0.6V); in addition, it is multiphoton conduction and has a faster response speed than a few photonic devices. Schottky diodes are usually used as clamping diodes for the collector of the triode in the gate circuit to prevent the triode from being saturated and reducing the switching speed.
Schottky diodes are divided into two types of packaging: lead and surface mount (chip). Schottky diodes with leaded packages are usually used as high-frequency high-current rectifier diodes, freewheeling diodes or protection diodes. It has two packaging forms: single tube type and double tube (dual diode) type.