Schottky diodes are metal semiconductor devices made of precious metals (gold, silver, aluminum, platinum, etc.). ) As a positive electrode, an N-type semiconductor as a negative electrode, and utilizes the rectification characteristics of the barrier formed on the contact surface of the two. Because there are a large number of electrons in nitrogen-type semiconductors and only a very small amount of free electrons in precious metals, electrons diffuse from high concentration of boron to low concentration of boron. When a Schottky diode establishes a space charge region with a certain width, the drifting movement of electrons caused by the electric field and the diffusion movement of electrons caused by different concentrations reach a relative balance, thereby forming a Schottky barrier.
The internal circuit structure of the Schottky diode is based on a nitrogen-type semiconductor on which an arsenic-doped nitrogen epitaxial layer is formed. The anode is made of molybdenum or aluminum and other materials to form a barrier layer. Silica (silicon dioxide) is used to eliminate the electric field in the edge area and improve the pressure resistance of the tube. Schottky diodes have the advantages of high switching frequency and reduced forward voltage, but their reverse breakdown voltage is relatively low, mostly not higher than 60V, at most only about 100V, which limits its application range.
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 offers single tube and dual tube (dual diode) packages. Schottky diodes also have three pin-out modes: common cathode (the cathodes of the two tubes are connected), common anode (the anodes of the two tubes are connected), and series (the anode of one diode is connected to the cathode of the other diode). Surface mount Schottky diodes include single-tube, double-tube and triple-tube packages, with a-19 pin lead methods.