schottky diode
The Schottky diode is a diode which differs in structure from the two- layer semiconductor diode in that the anode is not formed by a p-doped semiconductor but by a low-capacitance metal electrode. Thus, it has no pn junction between two semiconductors between cathode and anode, but a metal-semiconductor junction.
The space charge region at the semiconductor-metal junction, which is the pn junction between the n-doped silicon and the metal electrode, is depleted of charge carriers and has an extremely low capacitance, which is reflected in the extremely high switching speed. Schottky diodes are characterized by a low voltage drop of about 400 mV in the forward direction. In contrast, silicon diodes are at 700 mV. Schottky diodes have the shortest reverse delay times and, as a result, extremely short switching times of 1 ns to 3 ns. Both parameters, the voltage drop and the reverse delay time, are decisive for the high efficiency of Schottky diodes.
Accordingly, the area of application is in overvoltage protection and especially in fast electronic switches and logics, for which special Schottky TTLs are available. Schottky TTLs( S-TTL) are available with reduced power consumption, such as the low-power Schottky TTL( LS-TTL) and the advanced low-power Schott ky TTL( ALS-TTL), and with extremely short switching times, such as the advanced Schott ky TTL( AS-TTL).
The characteristic curve of Schottky diodes is much steeper than that of germanium diodes. The forward voltage is 0.4 V, the reverse voltage is about -50 V. Schottky diodes can be used up to a maximum voltage of 200 V. Because of their low forward voltage and short switching times, Schottky diodes have a much lower power dissipation than silicon diodes.
The Schottky effect is named after the German physicist Walter Schottky (1886-1976).