Schottky Barrier Diodes

Schottky diodes, in their simplest form, consist of a metal layer that contacts a semiconducting element. This metal / semiconductor junction exhibits rectifying behavior (i.e., the current passes through the structure more readily with one polarity than the other). Schottky diodes are used primarily in high frequency and fast-switching applications. Because they operate only with majority carriers, there is no reverse leakage current as with other types of diodes.

With Schottky diodes, the metal region is heavily occupied with conduction-band electrons. The N-type semiconductor region is lightly doped. When forward-biased, the higher energy electrons in the N-region are injected into the metal region, where they give up their excess energy very rapidly. Since there are no minority carriers (as with conventional rectifier diodes), there is a very rapid response to a change in bias. For this reason, Schottky diodes are used in high-frequency applications and in many digital circuits to decrease switching times. Schottky diodes are also known as hot-carrier diodes.