3-4) Schottky Diode

Question 1

What modes of operation can a Schottky Diode operate in?

Answer 1

Both forward and reverse bias.

Question 2

What makes a Schottky diode distinct from a regular P-N junction diode?

Answer 2

Instead of having an implanted P-layer, action occurs at the interface between the barrier metal and the silicon. Guard rings are used to make the device’s reverse breakdown characteristics more rugged. Since both metal and silicon and N-type materials, conduction occurs through majority carriers only, with no minority carrier injection, storage or recombination.

Question 3

What does a Schottky diode lack compared to a typical PN Junction Diode?

Answer 3

There is no P-type semiconductor material and therefore no minority carriers (holes), when reverse biased, the diodes conduction stops very quickly and changes to blocking current flow, as for a conventional PN-junction diode. Thus for a Schottky diode there is a very rapid response to changes in bias and demonstrating the characteristics of a rectifying diode.

The knee voltage at which a Schottky diode turns “ON” and starts conducting is at a much lower voltage level than its PN-junction equivalent.

Question 4

What is the typical forward bias voltage drop for a Schottky diode?

Answer 4

0.25V to 0.4V and low junction capacitance