junction breakdown

In electronics, a p-n junction is formed when a semiconductor crystal changes from p-type (acceptor impurities) to n-type (donor impurities). Near the junction, a depletion layer forms, acting as an insulator.

A key characteristic of p-n junctions is their ability to rectify, allowing current flow primarily in one direction. When a reverse bias is applied, a small leakage current flows until a critical breakdown voltage is reached. At this point, the current suddenly increases, a phenomenon known as junction breakdown. This can be a nondestructive process if power dissipation is controlled.1

A Zener diode is a type of p-n junction diode specifically designed with a precise impurity distribution to achieve a well-defined breakdown voltage. It is operated in reverse bias and used as a constant voltage source or for voltage protection.2