ZenerEffekt

ZenerEffekt, or Zener effect, is a breakdown mechanism in a reverse-biased p-n junction. It occurs when a strong electric field across a very narrow depletion region enables quantum mechanical tunneling of carriers from the valence band of the p-side to the conduction band of the n-side, producing a sharp and well-defined breakdown at a specific reverse voltage. This effect is most pronounced in diodes with heavy doping, which creates a thin depletion region and makes the tunneling process possible at relatively low voltages. The resulting breakdown voltage is largely temperature-insensitive compared with other breakdown mechanisms.

In practice, the Zener effect is one of the main mechanisms behind reverse breakdown in diodes and is often contrasted with avalanche breakdown. Avalanche breakdown arises from impact ionization in a wider depletion region and is more temperature-dependent. In heavily doped junctions, Zener breakdown can dominate at lower reverse voltages, while in lightly doped junctions, avalanche processes may prevail at higher voltages. Some diodes exhibit a combination of both, sometimes referred to as Zener–avalanche breakdown.

Historically, the effect is named after Clarence Zener, who analyzed diode breakdown in the 1930s. In modern electronics, devices designed to exploit this breakdown are called Zener diodes and are widely used for voltage regulation, reference voltage generation, and transient protection. The term ZenerEffekt is often encountered in German-language literature, and in many contexts it denotes the same fundamental tunneling-based breakdown mechanism.