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Difference between Avalanche Breakdown and Zener Breakdown

Difference between Avalanche Breakdown and Zener Breakdown

Have you ever been confused while trying to differentiate between Avalanche Breakdown and Zener Breakdown? You’re not the only one! This phenomenon can be quite complicated and is often misunderstood. Luckily, this blog post will explain the subtle but important difference between these two breakdown mechanisms so that you are able to understand them better. Keep on reading to learn more about how Avalanche Breakdowns and Zener breakdowns occur in a semiconductor device, their similarities, and differences, as well as their applications in our everyday lives.

What is Avalanche Breakdown?

Avalanche breakdown is an interesting phenomenon that occurs when high electric fields collide with certain materials, leading to the emission of electrons and positively charged ions.

  • This process often results in a chain reaction due to the fact that the additional electrons created also become subjected to the same electric field, promoting further electron emission.
  • Avalanche breakdown is most often observed within materials under extreme electrical stress, such as gas-filled vacuum tubes and semiconductor devices like diodes. Avalanche breakdown can be classified into two types – Geiger-Muller (GM) or Townsend (T) Avalanche Breakdown.
  • GM Avalanche Breakdown has a lower signal speed than T Avalanche Breakdown, however, it requires less energy for its occurrence. Avalanche breakdown also has practical applications in particle physics as it helps scientists detect and study high-energy particles emitted by cosmic sources of radiation.

What is Zener Breakdown?

  • Zener Breakdown refers to a process in which a reverse voltage applied to a diode can cause current to flow. This process occurs under certain conditions when the Zener voltage of a semiconductor is exceeded, allowing electrons to briefly flow between two junctions.
  • Zener Breakdown offers many advantages over other breakdown models such as increased stability and reliability, potentially greater thermal performance, and cost savings.
  • The Zener Breakdown phenomenon has become one of the most heavily studied topics in electrical engineering due to its wide-reaching applicability and relevance in today’s ever-evolving technological landscape.

Difference between Avalanche Breakdown and Zener Breakdown

Avalanche breakdown and Zener breakdown are two different processes in which an electron loses energy and jumps from the conduction band to the valence band.

  • Avalanche breakdown occurs when the electric field intensity exceeds a certain threshold value, resulting in electrons being accelerated to high velocities and gaining enough energy to cause them to reach the conduction band after colliding with atoms during their free flight.
  • On the other hand, Zener breakdown occurs as electrons tunnel through a reduced energy barrier between two energy bands.
  • When they successfully do this, they acquire extra kinetic energy from an external electric field due to their collisions with atoms close to the junction.

The loss of kinetic energy experienced by these electrons affects both Avalanche Breakdown and Zener Breakdown, but Avalanche Breakdown occurs as a result of high-energy collisions rather than simply tunneling through a potential barrier.


Avalanche breakdown and Zener breakdown are two different types of electrical failures. An avalanche breakout is a situation where current flows through the gate-oxide layer in an uncontrolled manner, resulting in a large increase in current and power dissipation. A Zener breakdown is a situation where the voltage across a diode increases until it reaches its reverse break-over voltage, at which point electron emission begins. The difference between these two types of failure is important to understand when selecting components for your circuit.

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