What is Zener Breakdown and Avalanche Breakdown and Their Differences

The breakdown diode can be defined as; it is a two terminal electrical component, and the terminals are anode as well as the cathode. There are different types of diodes are available in the market which are fabricated with semiconductor objects namely Si (Silicon) & Ge(Germanium). The basic function of the diode is, it allows the current flow in only one direction and blocks in the reverse direction.

An electrical breakdown can occur for any materials like conductor, metal, insulator; semiconductor due to two types of occurrences like Zener as well as an avalanche. The main difference between these two is the occurrence of their mechanism due to the high electric field and the collision of flowing electrons by atoms. Both the breakdowns can happen concurrently. This article gives an overview of the difference between Zener breakdown as well as avalanche breakdown.

What is Zener breakdown and Avalanche Breakdown?

The Zener Breakdown and Avalanche Breakdown concept mainly include an overview of Zener Diode, Zener Breakdown, Avalanche Diode, Avalanche Breakdown, and its main differences.

What is a Zener Diode?

The Zener diode can be defined as; it is a special kind of diode when we compare with other diodes. The flow of current in this diode will be in a forward direction or in reverse direction. The Zener diode includes an individual and heavily doped PN-junction, which is intended to perform in the reverse bias direction when a particular voltage is reached. This diode contains a reverse breakdown voltage for current conducting as well as continuous operation in the mode of reverse bias without getting smashed. In addition, the voltage drop at the diode will remain stable over an extensive voltages range, and one of the main characteristics will make this diode suitable for utilizing in voltage regulation. Please refer the link to know more about Zener Diode Working Principle and Applications.

Zener Diode
Zener Diode

What is Zener Breakdown?

The Zener breakdown mainly occurs because of a high electric field. When the high electric-field is applied across the PN junction diode, then the electrons start flowing across the PN-junction. Consequently, expands the little current in the reverse bias.

When the electron moving enhances beyond the diode rated capacity, then the avalanche breakdown will occur to break the junction. Therefore, the flow of current in the diode is incomplete the diode will not damage the PN-junction. However, avalanche breakdown will damage the junction.


What is Avalanche Diode?

An avalanche diode is intended to experience the breakdown at a particular reverse bias voltage. This diode junction is mainly designed for avoiding the concentration of current so the diode will not damage with the breakdown. Avalanche diodes are utilized as support valves to control the pressure of the system to save from overvoltages. The symbol of this diode, as well as Zener diode, is similar. Please refer the link to know more about Construction and Working of Avalanche Diode

Avalanche Diode
Avalanche Diode

What is Avalanche Breakdown?

The avalanche breakdown happens due to the saturation current in reverse bias. So when we amplify the reverse voltage, then the electric field will automatically increase. If the reverse voltage and the width of the depletion layer are Va & d, then the electric field which is generated can be measured using the formula Ea = Va/d.

These mechanisms will occur in PN junctions which are doped lightly where the depletion area is somewhat extensive. The density of doping regulates the breakdown voltage. The avalanche method temperature coefficient increases, then the temperature coefficient of the magnitude will be increases by rising breakdown voltage.

Difference between Zener and Avalanche Breakdown

The difference between Zener and avalanche breakdown include the following.

  • The Zener breakdown can be defined as the flow of electrons across the p kind material barrier of the valence band to the evenly filled n-type material conduction band.
  • The avalanche breakdown is an occurrence of raising the flow of electric current or electrons in insulating material or semiconductor by giving the high voltage.
  • The depletion region of the Zener is thin whereas the avalanche is thick.
  • The connection of the Zener is not-destroy whereas the avalanche is destroyed.
  • The electric field of the Zener is strong whereas the avalanche is weak.
  • The Zener breakdown generates electrons whereas the avalanche generates holes as well as electrons.
Zener BreakDown and Avalanche BreakDown
Zener BreakDown and Avalanche BreakDown
  • The doping of the Zener is heavy whereas the avalanche is low.
  • The reverse potential of the Zener is low whereas the avalanche is high.
  • The temperature coefficient of the Zener is negative whereas the avalanche is positive.
  • The Ionization of the Zener is due to Electric field whereas the avalanche is the collision.
  • The temperature coefficient of the Zener is negative whereas the avalanche is positive.
  • The breakdown voltage (Vz) of the Zener is inversely proportional to temperature (ranges from 5v to 8v) whereas the avalanche is directly proportional to temperature (Vz > 8V).
  • After the breakdown of the Zener is voltage remains constant whereas the avalanche is voltage vary.
  • The Zener breakdown V-I characteristics have a sharp curve whereas the avalanche doesn’t have a sharp curve.
  • The breakdown voltage of the Zener decreases when the temperature increases whereas the avalanche increases when the temperature increases.

Thus, this is all about Zener breakdown and Avalanche Breakdown. From the above information finally, we can conclude that generally there are two different breakdowns are distinguished based on the concentration of doping bias in the PN-junction. Whenever the PN-junction is doped highly then the Zener breakdown will happen whereas the avalanche breakdown will occur due to lightly doped PN-junction. Here is a question for you, what are the VI-characteristics of Zener breakdown and Avalanche Breakdown?