What is happening inside the zener diode ?

[Outrageous]

Refer to this graph
http://www.reuk.co.uk/What-is-a-Zener-Diode.htm

The zener diode
First the reverse biased set up then the depletion layer become bigger and bigger because the anode of the battery will attract the electron in n-type , leaving a lot of holes there. For the cathode, it will supply a lot of electrons to the p-type, increasing the depletion layer.
When the reverse voltage is continually supplied to the zener diode, a lot of energy will be given to the electrons in covalent bonds, then the electrons from covalent bond will break and jump from valence band to conduction band. This is what we called zener breakdown.( the electrons from the covalent bond is the minority charge carriers which resulting in more reverse current?)
And the electrons are continually being supplied with energy ,(the minority charge carriers or electrons become stronger and stronger?) then they will continually move in the circuit and then knock the atoms around them , again a lot of electrons will be produced either from the covalent bond or the valence electron of the atoms. This is what we called avalanche breakdown. (then how about the depletion layer there? Still there or is being destroyed?)
Then for one characteristic of zener diode ,the voltage is independent to the current. And from the graph we can see that when it is zener breakdown, there will be infinite current produced, because the graph show the current will go to infinity.(but how can the current go infinity since we have so limited atoms that make up the diode?) The zener diode as a voltage regulator can continue to supply constant voltage(is that mean the zener diode is able to keep voltage across it stable always?) and vary its own current to accommodate the circuit.(how the zener diode is able to vary the current just to suit the circuit? By controlling the minority charge carriers?)

This is so far what I know all about the zener diode , please correct me and answer me. Thank you very much.

 

[tiny-tim]

Duplicate thread!

Accidental duplicate to https://www.physicsforums.com/showthread.php?t=651052

 

[mistermotown]

I was told that Zener breakdown was due to tunneling... I'm no sure if that's correct though.

 

[Enthalpy]

Tunneling dominates under some 4V and corresponds to the field ionizing the atoms directly - in other words, taking valence electrons into the conduction band. These diodes are bad in that the I-V curve is too round for proper regulation, but they produce very little noise even at low frequency, less than a bandgap reference, so with much circuitry around they can be a good voltage reference for metrology.

At higher breakdown voltage, avalanche dominates, where impacts of fast electrons ionize atoms. These diodes have the square I-V curve that regulates efficiently. The current is limited by the rest of the circuit. Noise is stronger in these diodes but not so strong neither, is essentially white, and it depends on temperature (and light).

 

[alphysicist]

Inside a zener diode, there are two main processes occurring: zener breakdown and avalanche breakdown. When the diode is reverse biased, a depletion layer is formed between the p-type and n-type regions. As the reverse voltage increases, the depletion layer also increases in size. This is because the positive terminal of the battery attracts the electrons in the n-type region, leaving behind more positively charged holes. Similarly, the negative terminal supplies more electrons to the p-type region, increasing the depletion layer.

As the reverse voltage continues to increase, the electrons in the covalent bonds of the diode's atoms gain enough energy to break free and move into the conduction band. This is the zener breakdown. The electrons then move through the circuit, knocking other atoms and creating more electrons. This is the avalanche breakdown.

The zener diode is designed to have a specific breakdown voltage, known as the zener voltage. This allows it to maintain a constant voltage across its terminals, even with varying levels of current. As the reverse voltage increases, the zener diode will regulate the current to maintain a constant voltage. This is why the current in the graph appears to go to infinity - the diode is regulating the voltage, not the current.

The zener diode is able to vary its current to accommodate the circuit by controlling the number of minority charge carriers (electrons or holes) in the depletion layer. By adjusting the number of minority charge carriers, the diode can regulate the flow of current through the circuit to maintain a constant voltage.

I hope this helps to clarify the processes happening inside a zener diode. Please note that this is a simplified explanation and there may be other factors at play. Thank you for your interest and curiosity in understanding the zener diode.