Why does Zener breakdown differ from avalanche breakdown in doped semiconductors?

[Stonestreecty]

TL;DR

The avalanche breakdown occurs because of the ionisation of electrons and hole pairs whereas the Zener breakdown occurs because of heavy doping. The Zener and the avalanche effect may occur simultaneously or independently of one another in PN junction. What the key points of them?

Good day, all
I am familiar with both of terms that I speak of in title. But I cannot find a full answer, so I might as well ask the PhD'ers here. What is really happening in Zener and Avalanche breakdown? I have read Guide to Zener Effect and Avalanche Effect and still feel confused.
And yes I get that impact ionization thing etc. But still, how does Zener differ from Avalanche breakdown? Why is doping so important? How come it doesn't damage the diode? Why is current constant? Why would it be constant when u exceeded the depletion zone(reverse bias), current should be proportional to voltage? (more voltage, more energy, more charges pulled out, more current) I am trying to get a full picture here. You may post something with detailed quantum mechanics, semiconductor theory.

Thank you in advance.

 

[LvW]

1.) Z (Zener) diode:
When the field strength exceeds the critical value of about 1E5 V/cm, the field forces are so strong that the electrons are torn out of the lattice. This causes the current to rise explosively.

2.) Avalanche diode:
At very high velocities of the minorities, there is a secondary effect where more charged carriers are torn out of the lattice - and the current rises explosively (like an avalanche)

3.) It is important that the temperature dependencies of both effects have different signs: The tempco is negative for Zener effects (Vz<5.6 volts) and positive for avalanche effects (Vz>5.6 volts).
At a Z-voltage of about Vz=5.6 volts, both temperature effects almost compensate each other.