KISS said:
but it's really the same mechanism causing PRV
The correction was a minor technicality but an important one, the statement in quotes above is absolutely false. Avalanche and Zener breakdown are discretely separate breakdown modes and behave differently, specifically avalanche breakdown exhibits hysteresis where zener breakdown does not. Anything under 5 volts is going to be dominated by the zener breakdown and anything over is going to exhibit more avalanche breakdown (in general) Avalanche breakdown is more prevalent in lightly doped semi conductors and zener breakdown is more prevalent in heavily doped junctions, and as temperature increases zener breakdown diminishes and avalanche gains.
I'm not sure how true zeners are constructed on a fabrication level for voltages over about 5 volts but I suspect they're actually multiple zeners in series, or are in fact not truly zener diodes but hybrids which is why there's so much interchangeability of the terms avalanche and zener. It's something I'd like to delve into deeper but it's not easy to come across fabrication masks of cmos devices and details of the doping of specific components. I'd imagine you'd have to be deep in the industry to have any true knowledge of what is commonly out there.
I would hazard a guess that the only true zener diodes out there are the ones that are under 5 volts
KISS said:
All Avalanche diodes are called Zener diodes and both processes happen around 5.1 V
This again is absolutely false, for the reasons stated above. Both processes
can happen around 5.1 volts which one dominates is highly complicated and outside the scope of this discussion. It is simply important to note that the reasons for the breakdowns are different and move on, those that want to get into the physics a bit more can try to dig.
It's still non-destructive
This is mostly false, any zener or diode that exhibits breakdown over it's rated forward current will smoke, and possible sooner because the voltage will be higher at the same current so the dissipated power will be higher at the same current.
It's only non-destructive if something else limits the current, there is no inherent current limiting to either breakdown mode, being that your statement requires additional components to be in the circuit it is not appropriate to state about breakdown modes in general.