Well, the wording is definitely marketing. But no, they don't mean so fast you won't care, they mean they actually don't have a reverse recovery time. And yes, these diodes are fundamentally different, but they exist and you've probably even used one.
They're called Schottky diodes. Though it's sort of marketing spin to say they have zero recovery time. This implies they are able to do something instantaneously. But it isn't that they have zero recovery time, it's that Schottky diodes don't have reverse recovery charge or recovery time at all. Those terms are not applicable to them and have no meaning in regard to schottky diodes. Schottky junctions do not switch on or off, and something that isn't a switch obviously can't have a switching time. Charge doesn't impact the behavior of the junction, and there is nothing to recover from in the first place, so 'zero recovery diode' is just fancy marketing speak for Schottky diodes.
Schottky diodes are fundamentally different, and are constructed of a metal-semiconductor junction, as opposed to a semiconductor-semiconductor junction like PN junction ('silicon') diodes. PN junctions actually turn on and become conductive in both directions, and take time to turn off, which is, of course, the reverse recovery time.
Metal-semiconductor junctions do not switch on or off, they don't do anything. Their behavior is simply a property of the junction itself. Due to the chemical interface of the metal and semiconductor, the center of the semiconductor's band gap (the gap separating the valance band and conduction band) is 'pinned' to the fermi energy of the metal (since electrons will occupy all possible energy states in a conductor, the surface of this 'electron sea' above which no higher energy states exist to be filled is called the fermi energy).
It's helpful to visualize the metal as a bucket of water and the fermi energy is simply how tall the bucket is. The semiconductor as two pipes, one above the other, with a fixed height in between them. The lower pipe we can ignore, it's the valance pipe and is below the height of the bucket. When we bring the pipes up to the bucket, the center of that gap between the top and bottom pipe is 'pinned' to the height of the bucket. This is called fermi pinning. Why fermi penning occurs is some Seriously Hard Physics that I'll leave up to the reader to discover on their own, if they wish to.
Since the center of the gap is at the same level as the bucket, the top pipe is a bit above the height of the bucket. Now, if you pump water into the top pipe, it can freely pour out of the end into the bucket, like a waterfall. But you'll never get the water in the bucket to go into the pipe above it, because the water will just over flow over the sides of the bucket, it will never gain enough height to reach the pipe.
This is a very gross simplification and takes a lot of artistic license, but that's the gist of a Schottky diode. The energy needed for electrons to pass from metal to semiconductor is not reachable, though a few electrons fly off via thermionic emission (which we see as reverse leakage current. And yes, I mean thermionic emission like in vacuum tubes). The energy needed for electrons to move from semiconductor to metal is easily obtained, and so we see an exponential VI curve. But Schottky diodes actually don't conduct at all in one direction (except by indirect thermionic emission due to vacuum gaps in the mismatched crystal lattices where the metal and semiconductor interface, but this is due to the vacuum, not true ohmic/galvanic conduction), but conduct readily in the opposite direction.
If you can find a meaning for 'recovery' and 'recovery charge' in any of that, let me know. I sure can't. Small signal Schottky's do not have recovery current, nor do they have reverse recovery charge, but many datasheets will incorrectly refer to capacitive charge stored that will discharge back out (like any other charge stored in parasitics) as 'reverse recovery charge'. But this is unavoidable and not caused by the junction itself, but a side effect and fact of life. No current ever conducts across the junction, and the stored charge doesn't need to be removed to prevent reverse currents from flowing. The charge is just something there, but it does not play any role in the function of the diode.
So when a small signal Schottky says it has a 100ps recovery time, that's actually not true. There is some parasitic capacitance that has an RC time constant much shorter than 100ps (or maybe is simply 100ps) but this is a parasitic effect that would exist regardless. It is not caused by the diode itself. In fact, the diode package of small signal diodes is the main contributor to this incorrectly named 'recovery time'.
Now, larger Schottky diodes have more significant capacitance, but again, it is fundamentally different and not recovery. It is an unavoidable parasitic capacitance discharging out, but no reverse current ever actually conducts across the Schottky barrier. Just equal but opposite amounts of charge on either side is leaving both sides at once, but it was already there. Just like any other capacitor.
HOWEVER, the largest Schottky diodes with higher reverse voltages (>50V is the rule of thumb I've heard but I don't really know for sure) require a guard ring to shape the electric field gradient so as to not cause dielectric breakdown in the barrier. This adds significant capacitance, and worse, creates a parasitic PN junction diode that WILL have reverse recovery time and charge. But this is accidental.
Silicon Carbide Schottky diodes have fantastic breakdown properties, and so they are true Schottky junctions and obtain the high voltages you see without the use of any guard ring or other parasitic structures, so yes, they really are 'zero' recovery time diodes. There is no recovery charge, and no recovery time, and no parasitic PN junction diode that can get turned on. But that's just what every small signal Schottky diode has always been. It IS very impressive and an amazing technological development, but from using silicon carbide. SiC FETs and Schottky devices are just bonkers. In performance and price. Hopefully the price part will change though with time, then they'll just be awesome.
Best Answer
Schottky diodes do not have reverse recovery time. Recovery from what? In a normal p-n junction diode, there is a charge carrier depletion region, and so the correct polarity electric field applied (the voltage drop) is actually switching it from non-conducting to conducting. If that field is removed, or applied in the opposite polarity, it is switched off again, but p-n junction diodes are very much switches that must turn on and off, and take time to do so, and that is the recovery time.
Schottky diodes are not constructed using two semiconductor junctions like p-n diodes. They are a metal-semiconductor junction. Due to some pretty nontrivial quantum physics which is beyond the scope of this question, Schottky diode junctions actually behave like true one-way valves. Something called the work function, which is the energy needed to 'dislodge' an electron out of a material and into the vacuum directly adjacent to the material, is very high for metals, but very low for semiconductors, at least when they form a junction with each other. Again, this is a huge oversimplification, and there are a lot of other things going on, but the gist is that the interface of the metal and semiconductor create a very tiny 'vacuum' depletion zone, one that is easily crossed via thermionic emission (yes, like how a vacuum tube works) from the semiconductor to the metal, because the work function is very low in the semiconductor. But in the metal, the work function is very high indeed, and it just takes too much energy to dislodge electrons out of the metal and into the semiconductor. A few electrons do make it, but because they are statistical outliers that managed to get the huge amount of thermal excitation needed to leave the metal. Otherwise, electrons pass easily from semiconductor to metal, but pass essentially not at all from the metal to semiconductor.
So, Schottky diodes do not have reverse recovery time because they do not have anything to recover from. However, the vacuum is effectively acting as a dielectric in one direction, so there is some small amount of parasitic capacitance. The reverse current seen in Schottky diodes is not actually reverse conduction, but merely a capacitive discharge. This is why Schottky's are said to have 'soft' recovery, as the curve is really just a capacitor discharge curve, and that takes time. But it is not 'on' and allowing reverse current flow. All the current flowing in reverse is due to energy stored capacitively from the diode itself.
One final caveat: In the larger, high power Schottky diodes, due to their physical construction (to shape the electric field so as to not cause dielectric breakdown across the vacuum barrier) have a guard ring that forms an entirely separate parasitic p-n junction in the Schottky diode. With low forward bias, it remains largely invisible, and the capacitance is all that matters. This is why datasheets always have the reverse recovery time listed for a very small forward voltage. Unfortunately, as the forward bias increases, it will eventually turn on the parasitic p-n diode junction through which reverse current can flow until switched off, thus vastly increasing the effective recovery time. The Schottky junction itself is still without a recovery time, as it has nothing to recover from, but the separate parasitic p-n junction does need to recover.
So be warned, the reverse recovery times for high power Schottky diodes are generally measured with forward bias too low to turn on this parasitic junction, but in real world applications, the recovery time mentioned is, and this is being generous, "very optimistic." It's frustrating (and intentional) that the recovery times under higher biases are often left out entirely of datasheets.