Are there N-MOSFET parameters which indicate a more robust gate, able to better withstand ESD, too high or too low voltage (at the gate) and be less prone to fail? The question is NOT about how to protect a N-MOSFET gate. Advice and suggestions are always welcome, of course, but the question is not about that. The question is about reading the data sheet to find parameters indicating a less fragile MOSFET gate.

First, I used MMBF170L, then I used the DMN6140L because it has a much lower rdson and higher current rating. Both suffered the same fate: Drain shorted with the source, sometimes slightly, sometimes a lot, but never totally.

The N-MOSFET gate is connected to a very long cable (~10m CAT5). Voltage applied to gate is 15Vdc. No frequency, no PWM: Only manual on-off. I suspect ESD, but switch bounce due to hardware switching is also suspected. I noticed that a 10K followed by a 15V zener somewhere between the switch and the gate resistor, followed by a 1K gate resistor just before the gate helped (for how long, I don't know). But a zener without the 10K before it was not enough to protect. I was surprised that the zener seemed to have no effect. There are also other protections upstream, at the switch, i.e for debouncing. We noticed very strong ESD, static electric sparks, during the installation. That's why I suspect ESD, but it can also be the effect of the long wire... or something I don't know. But again, the question is not about how to protect the gate, but which MOSFET parameters to look at. And is the the DMN6140L specifically weak in this regard?

^{simulate this circuit – Schematic created using CircuitLab}