Driving a MOSFET with fastest rise time possible
It's both the driver and the mosfet that determine the rise time. The net rise time is going to be about twice if both driver and mosfet are similar. You might also be interested in fall time and this can be harder to achieve especially if the gate isn't driven negatively when removing gate charge.

If the data sheets say 20 ns and there isn't some obvious improvement in the example circuit used to measure rise time then you are probably out of luck. Keep plugging away and look for better mosfets. I think there is a new type out referred to as something like silicon-carbide technology but don't quote me on it.