This afternoon I simulated a cascode, silicon nitride on the low side, under a SiC fet, EPC and Cree models. The Cree gate was held at +20V.
On turnoff, the SiC source flew up to +50, so I added a schottky diode
- resistor from gate to source to tame that.
It seems to work, but might be too tricky. I'll just use a screaming gate driver into the grounded SiC part.
Pity, because the GaN just needs a few volts of gate drive.
Somebody makes an integrated cascode, mosfet on the bottom, SiC above.