Comment by namibj

Well, SiC MOSFET do get used, but yeah. SiC JFETs are indeed better, lower lower with the same wafer technology, avalanche proof, high heat proof (the polyimide passivation hurts beyond ~220 C).

Much easier to drive when you stack them for HV.

That said, GaN is there for capacitive converters due to being able to run very efficient at >10 MHz switching frequency.

These converters in principle fit in very compact phase change coolant/insulator vessels, for example with propane. The capacitors at those frequencies get to be tiny, like, smaller than the transistor package by volume.