ON Semiconductor's SiC cascode JFET uses a vertical SiC JFET that has a much lower RdsA than lateral GaN FETs, even at 650 V.
It can also be scaled to much higher voltage ratings, and the cascode devices use special custom LV MOSFETs to simplify FET operation and provide gate drive compatibility with all existing SiC MOS and Si IGBT/MOS switches.

The main structural reason why ON Semiconductor's SiC cascode JFET is superior comes from the Cds=0 JFET structure, which means that the voltage divider problem during fast switching that occurs with GaN cascodes does not occur with SiC cascodes.