SiC surface engineering for high voltage JFET applications

Buried-gate junction field-effect transistors with operation voltages up to 600-700 V have been fabricated in 6H polytype silicon carbide using a mesa-isolation technology. The devices maintain drain currents up to 40-60 mA and have the pinch-off voltages of 30-40 V. The treatment of the channel surface in a hydrogen plasma is shown to be an effective method to improve the current-voltage characteristics of such transistors. The effect of plasma treatment is explained by stabilization of surface charge which can act in JFET as an additional "floating" gate.