NOVEL STRUCTURES OF SILICON CARBIDE METAL SEMICONDUCTOR FIELD EFFECT TRANSISTORS FOR HIGH VOLTAGE AND HIGH POWER APPLICATIONS

摘要

A silicon carbide metal semiconductor field effect transistor (MESFET) that includes a double-channel layer, with the lower channel being higher doped than the upper channel and a recessed gate. The higher doped lower channel layer is used to increase the channel current while the lower doped upper channel layer is used to improve the gate-drain breakdown voltage. A part of the gate nearer to the source is buried so as to allow a wider channel opening outside the buried gate region, and consequently reduce the source and drain resistances. The unburied gate nearer to the drain functions as a field plate and decreases the electric field crowding at the corner of the buried gate nearer to the drain and hence improves the gate-drain breakdown voltage. Overall a higher operating voltage and higher output power density for the MESFET is attainable.