DIRECT-SCHOTTKY-CONTACT INP MESFET

We report the design and fabrication of an InP MESFET with excellent I-V characteristics. We measured a record high transconductance of 110 mS/mm for a 1-mu-m gate length direct-Schottky-contact InP MESFET, where the InP surface was not passivated or treated prior to the deposition of the gate contact. Microwave measurements show an f(max) of 11.6 GHz for this typical nominal 1-mu-m gate length device. A p-type planar doped layer was inserted between the buried n-type channel and the device surface at 18 nm from the gate metal. This planar layer enhances the Schottky barrier height and device performance.