0.25-µm Gate Millimeter-Wave Ion-Implanted GaAs MESFET’s

Querter-micrometer gate ion-implanted GaAs MESFET’s which demonstrate device performance comparable to AlGaAs/InGaAs pseudomorphic HEMT’s have been successfully fabricated on 3-in-diameter GaAs substrates. The MESFET’s show a peak extrinsic transconductance of 480 mS/mm with a high channel current of 720 mA/ mm. From 5-parameter measurements, the MESFET’s show a peak current-gain cutoff frequency ftof 68 GHz with an average ft of 62 GHz across the wafer. The 0.25-µm gate MESFET’s also exhibit a maximum-available-gain cutoff frequency fmax greater than 100 GHz. These results are the first demonstration of potential volume production of highperformance ion-implanted MESFET’s for millimeter-wave application.