HIGH DRAIN CURRENT VOLTAGE PRODUCT OF SUBMICROMETER-GATE ION-IMPLANTED GAAS-MESFETS FOR MILLIMETER-WAVE OPERATION

Ion-implanted GaAs MESFET's with gate lengths of 0.3 and 0.5-mu-m have been fabricated using optical lithography. The devices with 0.3- and 0.5-mu-m gate lengths exhibit extrinsic transconductances, at zero gate bias, of 200 and 180 mS / mm at drain currents of 400 and 420 mA / mm, respectively. The gate-to-drain diode characteristics of these two different gate-length devices show similar breakdown voltages of 13-15 V. From S-parameter measurements, respective current-gain cutoff frequencies, f(t)'s, of 56 and 30 GHz are obtained for 0.3- and 0.5-mu-m gate-length devices. The high drain current-voltage product and the microwave performance indicate that ion-implanted technology has the potential to be used to manufacture power devices for millimeter-wave applications.