High drain current-voltage product of submicrometer-gate ion-implanted GaAs MESFET's for millimeter-wave operation

Ion-implanted GaAs MESFETs 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, current-gain cutoff frequencies, f/sub t/s, of 56 and 30 GHz are obtained for 0.3- and 0.5- mu m gate-length devices, respectively. 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.<
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