High microwave performance ion-implanted GaAs MESFETs on InP substrates

Ion implantation was employed, for the first time, in fabricating GaAs MESFETs in undoped 2 mu m thick GaAs epitaxial layers directly grown on InP substrates by low-pressure MOVPE. The Si-ion implanted GaAs layer on InP substrates showed excellent electrical characteristics: a mobility of 4300 cm²/Vs with a carrier density of 2*10¹⁷ cm^-3 at room temperature. The MESFET (0.8 mu m gate length) exhibited a current-gain cutoff frequency of 25 GHz and a maximum frequency of oscillation of 53 GHz, the highest values yet reported for GaAs MESFETs on InP substrates. These results demonstrate the high potential of ion-implanted MESFETs as electronic devices for high-speed InP-based OEICs.