Microwave MESFET's fabricated in GaAs layers grown on SOS Substrates

Device-quality GaAs layers have been grown on silicon-on-sapphire (SOS) substrates by molecular beam epitaxy (MBE). Microwave MESFET's (gate length of ~0.8 µm) with transconductance of 140 mS/ mm,f_{max} = 20GHz, andf_{T} = 8.3GHz have been fabricated in these layers.