ABSTRACT
To show the effects of buffer structures on GaAs MESFET's, we investigated eight different buffer layers grown on semi-insulating GaAs substrate by Molecular Beam Epitaxy(MBE) and chose four among them to characterize the MESFET performances. We found that AlGaAs/GaAs superlattice layer in the buffer helped the devices to have better performances such as large source-to-drain resistance, small knee voltage and larger gain flatness. Also it was demonstrated that the thickness of intrinsic GaAs spacer layer between AlGaAs/GaAs superlattice and active channel layer must be carefully selected (between 500 Å ~ 1000 Å) to have low knee voltage and better gain flatness.
