Correlation between high-speed device performance and defects in multilayer structures recognized by nondestructive microwave methods.

A nondestructive microwave (MW) technique proposed recently in [1] for characterization of multilayer (ML) structures on semi-insulating substrates is applied to examine epitaxial and ion-implanted GaAs n⁺-n-i structures intended for high-speed device fabrication. The influence of the interface properties of the ML structures on the device performance has been studied. The low-noise MESFETs fabricated on structures with imperfect interfacial regions were shown to exhibit an increased noise factor and decreased associated gain. A close relation between the amplitudes of the backgating effect in MW characterization tests and the sidegating effect in monolithic ICs is shown.