Abstract

It is shown that an intermediate Si epitaxial layer in the GaAs on Silicon system is critical for attaining state of the art MESFET microwave performance. Devices with gate length of 1.3um and width 180um showed unit current gain cutoff frequency (ft) up to 18GHz and maximum power gain cutoff frequency (fmax) of about 30GHz. These results indicate that MMICs can be developed on GaAs/Si/Si wafers with a processing technology suitable for GaAs-Si monolithic integration. The critical requirements for MMICs on Si are also presented.