Monolithic Microwave Amplifier using a Two-Dimensional Electron Gas F.E.T. a Comparison with GaAs

We describe the fabrication of a single-stage monolithic circuit amplifier using a hete-rojunction two-dimensional electron gas FET. The same circuit configuration has also been realised on a classical GaAs FET wafer, permitting a direct comparison of the two materials. Both circuits show reasonable performance in X-Band, the GaAs amplifier giving a maximum gain of 7dB as compared to 5dB from the TEGFET, with good input and output matching. For the TEGFET, contact resistance does not seem to be a major problem, and the technology is compatible with conventional I.C. fabrication methods.