Compound semiconductors for low-noise microwave MESFET applications

In order to determine the low-noise potential of microwave MESFET's fabricated from materials other than GaAs, a one-dimensional FET model is employed. From material parameters and device geometry the model enables the calculation of a small-signal equivalent circuit from which performance information is acquired. Material parameters, as predicted from Monte Carlo calculations, are used to simulate 1-µm devices fabricated from GaAs as well as InP, Ga0.47In0.53As, InP0.8As0.2, Ga0.27In0.73P0.4As0.6, and Ga0.5In0.5As0.96Sb0.04. Results obtained from simulations comparing a Ga0.5In0.5As0.96- Sb0.04device to an equivalent GaAs device indicate that a decrease in minimum noise figure of almost a factor of two is possible. Considerable improvement in noise performance over a GaAs device is also predicted for devices fabricated from Ga0.47In0.53As and Ga0.27In0.73P0.4As0.6. In addition, the quaternary and ternary devices as well as the InP device should exhibit superior gain and high-frequency performance compared to GaAs devices.